The Active Network

Frequently Asked Questions
DVD Frequently Asked Questions

This is the 6-May-98 revision of the FAQ for the Usenet newsgroup. (See below for what's new.)
Please send corrections, additions, and new questions to Jim Taylor <>.

Note: New DVD newsgroups have been created in the hierarchy. The FAQ will be posted to these newsgroups when the header change has been approved.

Where can I get this FAQ?

Recent significant changes (last posted to newsgroups on Mar 18):

  • 98-05-06: There's now a French translation of this FAQ. (Thanks, Zahir!)
  • 98-02-25: New intro to production (5), and corrections and updates to authoring info (5.2).
  • 98-02-21: Competing DVD audio formats. (1.12)
  • 98-02-21: Updates to player info. (1.5)
  • 98-02-20: Lots more RSDL discs. Please supply switch times if you have them. (1.27)
  • 98-02-20: Fox is supporting Divx. (2.10)
  • 98-02-20: Info about new digital copy protection proposal. (1.11)
  • 98-02-20: Basic details of DVD-Audio draft. (3.6)
  • 98-02-20: Additions to DVD-ROM list, links to most companies' Web sites. (6.2)
  • 98-02-12: Many updates to player info. (1.5)
  • 98-02-09: There's now a Spanish translation of this FAQ. (Thanks, Modesto!!)
  • 98-02-05: More DVD authoring systems. (5.2)
  • 98-01-22: Link to Eric's drive info page. (1.5)
  • 98-01-20: MultiRead and Type II updates for CD-R compatibility. (2.43)
  • 98-01-18: New question: [1.28] The disc says Dolby Digital. Why do I get 2-channel surround audio?
  • 98-01-18: Pointer to rental locations database. (1.15)
  • 98-01-18: Pointer to Chris' title list. (1.6)
  • 98-01-18: Reality check and a few new predictions. (1.9)
  • 98-01-13: Links to DVD primers from Nimbus and Sonic. (6.3)
  • 98-01-13: Explained THX (Thanks, Wayne). Added a few more audio format details. (3.6)


[1] General DVD

[1.1] What is DVD?

DVD, which stands for Digital Video Disc, Digital Versatile Disc, or nothing, depending on whom you ask, is the next generation of optical disc storage technology. It's essentially a bigger, faster CD that can hold video as well as audio and computer data. DVD aims to encompass home entertainment, computers, and business information with a single digital format, eventually replacing audio CD, videotape, laserdisc, CD-ROM, and perhaps even video game cartridges. DVD has widespread support from all major electronics companies, all major computer hardware companies, and about half of the major movie and music studios, which is unprecedented and says much for its chances of success (or, pessimistically, the likelihood of it being forced down our throats).

It's important to understand the difference between DVD-Video and DVD-ROM. DVD-Video (often simply called DVD) holds video programs and is played in a DVD player hooked up to a TV. DVD-ROM holds computer data and is read by a DVD-ROM drive hooked up to a computer. The difference is similar to that between Audio CD and CD-ROM. DVD-ROM also includes future variations that are recordable one time (DVD-R) or many times (DVD-RAM). Most people expect DVD-ROM to be initially much more successful than DVD-Video. Most new computers with DVD-ROM drives can also play DVD-Videos (see 6.1).

There's also a DVD-Audio format. The technical specifications for DVD-Audio are not yet finalized.

[1.2] What are the features of DVD-Video?

  • Over 2 hours of high-quality digital video (over 8 on a double-sided, dual-layer disc).
  • Support for widescreen movies on standard or widescreen TVs (4:3 and 16:9 aspect ratios).
  • Up to 8 tracks of digital audio (for multiple languages, DVS, etc.), each with as many as 8 channels.
  • Up to 32 subtitle/karaoke tracks.
  • Automatic "seamless" branching of video (for multiple story lines or ratings on one disc).
  • Up to 9 camera angles (different viewpoints can be selected during playback).
  • Menus and simple interactive features (for games, quizzes, etc.).
  • Multilingual identifying text for title name, album name, song name, cast, crew, etc.
  • "Instant" rewind and fast forward, including search to title, chapter, track, and timecode.
  • Doubles as a frisbee if the movie sucks.
  • Durability (no wear from playing, only from physical damage).
  • Not susceptible to magnetic fields. Resistant to heat.
  • Compact size (easy to handle, store, and ship; players can be portable; replication is cheaper).
  • Noncomedogenic.

Note: Most discs do not contain all features (multiple audio/subtitle tracks, seamless branching, parental control, etc.). Some discs may not allow searching or skipping.

Most players support a standard set of features:

  • Language choice (for automatic selection of video scenes, audio tracks, subtitle tracks, and menus).*
  • Special effects playback: freeze, step, slow, fast, and scan (no reverse play or reverse step).
  • Parental lock (for denying playback of discs or scenes with objectionable material).*
  • Programmability (playback of selected sections in a desired sequence).
  • Random play and repeat play.
  • Digital audio output (PCM stereo and Dolby-Digital).
  • Compatibility with audio CDs.

* Must be supported by additional content on the disc.

Some players include additional features:

  • Component (YUV or RGB) output for highest-quality picture.
  • Compatibility with Video CDs.
  • Six-channel analog output from internal audio decoder.
  • Compatiblity with laserdiscs and CDVs.
  • Reverse single frame stepping.
  • RF output (for TVs with no direct video input).
  • Multilingual on-screen display.

[1.3] What's the quality of DVD-Video? Why do some demos look so bad?

DVD has the capability to produce near-studio-quality video and better-than-CD-quality audio. DVD is vastly superior to videotape and generally better than laserdisc (see 2.8.). However, quality depends on many production factors. Until compression experience and technology improves we will occasionally see DVDs that are inferior to laserdiscs. Also, since large amounts of video have already been encoded for Video CD using MPEG-1, a few low-budget DVDs will use that format (which is no better than VHS) instead of higher-quality MPEG-2.

DVD video is compressed from digital studio master tapes to MPEG-2 format. This "lossy" compression removes redundant information (such as areas of the picture that don't change) and information that's not readily perceptible by the human eye. The resulting video, especially when it is complex or changing quickly, may sometimes contain "artifacts" such as blockiness, fuzziness, and video noise depending on the processing quality and amount of compression. At average rates of 3.5 Mbps (million bits/second), compression artifacts may be occasionally noticeable. Higher data rates can result in higher quality, with almost no perceptible difference from the original master at rates above 6 Mbps. As MPEG compression technology improves, better quality is being achieved at lower rates.

Video from DVD sometimes contains visible artifacts such as color banding, blurriness, blockiness, fuzzy dots, shimmering, missing detail, and even effects such as a face which "floats" behind the rest of the moving picture. It's important to understand that the term "artifact" refers to anything that was not originally present in the picture. Artifacts are sometimes caused by poor MPEG encoding, but artifacts are more often caused by a poorly adjusted TV, bad cables, electrical interference, sloppy digital noise reduction or picture enhancement, poor film-to-video transfer, film grain, player faults, disc read errors, etc. Most DVDs have few or no visible MPEG compression artifacts. If you think otherwise, you are misinterpreting what you see.

Some early DVD demos were not very good, but this is not an indication that DVD quality is bad, since other demos show no artifacts or other problems. Bad demos are simply an indication of how bad DVD can be if not properly processed and correctly reproduced. Many demo discs were rushed through the encoding process in order to be distributed as quickly as possible. Contrary to common opinion, and as stupid as it may seem, these demos are not carefully "tweaked" to show DVD at its best. In-store demos should be viewed with a grain of salt, since most salespeople are incapable of properly adjusting a television set. Most TVs have the sharpness set too high for the clarity of DVD. This exaggerates high-frequency video and causes distortion, just as the treble control set too high for a CD causes it to sound harsh. Many DVD players output video with a black-level setup of 0 IRE (Japanese standard) rather than 7.5 IRE (US standard). On TVs that are not properly adjusted this can cause some blotchiness in dark scenes. DVD video has exceptional color fidelity, so muddy or washed-out colors are almost always a problem in the display, not in the DVD player or disc.

DVD audio quality is excellent. One of DVD's audio formats is LPCM (linear pulse code modulation) with sampling sizes and rates higher than audio CD. Alternatively, audio for most movies is stored as discrete multi-channel surround sound using Dolby Digital audio compression similar to the surround sound formats used in theaters. As with video, audio quality depends on how well the processing and encoding was done. In spite of compression, Dolby Digital is close to CD quality.

The final assessment of DVD quality is in the hands of consumers. Most viewers consistently rate it better than laserdisc, but no one can guarantee the quality of DVD, just as no one should dismiss it based on demos or hearsay. In the end it's a matter of individual perception.

[1.4] What are the disadvantages of DVD?

  • It will take years for movies and software to become widely available.
  • It can't record (yet). (See 1.14 and 4.3)
  • It has built-in copy protection and regional lockout. (See 1.11 and 1.10)
  • It uses digital compression. Poorly compressed audio or video may be blocky, fuzzy, harsh, or vague. (See 1.3)
  • The audio downmix process for stereo/Dolby Surround can reduce dynamic range. (See 3.6)
  • It doesn't fully support HDTV. (See 2.9)
  • Some DVD players and drives may not be able to read CD-Rs. (See 2.4.3)
  • First-generation DVD players and drives can't read DVD-RAM discs. (See 4.3)
  • Current players can't play in reverse at normal speed.

[1.5] What DVD players and drives are available?

Some manufacturers originally announced that DVD players would be available as early as the middle of 1996. These predictions were woefully optimistic. Delivery was initially held up for "political" reasons of copy protection demanded by movie studios, but was later delayed by lack of titles.

Available players:

  • Japan (Region 2)
    • Panasonic: A-100, 79,800 yen; A-300, 98,000 yen (Nov 1996); DVD-A350, 94,000 yen; DVD-K500, 110,000 yen (Nov 97); DVD-A450, 100,000 yen (Dec 10, 97). YPbPr component out, 6-ch DD, 96 kHz 24-bit audio.
    • Toshiba: SD-3000, 77,000 yen (Nov 96); SD-K310, 89,000 yen (Jun 97)
    • Sanyo (Toshiba-made): (Dec 96).
    • Pioneer: DV-7, 83,000 yen; DVL-9, 133,000 yen; DVD-K800, 120,000 yen; DVK-1000, 248,000 yen; DV-F21 (Dec 96)
    • Hitachi (Pioneer-made): (Dec 96)
    • Akai: DV-P1000, 65,000 yen (Apr 97)
    • Sony: DVP-S7000, 110,000 yen (Mar 97); DVP-S3000, 79,000 yen. (?, 97). YPbPr component out.
    • Victor: XV-1000, 93,000 yen (Apr 97); XV-D2000, 115,000 yen. (Dec? 97). YPbPr component out, 6-ch DD.
  • Korea (Regions 3 and 5)
    • Samsung (Toshiba-made): Nov 96.
    • LG (Goldstar): Nov 96.
  • US (Region 1)
    • Panasonic: A-100, $600; A-300, $750 (Feb 97)
    • Toshiba: SD-2006, $600; SD-3006, $750 (Mar 1997); SD-2107, $600; SD-3107 (Aug 97).
    • Denon (Matsushita + Denon audio): DVD-2000, $800 (Mar 97)
    • Sony: DVP-S7000, $1000 (Apr 97); DVP-S3000 (Oct 97)
    • RCA (Matsushita-made): RC5200P, $500; RC5500P, $700 (Apr 97)
    • Proscan (Matsushita-made): PS8600P, $750; (same circuitry as RCA5500P) (Apr 97)
    • Mitsubishi (Toshiba-made): DD-1000, $700 (Apr 1997)
    • Philips/Magnavox: DVD 400AT, $550 (May 97); 420AT, $650 (Oct 97).
    • JVC: XV1000, $600 (Jun 97)
    • Samsung: DVD905, $750 (Sep 97)
    • Onkyo (Toshiba-made): DVD-7, $1000 (Fall 97)
    • Marantz (Toshiba-made): DVD810.
    • Yamaha (Matushita-made): DVD-1000 (Fall 97).
    • Zenith (Toshiba-made): DVD2000 (Fall 97).
    • Harman Kardon: HDV-715 (Fall 97).
    • Faroudja: DV-1000, $5500 (modified Toshiba 3006) (Fall 97)
    • Pioneer: DV-500, $600; DVL-700, $1000; DVL-90, $1750 (Feb 97); DVL-909, $1100 (LD/DVD) (Jan 98); DV-606D, $700 (24-bit 96 kHz) (Jan 98).
  • Europe (Region 2)
    • Panasonic: A-100EC, 1300DM; A-300EC, 1400DM (Mar 97); A-350EC, 1500DM (6-channel MPEG-2 & DD) (Jan 98)
    • Thomson (Matsushita-made): France, 4990 francs (Mar 97)
  • Asia (Region 3)
    • Panasonic: DVD-A130; DVD-A330.
    • Pioneer: DVL-505; DVL-909 (DVD/LD combo) (both NTSC only).
    • Philips: DVD-840 (=Toshiba SD-K310).
    • Sony: DVP-S7000 (May 97)
  • Australia (Region 4)
    • Panasonic: DVD-A130; DVD-A330; DVD-A300; DVD-A350 (6-channel MPEG-2) (Dec 97)
    • Sony: DVP-S7000

Projected player releases:

  • Japan (Region 2)
    • Toshiba: 2 portable players, 75,000 yen each (Nov 97).
    • Philips: Spring 98.
    • Panasonic: DVD-L10 portable player (Spring 98).
    • Sony: DVP-S501D, 88,000 yen; DVP-M30 (both 96/24 audio) (April 98)
    • Pioneer: DV-S9, 190,000 yen (96/24 audio); DVL-909, 128,000 yen (DVD/LD); DV-505, 69,800 yen; DVL-K88 148,000, yen (DVD/LD + karaoke).
    • Toshiba SD-2100(N).
  • US (Region 1)
    • Akai: DV-P1000.
    • Meridian: 586, $3500!.
    • Panasonic: DVD-A110, DVD-A310, DVD-A510 (all DTS-compatible); DVD-A350, ~$750; DVD-A450, ~$825 DVD-K500, ~$900 (Early 1998); DVD-L10, $1300 (portable) (Spring 98).
    • Kenwood: January 1998.
    • Runco: SAR-200, $15,000 (200-disc changer, THX-certified) (Jan 98).
    • Sony: DVP-S300, $500; DVP-S500D, $600 (Spring 98); DVP-C600D (5-disc changer) (Summer 98).
    • Denon: DVD-3000, $899 (DTS-compatible) (Apr 98).
    • Pioneer: DV-505, $500 (May 98).
    • Onkyo: DV-S501, $850 (Summer 98).
    • JVC: XV-D2000BK (24b/96kHz).
    • Fisher: DVD-60, $2,400 (60-disc DVD/DVD-ROM changer).
    • Hyundai, Goldstar, Hitachi (Pioneer-made), Runco (modified Pioneer), Sharp: No date.
    • Unity Motion: No date (progressive scan!).
  • Europe (Region 2)
    • JVC: Summer 98?
    • Kenwood: August in Germany (LZ-25).
    • Sony: DVP–S715, DVP-S315 (both have 24/96 audio, MPEG-2 audio, RGB SCART) (Spring '98).
    • Philips: Spring 1998 (DVD 730, DM 1500; DVD 930, DM 1700).
    • Hitachi, Pioneer, Toshiba: Spring 1998.
    • Grundig: GDV 100 G.
  • Asia (Region 3)
    • Toshiba: ?.
  • Australia/New Zealand (Region 4)
    • ?

Fujitsu supposedly released the first DVD-ROM-equipped computer on Nov. 6 in Japan. Toshiba released a DVD-ROM-equipped computer and a DVD-ROM drive in Japan in early 1997 (moved back from December which was moved back from November). DVD-ROM drives from Toshiba, Pioneer, Panasonic, Hitachi, and Sony began appearing in sample quantities as early as January 1997, but none were to be available before May. Creative Labs' $499 PC-DVD upgrade kit (Matsushita drive, A/V decoder board; Warner DVD-V sampler) went on sale in the U.S. in April for $500. Samsung drives (and PCs with drives) were available in Korea in January. Hi-Val's $799 PC-DVD upgrade kit (Toshiba drive, Quadrant decoder; 6 DVD-ROMS including Silent Steel, Daedalus Encounter, and Xiphias Encyclopedia Electronica) was scheduled for May, as was Diamond Multimedia's $599 kit. STB Systems DVD Theater Upgrade Kit was be available in July for $699. DynaTek announced a $649 upgrade kit with 6 titles. Philips drives will be available in the 2nd quarter. LG Electronics drives were be available in July. Toshiba's Infinia DVD-ROM-equipped PC become available Summer 1997. Compaq and Sony DVD-PCs are delayed. Creative's new "Encore" 2x DVD-ROM kit is available for $380. Hi-Val's 2nd-generation kit is also $380. E4's CoolDVD upgrade kit for Macintoshes is available for $499 in April 1998.
For drive details see

Note: If you buy a player or drive from outside your country (e.g., a Japanese player for use in the US) you may not be able to play region-locked discs on it. (See 1.10.)

[1.6] What DVD titles are available?

As with hardware, rosy predictions of hundreds of movie titles for Christmas of 1996 failed to materialize. Only a handful of DVD titles, mostly music videos, were available in Japan for the November 1996 launch of DVD. Actual feature films began to appear in December. By April there were over 150 titles in Japan. Movies appeared in the US in March of 1997. Currently (Apr 1998) there are about 800 titles available in the US and over 1200 worldwide. Compared to other launches (CD, LD, etc.) this is a huge number. Almost 19,000 discs were purchased in the first two weeks of the US launch -- more than expected. InfoTech predicted over 600 titles by the end of 1997 and more than 8,000 titles by 2000. By December 1997, over 1 million individual DVD discs were shipped.

A concerted launch of DVD hardware and software in Europe is planned for the second quarter of 1998. Over 100 titles are expected to be available by March, with over 250 available by the end of 1998. Time Warner's official launch of DVD in Australia (region 4) is planned for Easter of 1998.

For a complete list of titles available in the US and Canada, see <>, and for titles in Japan and Europe see <>. Another extensive list of US titles is at <>. New release lists and announcements are also available at <>

Concorde Video released a PAL-format "12 Monkeys" in Germany at the end of March. They were threatened by Philips with a lawsuit for not including a multichannel MPEG track, but the issue is now resolved (see 3.6).

DVD-ROM software will slowly appear. Approximately 50% of CD-ROM producers have announced intentions to develop for DVD-ROM. See 6.2 for a list. Many initial DVD-ROM titles are only be available as part of a hardware or software bundle until the market grows larger. IDC expects that over 13 percent of all software will be available in DVD-ROM format by the end of 1998. In one sense, DVD-ROMs are simply larger faster CD-ROMs and will contain the same material. But DVD-ROMs can also take advantage of the high-quality video and multi-channel audio capabilities being added to many DVD-ROM-equipped computers.

[1.7] How much do players and drives cost?

Mass-market DVD movie players currently list for $400 and up. (See 1.5 for models and prices.) Within a few years they may approach VCR prices. InfoTech predicts prices will be as low as $250 by the year 2000, and below $150 by 2005.

DVD-ROM drives and upgrage kits for computers sell for around $200 to $600. (OEM drive prices are under $200.) Prices are expected to drop quickly to current CD-ROM drive levels.

[1.8] How much do discs cost?

It varies, but most DVD movies list for $25 to $30 with street prices between $18 and $25, even those with supplemental material. Some new releases are initially priced for rental (near $80, the same as VHS), others are as low as $12.

DVD-ROMs will initially be slightly more expensive than CD-ROMs since there is more on them, they cost more to replicate, and the market is smaller. But once production costs drop and the installed base of drives grow, DVD-ROMs will cost about the same as CD-ROMs today.

[1.9] How quickly will DVD become established?

Not as fast as generally predicted, but faster than videotape, laserdisc, and CD. By the end of 1997 over 500,000 DVD-Video players shipped worldwide. 349,482 of these were in the US (with about 200,000 actually sold into homes). About ?? video titles were available worldwide, with ?? million copies shipped. About 600 video titles were available in the US, with over 5 (?) million copies shipped and about 2 million sold. Around 330,000 DVD-ROM drives were shipped worldwide with about 1 million bundled DVD-ROM titles. Only 60 DVD-ROM titles were available by the end of 1997.

Here are some predictions:

  • Toshiba (1996): 100,000 to 150,000 DVD-Video players will be sold in Japan between Nov. 1 and Dec. 31, 1996, and 750,000-1 million by Nov. 1, 1997. (Actual count of combined shipments by Matsushita, Pioneer, and Toshiba was 70,000 in Oct-Dec 1996.)
  • Pioneer (1996): 400,000 DVD-Video players in 1996, 11 million by 2000. 100,000 DVD-Audio players in 1996, 4 million by 2000.
  • InfoTech (1996): 820,000 DVD-Video players in first year, 80 million by 2005.
  • CEMA (1997): 400,000 DVD-Video players in U.S. in 1997, 1 million in 1998.
  • Time-Warner (1996): 10 million DVD players in the U.S. by 2002.
  • Paul Kagan (1997): 800,000 DVD players in the U.S. in 1997, 10 million in 2000, and 40 million in 2006 (43% penetration). 5.6 million discs sold in 1997, 172 million discs in 2000, and 623 million in 2006.
  • C-Cube (1996): 1 million players and drives in 1997.
  • BASES: 3 million DVD-Video players sold in first year, 13 million sold in 6th year.
  • Dataquest (1997): over 33 million shipments of DVD players and drives by 2000.
  • Philips (1996): 25 million DVD-ROM drives worldwide by 2000 (10% of projected 250 million optical drives).
  • Pioneer (1996): 500,000 DVD-ROM drives sold in 1997, 54 million sold in 2000.
  • Toshiba (1996): 120 million DVD-ROM drives in 2000 (80% penetration of 100 million PCs). Toshiba says they will no longer make CD-ROM drives in 2000.
  • IDC (1997): 10 million DVD-ROM drives sold in 1997, 70 million sold in 2000 (surpassing CD-ROM), 118 million sold in 2001. Over 13% of all software available on DVD-ROM in 1998. DVD recordable drives more than 90% of combined CD/DVD recordable market in 2001.
  • AMI (1997): installed base of 7 million DVD-ROM drives by 2000.
  • Intel (1997): 70 million DVD-ROM drives by 1999 (sales will surpass CD-ROM drives in 1998).
  • SMD (1997): 100 million DVD-ROM/RAM drives shipped in 2000.
  • Microsoft (Peter Biddle, 1997): 15 million DVD-PCs sold in 1998, 50 million DVD-PCs sold in 1999.
  • Forrester Research (1997): U.S. base of 53 million DVD-equipped PCs by 2002. 5.2% of U.S. households (5 million) will have a DVD-V player in 2002; 2% will have a DVD-Audio player.
  • Yankee Group (Jan 1998): 650,000 DVD-Video players by 1998, 3.6 million by 2001. 19 million DVD-PCs by 2001.
  • InfoTech (Jan 1998): 20 million DVD-Video players worldwide in 2002, 58 million by 2005. 99 million DVD-ROM drives worldwide in 2005. No more than 500 DVD-ROM titles available by the end of 1998. About 80,000 DVD-ROM titles available by 2005.

For comparison, there are about 700 million audio CD players and 160 million CD-ROM drives worldwide in 1997. 1.2 billion CD-ROMs were shipped worldwide in 1997 from a base of about 46,000 different titles. There are about 80 million VCRs in the U.S. (89% of households) and about 400 million worldwide. There are about 250 million TVs in the US and 1.2 billion worldwide. Estimated 1997 U.S. sales: 7.7 million VCRs, 900,000 projection televisions.

[1.10] What are "regional codes," "country codes," or "zone locks"?

Motion picture studios want to control the home release of movies in different countries because theater releases aren't simultaneous (a movie may come out on video in the U.S. when it's just hitting screens in Europe). Also, studios sell distribution rights to different foreign distributors and would like to guarantee an exclusive market. Therefore they have required that the DVD standard include codes which can be used to prevent playback of certain discs in certain geographical regions. Each player is given a code for the region in which it's sold. The player will refuse to play discs which are not allowed in that region. This means that discs bought in one country may not play on players bought in another country.

Regional codes are entirely optional. Discs without codes will play on any player in any country. It's not an encryption system, it's just one byte of information on the disc that the player checks. Some studios have announced that only their new releases will have regional codes, but so far almost all releases play in only one region.

There are 6 regions (also called "locales"). Players and discs are identified by the region number superimposed on a world globe. If a disc plays in more than one region it will have more than one number on the globe.
1: Canada, U.S., U.S. Territories
2: Japan, Europe, South Africa, Middle East (including Egypt)
3: Southeast Asia, East Asia (including Hong Kong)
4: Australia, New Zealand, Pacific Islands, Central America, South America, Caribbean
5: Former Soviet Union, Indian Subcontinent, Africa (also North Korea, Mongolia)
6: China
(See the map at <>.)

Some players, such as the early Sony model, can be modified to play discs regardless of their regional codes. This will probably void the warranty.

Regional codes also apply to DVD-ROM systems, but are allowed for use only with DVD-Video discs, not DVD-ROM discs containing computer software. (See 1.11 below for more details). Operating systems including upcoming versions of Windows and MacOS will check for regional codes before playing movies from a DVD-Video. Some DVD-ROM kits let you change the region code a limited number of times. It's likely that regional codes will apply to DVD-Audio.

[1.11] What are the copy protection issues?

There are four forms of copy protection used by DVD:

1) Analog CPS (Macrovision)
Videotape (analog) copying is prevented with a Macrovision 7.0 or similar circuit in every player. The general term is APS (Analog Protection System). Computer video cards with composite or s-video (Y/C) output must also use APS. Macrovision adds a rapidly modulated colorburst signal ("Colorstripe") along with pulses in the vertical blanking signal ("AGC") to the composite video and s-video outputs. This confuses the synchronization and automatic-recording-level circuitry in 95% of consumer VCRs. Unfortunately, it can degrade the picture, especially with old or nonstandard equipment. Macrovision may show up as stripes of color, distortion, rolling, black & white picture, and dark cycling. Macrovision creates severe problems for most line doublers. Macrovision is not present on analog component video output of early players, but is required on newer players such as the Sony S7000 (AGC only, since there is no burst in a component signal). The discs contain "trigger bits" in the header of each sector telling the player whether or not to enable Macrovision AGC, with the optional addition of 2-line or 4-line Colorstripe. This allows fine control over which sections are copy protected. The producer of the disc decides what amount of copy protection to enable and then pays Macrovision royalties accordingly (a few cents per disc). Just as with videotapes, some DVDs are Macrovision-protected and some aren't. (For a few Macrovision details see SGS/Thomson's video encoder datasheet at <>.)

Each disc also contains information specifying if the contents can be copied. This is a "serial" copy generation management system (CGMS) designed to prevent copies or copies of copies. The CGMS information is embedded in the outgoing video signal. For CGMS to work, the equipment making the copy must recognize and respect the CGMS. The analog standard (CGMS/A) encodes the data on NTSC line 21. The digital standard (CGMS/D) is not yet finalized, but will apply to digital connections such as IEEE 1394/Firewire. See 4) below.

3) Content Scrambling System (CSS)
Because of the potential for perfect digital copies, paranoid movie studios forced a deeper copy protection requirement into the DVD-Video standard. Content Scrambling System (CSS) is a form of data encryption to discourage reading media files directly from the disc. Most players have a decryption circuit that decodes the data before displaying it. No unscrambled digital output is allowed until work in progress for secure digital connections is finished. On the computer side, DVD-ROM drives and video display/decoder hardware or software exchange encryption keys so that the video is decrypted just before being displayed by the encoder. This means that many DVD-ROM drives and video display boards have extra hardware (and cost) for movie copy protection. In 1999, all DVD-ROM drives will be required to support regional management in conjunction with CSS. Some drives may allow the user to reset the region a limited number of times; other drives will self-program after a certain number of movies have been played. Makers of equipment used to display DVD-Video (drives, chips, display boards, etc.) must license CSS. There is no charge for a CSS license, but it's currently a lengthy process, so it's recommended that interested parties apply as soon as possible. Near the end of May 1997, CSS licenses were finally granted for software decoding.

4) Digital CPS
In order to provide for digital connections between components without allowing perfect digital copies, a digital copy protection system has been developed, focused on IEEE 1394/FireWire. The draft proposal was made by Intel, Sony, Hitachi, Matsushita, and Toshiba in Feb. 1998. Content is marked with standard CGMS flags of "copy never" or "copy once." Devices that are digitally connected, such as a DVD player and a digital TV, will exchange keys and authentication certificates to establish a channel. The DVD player will encrypt the encoded video signal as it sends it to the receiving device, which must decrypt it. Digital display devices will be able to receive and display all data. Digital recording devices will only be able to receive data which is not marked "copy never," and they must change the CGMS flags to zero copies if the source is marked for one copy. Digital CPS is designed for the next generation of digital TVs and digital video recorders. It will require new DVD players with digital connectors (such as those provided on DV cameras and decks). These new products probably won't appear before mid 1999. Since the encryption is done by the player, no changes are needed to the existing disc format.

Movie studios and consumer electronics companies want to make it illegal to defeat DVD copy protection, and are pursuing legislation in the U.S. and other countries. A co-chair of the legal group of the copy protection committee stated, "in the video context, the contemplated legislation should also provide some specific assurances that certain reasonable and customary home recording practices will be permitted, in addition to providing penalties for circumvention." It's not at all clear how this might be "permitted" by a player.

CSS is allowed for DVD-video content only. Of course, since a DVD-ROM can hold any form of computer data, any desired encryption scheme can be implemented

The first three forms of copy protection are optional for the producer of a disc. Movie decryption is also optional for hardware and software playback manufacturers: a player or computer without decryption capability will only be able to play unencrypted movies. Digital CPS is performed by the DVD player, not by the disc developer.

These copy protection schemes are designed only to guard against casual copying (which the studios claim causes billions of dollars in lost revenue). The goal is to "keep the honest people honest." Even the people who developed the copy protection standards admit that they won't stop well-equipped pirates. There are inexpensive devices that defeat analog copy protection, but Macrovision claims none of the devices are effective against the new Colorstripe feature (yet).

Macrovision and DigiMarc have proposed a watermark process for DVD, which permanently marks each video frame with visually undetectable information. This can be recognized by video equipment to prevent copying, even when the video is transmitted digitally. New players and other equipment will be required to support watermarking. It's possible to make new watermarked discs compatible with existing players, but movie studios will probably not allow it.

[1.12] What about DVD-Audio or Music DVD?

The DVD Consortium has decided to seek additional input from the music industry before defining the DVD-Audio format. A draft standard was released by DVD Forum's Working Group 4 (WG4) in January 1998 (see 3.6). DVD-Audio products might show up in 1999 at the earliest. If the final specification includes features or formats not present in the current DVD specification, existing DVD players may not be able to play new DVD-Audio discs.

Sony and Philips are proposing a Super Audio CD format based on Direct Stream Digital (DSD). SACD will compete with WG4's DVD-Audio proposal. SACD provides "legacy" discs that will have two layers, one that woill play in existing CD players, plus a high-density layer for DVD-Audio players. Sony expects to release version 0.9 of the SACD spec in March 1998. SACD technology will be available to existing CD licensees at no additional cost.

There are rumors that the DVD Consortium is pushing for an 8 cm (CD-single) size, while the audio industry wants a 12 cm size. (The existing DVD physical spec allows both sizes.) Organizations such as Acoustic Renaissance for Audio (ARA) have recommended lossless compressed PCM that's more appropriate for studio work and archiving. Dolby Digital rates may be allowed to go higher than the 448-kbps limit of DVD-Video, or even the 640 kbps limit of most current decoders.

The music industry is also requesting an "embedding signalling" or "digital watermark" copy protection feature. This uses pit signal processing technology to apply a digital signature and optional encryption keys to the audio in the form of supposedly inaudible noise so that new equipment will recognize copied audio and refuse to play it. Audiophiles claim this degrades the audio.

In the meantime, the DVD-Video standard includes surround sound audio and better-than-CD audio (see 3.6). Pioneer is developing audio-only players based on the audio portion of DVD-Video.

[1.13] Which studios are supporting DVD?

Warner, Columbia TriStar, MGM, Polygram, Paramount, Disney, Fox, and others are releasing movies on DVD (see 6.2 for a full list; see 1.6 for movie info). Paramount and Fox have officially announced support only for Divx, but they are known to be working on regular DVDs.

[1.14] Can DVD record from VCR/TV/etc?

Short Answer: No. (Not in this century.)

Long answer: The minimum requirement for reproducing audio and video on DVD is an MPEG video stream and a PCM audio track. (Other streams such as Dolby Digital audio, MPEG audio, and subpicture are not necessary for the simplest case.) Basic DVD control codes are also needed. At the moment it's difficult in real time to encode the video and audio, combine them with DVD-V info, and write the whole thing to DVD. Even if you could do all this in a home recorder, it would be extremely expensive. Prices for DVD production systems are dropping from millions of dollars to thousands of dollars, but they won't be in the <$500 range for home use for several years yet. In June 1997, Hitachi demonstrated a home DVD video recorder containing a DVD-RAM drive, a hard disk drive (as a buffer), two MPEG-1 encoders, and an MPEG-2 decoder. No production date was mentioned. It's possible the first home DVD recorders will require a digital source of already-compressed audio and video, such as DBS.

Other obstacles: Price of blank discs initially will be $30 and up. The first generation of recordable media will hold less than 3/4 as much as prerecorded discs. Realtime compression requires higher bit rates for decent quality, lowering capacity even more. MPEG-2 compression works much better with high-quality source, so recording from VHS or broadcast/cable may not give very good results (unless the DVD recorder has prefilters, which raises the cost).

Don't be confused by DVD-R, which came out in Sep 1997 for $17,000, or DVD-RAM, which will be available soon for about $800, or other recordable variations of DVD (see 4.3). These can record data, but to create full-featured DVD-Videos requires additional hardware and software to do video encoding (MPEG), audio encoding (Dolby Digital, MPEG, or PCM), subpicture encoding (run-length-compressed bitmaps), still frame encoding (MPEG), navigation and control data generation, and multiplexing. And since this can't yet be done in real time, you'd also need a 5 to 9 GB hard drive to premaster the data to.

Some people believe that recordable DVD-Video will never be practical for consumers to record TV shows or home videos, since digital tape is more cost effective. On the other hand, digital tape lacks many of the advantages of DVD such as seamless branching, instant rewind/fast forward, instant search, and durability, not to mention the coolness of small shiny discs. So once the encoding technology is fast and cheap enough, and the blank discs are cheap enough, recordable DVD may be a reality. It will be an interesting contest between DVD and digital video tape (DV). DV is out already, but decks cost $4,000.

[1.15] What happens if I scratch the disc? Aren't discs too fragile to be rented?

Most scratches will cause minor channel data errors that are easily corrected. A common misperception is that a scratch will be worse on a DVD than on a CD because of higher storage density and because video is heavily compressed. DVD data density (say that fast ten times!) is physically four times that of CD-ROM, so it's true that a scratch will affect more data. But DVD error correction is at least ten times better and more than makes up for the density increase. It's also important to realize that MPEG-2 and Dolby Digital compression are partly based on removal or reduction of imperceptible information, so decompression doesn't expand the data as much as might be assumed. Major scratches may cause uncorrectable errors that will cause an I/O error on a computer or show up as a momentary glitch in DVD-Video picture. There are many schemes for concealing errors in MPEG video, which may be used in future players (see section D.12 of <>).

The DVD computer advisory group specifically requested no mandatory caddies or other protective carriers. Consider that laserdiscs, music CDs, and CD-ROMs are likewise subject to scratches, but many video stores and libraries rent them. Major chains such as Blockbuster and West Coast Entertainment rent DVDs in many locations. So far most reports of rental disc performance are positive. A nice list of DVD rental outlets is at <>.

[1.16] VHS is good enough, why should I care about DVD?

The primary advantages of DVD are quality and extra features (see 1.2). DVD will not degrade with age or after many playings like videotape will (which is an advantage for parents with kids who watch Disney videos twice a week!). This is the "collectability" factor present with CDs vs. cassette tapes.

If none of this matters to you, then VHS probably is good enough.

[1.17] Is the packaging different from CD?

Manufacturers are worried about customers assuming DVDs will play in their CD player, so they would like the packaging to be different. There are a number of DVD packages such as the "keep case" and Time Warner's "Snapper" that are about as wide as a CD jewel box and about as tall as a VHS cassette box. However, no one is being forced to use a larger package size and many companies will undoubtedly use standard jewel cases. It remains to be seen if any package becomes standard, especially for DVD-ROM.

[1.18] What's a dual-layer disc? Will it work in all players?

A dual-layer disc has two layers of data, one of them semi-transparent. Since both layers are readable from the same side, a dual-layer disc can hold almost twice as much as a single-layer disc, for over 4 hours of video (see 3.3 for more details). Many dual-layer discs are currently available (such as Contact, Goldeneye, Species, Raging Bull, and Rain Man). Initially only a few replication plants could make dual-layer discs, but most plants now have the capability. The second layer can either have a "PTP" track that runs in parallel to the first track (for independent data or special switching effects), or an "OTP" tracks that runs opposite to the first track; that is the pickup head reads out from the center on the first track then in from the outside on the second track. This is designed to provide continuous video across both layers. There's no guarantee that the switch between layers will be seamless. Non-seamless switches cause the video to freeze for less than half a second on most players but up to 4 seconds on some. The "seamlessness" depends as much on the way the disc is prepared as on the design of the player. OTP is also called RSDL (Reverse-Spiral Dual Layer). The advantage of OTP (RSDL) is that longer movies can use higher data rates for better quality than with a single layer. See 1.26 for layer change details.

All DVD players and drives can read dual-layer discs -- it's required by the spec. All players and drives also play double-sided discs if you flip them over. No manufacturer has announced a model that will play both sides. The added cost is probably not justifiable since discs can hold over 4 hours of video on one side by using two layers. (Early discs used two sides because dual-layer production was not widely supported. This should no longer be a problem.) Pioneer LD/DVD players can play both sides of an LD, but not a DVD. (See 2.9 for note on reading both sides simultaneously.)

There are various ways to recognize dual-layer discs: 1) the gold color, 2) a menu on the disc for selecting the widescreen or letterbox version, 3) two serial numbers on one side.

[1.19] Is DVD-Video a worldwide standard? Does it work with NTSC, PAL, and SECAM?

DVD-V has the same NTSC vs. PAL problem as videotape and laserdisc. The MPEG video on DVD is stored in digital format, but it's formatted for one of two mutually incompatible television systems: 525/60 (NTSC) or 625/50 (PAL/SECAM). There are three differences between discs intended for playback on different systems: picture size and pixel aspect ratio (720x480 vs. 720x576), display frame rate (29.97 vs 25), and surround audio (Dolby Digital vs. MPEG). (See 3.4 and 3.6 for details.) Video from film is usually stored at 24 frames/sec but is preformatted for one of the two display rates. Movies formatted for PAL display are usually sped up by 4%, so the audio must be adjusted accordingly before being encoded.

Some players will only play NTSC discs, some players will only play PAL discs, and some will play both. Most European players play both. These multi-standard players output NTSC from a 525/60 disc and PAL from a 625/50 disc. This requires two TVs or a multi-standard TV. Some players partially convert NTSC to 60 Hz PAL, which requires a 60 Hz PAL TV. It's also possible to make a standards-converting player that will output standard NTSC from a 625/50 disc or standard PAL from a 525/60 disc, but no such players have been announced.

A producer can choose to include additional video and audio --at the expense of playing time-- so that all formats are covered. It's unclear if players will be able to automatically recognize and play the correct video track. Of course it's always possible to put 525/60 video on one side of the disc and 625/50 on the other. Most studios so far are including Dolby Digital tracks along with the MPEG audio tracks on their PAL discs.

There are actually three types of DVD players if you count computers. Most DVD playback software and hardware can play both NTSC and PAL video.

[1.20] What about animation on DVD? Doesn't it compress poorly?

Some people claim that animation, especially hand-drawn cell animation such as cartoons and anime, does not compress well with MPEG-2 or even ends up larger than the original. Other people claim that animation is simple so it compresses better. Neither is true.

Supposedly the "jitter" between frames caused by differences in the drawings or in their alignment causes problems. An animation expert at Disney pointed out that this doesn't happen with modern animation techniques. And even if it did, the motion estimation feature of MPEG-2 would compensate for it.

Because of the way MPEG-2 breaks a picture into blocks and transforms them into frequency information it can have a problem with the sharp edges common in animation. This loss of high-frequency information can show up as "ringing" or blurry spots along edges (called the Gibbs effect). However, at the data rates commonly used for DVD this problem does not occur.

[1.21] Why do some discs require side flipping? Can't DVDs hold four hours per side?

Even though DVD's dual-layer technology (see 3.3) allows over four hours of continuous playback, some movies are split over two sides of a disc, requiring that the disc be flipped partway through. Most "flipper" discs exist because of producers who are too lazy to optimize the compression or make a dual-layer disc. Better picture quality is a lame excuse for increasing the data rate; in many cases the video will look better if carefully encoded at a lower bit rate. Lack of dual-layer production capability is also a lame excuse; in 1997 very few DVD plants could make dual-layer discs, but this is no longer the case. No players can automatically switch sides, but it's not needed since most movies less than 4 hours long can easily fit on one dual-layer (RSDL) side.

The following discs are "flippers." (Note: This is not the same as a disc with a widescreen version on one side and a pan & scan version or supplements on the other.)

  • Amadeus
  • The Best Years of Our Lives
  • The Color Purple
  • Dances with Wolves
  • Das Boot: The Director's Cut
  • Dawn of the Dead
  • An Evening of Yes Music Plus - Anderson Bruford Wakeman Howe
  • Gloria Estefan Live in Miami, the Evolution Tour
  • Goodfellas
  • The Green Berets
  • Into the Woods
  • JFK
  • Lawnmower Man: Special Edition
  • Live! At Knebworth
  • Loud and Live - Ozzy Osbourne
  • The Man Who Would Be King
  • Michael Collins
  • The Pelican Brief
  • The Right Stuff
  • Robin Hood Prince of Thieves
  • Rosewood
  • Seven
  • Sleepers
  • Spawn - The Animated Series
  • Stargate (Note: A dual-layer special edition of Stargate is planned for July 98)
  • A Time to Kill
  • The Unbearable Lightness of Being
  • The Wild Bunch
  • Woodstock

[1.22] Why is the picture squished, making things look too skinny?

Answer: RTFM. You are watching an anamorphic picture intended for display only on a widescreen TV. (See 3.5 for technical details). You need to go into the player's setup menu and tell it you have a standard 4:3 TV, not a widescreen 16:9 TV. It will then automatically letterbox the picture so you can see the full width at the proper proportions. In some cases you can change the aspect ratio as the disc is playing (by pressing the "aspect" button on the remote control. On Pioneer players, you have to stop the disc before you can change aspect.

[1.23] Do all videos use Dolby Digital (AC-3)? Do they all have 5.1 channels?

Most DVD-Video discs contain Dolby Digital soundtracks. However, it's not required. Some discs, especially those containing only audio, have PCM tracks. It's also possible for a 625/50 (PAL) disc to contain only MPEG audio, but so far MPEG audio is not widely used.

Don't assume that the "Dolby Digital" label is a guarantee of 5.1 channels. A Dolby Digital soundtrack can be mono, dual mono, stereo, Dolby Surround stereo, etc. For example, Blazing Saddles and Caddyshack are mono movies, so the Dolby Digital soundtrack on these DVDs has only one channel. Some DVD packaging has small lettering or icons under the Dolby Digital logo that indicates if there are 5.1 channels. In some cases, there are more than one Dolby Digital tracks: a 5.1-channel track and a track specially remixed for stereo Dolby Surround.

See 3.6 for more audio details.

[1.24] Can DVDs have laser rot?

Laserdiscs are subject to what's commonly called laser rot: the deterioration of the aluminum layer due to oxidation. The large size of laserdiscs makes them flexible, so that movement along the bond between sides can break the seal. Like laserdiscs, DVDs are made of two platters glued together, but DVDs are more rigid and use newer adhesives. Also, DVDs are molded from polycarbonate, which absorbs about ten times less moisture than the PMMA used for laserdiscs. It's too early to know for sure, but DVD's will probably have few or no laser rot problems.

[1.25] Which titles are pan & scan only? Why?

Some titles are available only in pan & scan because there was no letterbox or anamorphic transfer made from film. (See 3.5 for more info on pan & scan.) Since transfers cost $50,000 to $100,000, studios may not think a new transfer is justified. In some cases the original film or rights to it are no longer available for a new transfer. In the case of old movies, they were shot full frame so there is no widescreen version. The following DVD titles are pan & scan or full frame. A detailed list is also available at <>. A list of anamorphic titles is available at <>.

  • The Bodyguard
  • Bonnie & Clyde
  • Bridges of Madison County
  • Caddyshack
  • Casablanc
  • Chariots of Fire
  • Driving Miss Daisy
  • Grumpy Old Men
  • My Fellow Americans
  • Fly Away Home
  • Michael
  • Space Jam

[1.26] How do I make the subtitles on my Pioneer player go away?

On the remote control, press Subtitle, then either Clear or 0 (zero). No need to use the menus.

[1.27] What is a layer change? Where is it on specific discs?

Some movies over 2 hours long may be spread across two layers on a disc. When the player changes to the second layer, the video and audio may freeze for a moment. The length of the pause depends on the player and on the layout of the disc. The pause is not a defect in the player or the disc. See 1.18 for details.

Layer changes on RSDL discs:

  • A Night To Remember: ?
  • Amarcord: ?
  • Apollo 13: between chapter 16 and 17 (fade to black)
  • Cabaret: ?
  • Camelot: ?
  • Casino: ?
  • Cat On A Hot Tin Roof: ?
  • Contact: 1:00:34 (cut to fax from Hadden)
  • Dante's Peak: ?: ?
  • Doctor Zhivago: ?
  • Excalibur: ?
  • Far And Away: ?
  • Field Of Dreams: ?
  • Hard Boiled: ?
  • Heat: ?
  • Hercules: The Xena Trilogy: 25:04 in "The Gauntlet" (2nd feature, during sunrise)
  • How The West Was Won: ?
  • My Fair Lady: ?
  • Once Upon a Time in America: ?
  • Platoon: ?
  • Platoon: ?: ?
  • Pulp Fiction: ?
  • Rebel Without a Cause: ?
  • Scent Of A Woman: ?
  • Seven Samurai: ?
  • Short Cuts: ?
  • Spartacus: ?
  • Stargate: ?
  • Terminator 2: 1:19:45 (close up of knife in table)
  • The Deer Hunter: ?
  • The Devils Advocate: ?
  • The Dirty Dozen: ?
  • The English Patient: ?
  • The Good, the Bad, and the Ugly: 1:29:21 (Tuco asked if he'd like music)
  • The Great Escape: ?
  • The Shawshank Redemption: ?
  • Vertigo SE: ?
  • Waterworld: 0:58:54 (cut to boxes of SMEAT and VODKA)

[1.28] The disc says Dolby Digital. Why do I get 2-channel surround audio?

Some discs (many from Columbia TriStar) put 2-channel Dolby Surround audio on track one and 5.1-channel audio on track two. Unless you intervene, the player will play the default 2-channel track. Use the audio button on the remote or select the 5.1 track from the menu. (Note: The Sony 3000 has a feature to automatically select the first 5.1 track.)

Dolby Digital doesn't necessarily mean 5.1 channels. See 3.6.

[2] DVD's relationship to other products

[2.1] Will DVD replace VCRs?

Not any time soon. Recordable DVD is for computer data only, not television video (see 1.14). It will take a while before the size of the market drives costs down to VCR levels. However, DVD has many advantages over VCRs, including fundamentally lower technology cost for hardware and disc production (which is appealing to manufacturers), so if DVD is a commercial success it might replace many VCRs in fifteen to twenty years.

[2.2] Will DVD replace CD-ROM?

Yes. Some CD-ROM drive manufacturers plan to cease CD-ROM drive production after a few years in favor of DVD-ROM drives. Because DVD-ROM drives can read CD-ROMs, there is a compatible forward migration path.

[2.3] Can CD-R writers create DVDs?

No. DVD uses a smaller wavelength of laser to allow smaller pits in tracks that are closer together. The DVD laser must also focus more tightly and at a different level. In fact, a disc made on a current CD-R writer may not be readable by a DVD-ROM drive (see 2.4.3). It's unlikely there will be "upgrades" to convert CD-R drives to DVD-R, since this would probably cost more than purchasing a new DVD-R drive.

[2.4] Is CD compatible with DVD?

This is actually many questions with many answers:
[Note the differentiation between DVD (general case) and DVD-ROM (computer data).]

[2.4.1] Is CD audio (CD-DA) compatible with DVD?

Yes. All DVD players and drives will read audio CDs (Red Book). This is not actually required by the DVD spec, but so far all manufacturers have stated that their DVD hardware will read CDs. On the other hand, you can't play a DVD in a CD player. (The pits are smaller, the tracks are closer together, the data layer is a different distance from the surface, the modulation is different, the error correction coding is new, etc.)

[2.4.2] Is CD-ROM compatible with DVD-ROM?

Yes. All DVD-ROM drives will read CD-ROMs (Yellow Book). However, DVD-ROMs are not readable by CD-ROM drives.

[2.4.3] Is CD-R compatible with DVD-ROM?

Sometimes. The problem is that CD-Rs (Orange Book Part II) are "invisible" to DVD laser wavelength because the dye used in CD-Rs doesn't reflect the beam. Some first-generation DVD-ROM drives and many DVD players can't read CD-Rs. The common solution is to use two lasers at different wavelengths: one for reading DVDs and the other for reading CDs and CD-Rs. Variatons on the theme include Sony's "dual discrete optical pickup" with switchable pickup assmblies with separate optics, Samsung's "annular masked objective lens" with a shared optical path, Toshiba's similar shared optical path using an objective lens masked with a coating that's transparent only to 650-nm light, Hitachi's switchable objective lens assembly, and Matsushita's holographic dual-focus lens. Look for drives with the MultiRead label, which guarantees compatibility with CD-R and CD-RW media.

An effort to develop CD-R "Type II" media compatible with both CD and DVD wavelengths has been abandoned.

[2.4.4] Is CD-RW compatible with DVD?

Usually. CD-Rewritable (Orange Book Part III) has a lower reflectivity difference, requiring new automatic-gain-control (AGC) circuitry. CD-RW discs can't be read by most existing CD-ROM drives and CD players. The new "MultiRead" standard addresses this, and some DVD manufacturers have suggested they will support it. The optical circuitry in DVD-ROM drives and DVD players is usually able to read CD-RW discs, since CD-RW does not have the "invisibility" problem of CD-R (see 2.4.3).

[2.4.5] Is Video CD compatible with DVD?

Sometimes. It's not required by the DVD spec, but it's trivial to support the White Book standard since any MPEG-2 decoder can also decode MPEG-1 from a Video CD. Panasonic, RCA, Samsung, and Sony models play Video CDs. Japanese Pioneer models play Video CDs but American models don't. Toshiba players don't play Video CDs.

VCD resolution is 352x288 for PAL and 352x240 for NTSC. The way most DVD players and Video CD players deal with the difference is to chop off the extra lines or add blank lines. When playing PAL VCDs, the Panasonic and RCA NTSC players apparently cut 48 lines (17%) off the bottom. The Sony NTSC players apparently scale all 288 lines to fit.

Most DVD-ROM computers will be able to play Video CDs (with the right software), since its already possible with current-model CD-ROM computers.

Note: Many Asian VCDs achieve "two" soundtracks by putting one language on the left channel and another on the right. They will be mixed together into babel on a stereo system unless you adjust the balance to get only one channel.

[2.4.6] Is Photo CD compatible with DVD?

Not yet. Since Photo CDs are usually on CD-R media, they may suffer from the CD-R problem (see 2.4.3). That aside, DVD players could support Photo CD with a few extra chips and a license from Kodak. No one has announced such a player. Most DVD-ROM drives will read Photo CDs (if they read CD-Rs) since it's trivial to support the XA and Orange Book multisession standards. The more important question is, "Does the OS or application support Photo CD?" but that's beyond the scope of this FAQ.

[2.4.7] Is CD-i compatible with DVD?

In general, no. Most DVD players will not play CD-i (Green Book) discs. However, Philips has announced that it will make a DVD player that supports CD-i. Some people expect Philips to create a "DVD-i" format in attempt to breathe a little more life into CD-i (and recover a bit more of the billion or so dollars they've invested in it).

[2.4.8] Is Enhanced CD compatible with DVD?

Yes. DVD players will play music from Enhanced Music CDs (Blue Book, CD Plus, CD Extra), and DVD-ROM drives will play music and read data from Enhanced CDs. Older ECD formats such as mixed mode and track zero (pregap, hidden track) should also be compatible, but there may be a problem with DVD-ROM drivers skipping track zero (as has been the case with some new CD-ROM drivers).

[2.4.9] Is CD+G compatible with DVD?

Only the Pioneer DVL-9 player and Pioneer karaoke DVD models DV-K800 and DVK-1000 are known to support CD+G. Most other DVD-V players probably won't support this mostly obsolete format. All DVD-ROM drives support CD+G, but special software is required to make use of it.

[2.4.10] Is CDV compatible with DVD?

Sort of. CDV, sometimes called Video Single, is actually a weird combination of CD and laserdisc. Part contains 20 minutes of digital audio playable on any CD or DVD player. The other part contains 5 minutes of analog video (and digital audio) in laserdisc format, playable only on a CDV-compatible system. However, Pioneer and others have announced combination players that will play DVDs, laserdiscs, and CDVs.

[2.4.11] Is MP3 compatible with DVD?

No. MP3 is MPEG-1 Layer 3 audio compression. (MP3 is not MPEG-3.) The DVD-Video spec allows Layer 2 only. MP3 can be played on a computer with a DVD-ROM drive, but not in a DVD-Video player.

[2.5] Is laserdisc compatible with DVD?

No. Standard DVD players will not play laserdiscs, and you can't play a DVD disc on any standard laserdisc player. (Laserdisc uses analog video, DVD uses digital video; they are very different formats.)

However, Pioneer and Samsung have announced combo players that will play laserdiscs and DVDs (and also CDVs and audio CDs). Denon is rumored to have an LD/DVD player in the works also.

[2.6] Will DVD replace laserdisc? Should I buy laserdisc now or wait for DVD and HDTV?

DVD will probably replace laserdisc, but not for a very long time. Laserdisc is well established as a videophile format. There are over 9,000 laserdisc titles in the US and a total of over 35,000 worldwide that can be played on over 7 million laserdisc players. It will take DVD many years to reach this point. Until then laserdisc has the superiority of tenure. Pioneer and other laserdisc companies have committed to supporting it for years to come. There's no reason to stop buying laserdiscs, especially rare titles that may not appear on DVD for a long while if ever. Even laserdisc owners who buy DVD will not immediately replace their collection. Laserdisc and DVD will co-exist for a long while.

In December of 1996 the FCC approved the U.S. DTV standard. HDTVs will be available in late 1998 or early 1999 but they will be very expensive and won't become widespread for many years. DVD will look better on HDTVs but it won't provide high resolutions. See 2.9 for more information on DVD and HDTV.

The final answer to this question depends on you. If you need to be the first on your block with the latest gadget, you may want to get a DVD player or a combination LD/DVD player now. If you prefer to wait until DVD prices drop and bugs get worked out, you may have a lengthy wait. If you think DVD isn't a big enough improvement and decide to hold out for HTDV, you'll be in for an even longer wait. In the meantime you could be enjoying the large selection of laserdisc titles. Or you could start saving now for DVD (which won't be too expensive) or HDTV (which will be). If you buy a laserdisc player, a surround sound system, and speakers, they will be still be useful even after DVD and HDTV come out. HDTV will require a new TV set, but it will be compatible with the rest of your gear.

Unfortunately, laserdisc was hurt by anticipation of DVD before it even came out. In 1996 laserdisc player sales were down 37% even though sales of VCRs and hi-fi/surround systems were up. The silver lining in this cloud is that disc prices came down. (Laserdisc movie sales were only down 2.5% in 1996.)

[2.7] How does DVD compare to laserdisc?

  • Features: DVD has the same basic features as CLV LD (scan, pause, search) and CAV LD (freeze, slow) and adds branching, multiple camera angles, parental control, video menus, interactivity, etc., although some of these features are not available on all discs. Unlike CAV LD, DVD can't play backwards (it's technically possible, but no current players can do it).
  • Capacity: Single-layer DVD holds over 2 hours, dual-layer holds over 4 hours. CLV LD holds one hour per side, CAV holds half an hour. DVD can also hold hundreds of still pictures accompanied by over 20 hours of audio and text.
  • Convenience: An entire movie fits on one side of a DVD, so there's no need to flip the disc or wait for the player to do it. DVDs are smaller and easier to handle. DVD players can be portable, similar to CD players. Discs can be easily and cheaply sent through the mail. On the other hand, laserdiscs have larger covers for better art and text.
  • Noise: Most LD players make a whirring noise that can be heard during quiet segments of a movie. Some DVD players are as quiet as CD players, others are noisier.
  • Audio: LD has better quality on Dolby Surround soundtracks. DVD has better quality on Dolby Digital or music only. LD has 2 audio tracks: analog and digital. DVD has up to 8 audio tracks. LD uses PCM audio sampled with 16 bits at 44 kHz. DVD LPCM audio can use 16, 20, or 24 bit samples at 48 or 96 kHz (although PCM won't be used with most movies). LD has surround audio in Dolby Surround, Dolby Digital (AC-3), and DTS formats. 5.1-channel surround sound is available by using one channel of the analog track for AC-3 or both channels of the digital track for DTS. DVD uses the same Dolby Digital surround sound, usually at the same data rate (384 kbps) but can go up to 448 kbps for better quality, and can optionally include DTS (at data rates up to 1536 kbps compared to LD's 1411 kbps, but in practice DTS data rates will probably be lower on DVD than on LD). DVD players convert Dolby Digital to Dolby Surround. This conversion (downmix) process can reduce dynamic range. Combined with the effects of compression, this usually results in lower-quality sound than from LD Dolby Surround tracks.
  • Video: DVD usually has better video. LD suffers from degradation inherent in analog storage and in the composite NTSC or PAL video signal. DVD uses digital video, and even though it's heavily compressed, most professionals agree that when properly and carefully encoded it's virtually indistinguishable from studio masters. Nevertheless, this doesn't mean that the video quality of DVD, especially at first, WILL be better than LD. Only that it CAN be better. Also keep in mind that the average television is of insufficient quality to show much difference between LD and DVD. Home theater systems or HDTVs are needed to take full advantage of the improved quality. The arguments about DVD quality vs. LD quality will rage for a long time. The only final answer is to compare them side by side and form your own opinion.
  • Resolution: In numerical terms DVD has 345,600 pixels (720x480), which is 1.3 times LD's approximately 272,160 pixels (567x480). Widescreen DVD has 1.7 times the pixels of letterboxed LD (or 1.3 times anamorphic LD). As for lines of horizontal resolution, DVD ~= 500, LD ~= 425, and VHS ~= 240. (All figures are for NTSC, not PAL.)
  • Support: There are many more laserdisc players and discs. But there are already more announced DVD players than there are LD players. Many new computers will also be able to play DVD-Videos.
  • Price: DVD players are not yet cheaper than the cheapest LD player, but the success of DVD-ROM will inevitably drive the price to level of CD players. Most movies on DVD cost less than on LD, except when priced for rental.
  • Restrictions: For those outside the US, regional coding (see 1.10) is a definite drawback of DVD. For some people Macrovision copy protection (see 1.11) is an annoyance. Laserdisc has no copy protection and does not have regional differences other than PAL vs. NTSC.

Again, it will take years for DVD to reach the number of titles, installed base, and even quality of production that laserdisc has. DVD and laserdisc will coexist for at least another decade. But the potential of DVD can't be ignored -- it's the most likely long-term successor to laserdisc.

For more laserdisc info, see the Laserdisc FAQ at <>.

[2.8] Can I modify or upgrade my laserdisc player to play DVD?

It's not likely. DVD circuitry is completely different, the pickup laser is a different wavelength, the tracking control is more precise, etc. No hardware upgrades have been announced, and in any case they would probably be more expensive than buying a DVD player to put next to the laserdisc player.

[2.9] Does DVD support HDTV (DTV)? Will HDTV make DVD obsolete?

Short answers: Partially. No.

DVD-Video does not directly support HDTV. No HDTV standards were finalized when DVD was developed. In order to be compatible with existing televisions, DVD's MPEG-2 video resolutions and frame rates are closely tied to NTSC and PAL/SECAM video formats. DVD does use the same 16:9 aspect ratio and Dolby Digital audio format of HDTV.

HDTV in the US is part of the new DTV format, which includes both high definition (HD) and standard definition (SD). The resolution and frame rates of DTV in the US will generally correspond to the ATSC recommendations for SD (704x480 at 24P, 30P, 60I, 60P) and HD (1280x720 at 60P and 1920x1080 at 30P). (24P means 24 progressive frames/sec, 60I means 60 interlaced frames/sec.) The current DVD-Video spec covers all of SD except 60P. It's expected that future DVD players will output digital video signals from existing discs in SDTV formats. The HD formats are 2.7 and 6 times the resolution of DVD, and the 60P version is twice the frame rate. The ITU-R is working on BT.709 HDTV standards of 1125/60 (1920x1035/30) (same as SMPTE 240M, similar to Japan's analog MUSE HDTV) and 1250/50 (1920x1152/25) which may be used in Europe. The latter is 5.3 times the resolution of DVD's 720x576/25 format. In other words, DVD-Video does not currently support HDTV video content.

HDTV will not make DVD obsolete. Those who postpone purchasing a DVD player because of HDTV are in for a long wait. HDTV sets will become available in late 1998 or early 1999 at very high prices (about $8000 and up). It will take many years before even a small percentage of homes have HDTV sets. CEMA expects 10 percent of U.S. households to have HDTV in 2003, 20 percent by 2005, and 30 percent by 2006.

HTDV sets will include analog video connectors (composite, s-video, and component) that will work with all DVD players and other existing video equipment such as VCRs. Existing DVD players and discs will work perfectly with HDTV sets, and will provide a much better picture than any other prerecorded consumer video format, especially once new progressive-scan players become available. Since the cheapest route to HDTV reception will be HDTV converters for existing TV sets, HDTV for many viewers will look no better than DVD.

At some point, HDTV displays will support component digital video connections (YCrCb) or digital data connections (FireWire/IEEE 1394). The digital connections will provide the best possible reproduction of DVD-Video, especially in widescreen mode. Once DVD players have digital outputs, they may be usable as "transports" which output any kind of A/V data (even formats developed after the player was built) to any sort of external display or converter.

Eventually the DVD-Video format will be upgraded to a "DVD-HD" format, probably around 2003 at the earliest, based on higher-capacity discs and blue or purple lasers (already demonstrated by many DVD manufacturers). New DVD-HD players will play current DVD discs and will make them look even better, but new DVD-HD discs won't be playable in older DVD players. Ironically, DVD-ROM computers will support HDTV before DVD-Video players, since 2x drives coupled with appropriate playback and display hardware meet the 19 Mbps data rate needed for HDTV.

Note: The term "HDVD" has already been taken for "High-density Volumetric Display."

Some have speculated that a "double-headed" player reading both sides of the disc at the same time could double the data rate for applications such as HDTV. This is currently impossible since the track spirals go in opposite directions (unless all four layers are used). The DVD spec would have to be changed to allow reverse spirals on layer 0. Even then, keeping both sides in sync, especially with MPEG-2's variable bit rate, would require independently tracking heads, precise track and pit spacing, and a larger, more sophisticated track buffer.

[2.10] What's Divx?

Depending on whom you ask, Divx (formerly ZoomTV) is either an insidious evil scheme for greedy studios to control what you see in your own living room or an innovative approach to video rental that lets you get discs almost anywhere and keep them for later viewings. Regardless, Divx will confuse consumers and delay the acceptance of DVD. Developed by Circuit City and a Hollywood law firm, Divx was announced for Summer 1998 release, which means players and discs probably won't be available until Fall of 1998. Disney (Buena Vista), Twentieth Century Fox, Paramount, Universal, MGM, and Dream Works SKG will release Divx discs. JVC, Matsushita (Panasonic), Pioneer, Thomson (RCA/Proscan/GE), and Zenith are developing Divx players. Reportedly the studios supporting Divx were offered incentives totalling over $20 million.

Divx is essentially a pay-per-view variation of DVD. Divx discs will be sold for about $4 to $7. Once inserted into a Divx player the disc will play normally for the next 48 hours, after which the "owner" must pay about $3 to $5 to unlock it for another 48 hours. A Divx DVD player, which will cost $100 to $200 more than a regular player, must be hooked up to a phone line so it can call an 800 number for about 20 seconds during the night a few times each month to upload billing information. Special Divx Silver discs can be permanently unlocked by paying a higher fee, and unlimited-playback Divx Gold discs may also be offered for sale at a price similar to regular "open" DVDs. Divx players also play regular DVD discs, but Divx discs do not play in standard DVD players. Divx discs are serialized (with a barcode in the standard Burst Cutting Area) and in addition to normal DVD copy protection (see 1.11) they employ watermarking and triple DES encryption (three 56-bit keys). No computer support of Divx has been announced, and in any case special decryption hardware would be required since DES is too complex for realtime software decoding. Because of the DES encryption, Divx technology may not be allowed outside the U.S.

Advantages of Divx:

  • Viewing can be delayed, unlike rentals.
  • Discs need not be returned. No late fees.
  • You can watch the movie again for a small fee. Initial cost of "owning" a disc is reduced.
  • Discs can be unlocked for unlimited viewing (Divx Silver).
  • The disc is new; no damage from previous renters.
  • The "rental" market is opened up to other retailers, including mail order.
  • Studios get more control over the use of their content.

Disadvantages of Divx:

  • Higher player cost (about $100 to $200 more, may eventually drop to $50 more).
  • Although discs need not be returned, the viewer still must go to the effort of purchasing the disc. Cable/satellite pay per view is more convenient.
  • Higher cost than for regular DVD rental ($4 to $7 vs. $2 to $3). There are few obstacles to the company raising prices later, since it has a monopoly.
  • Casual quick viewing (looking for a name in the credits, playing a favorite scene, watching supplements) will require paying a fee.
  • All Divx titles will be pan & scan (see 3.5) and have no extras such as foreign language tracks, subtitles, biographies, trailers, and commentaries. (Divx is encouraging studios to release supplemented discs on regular DVD.)
  • The player must be hooked to your phone line, possibly requiring a new jack in your living room or a wire strung across it.
  • If your phone line is down for a period of time, you may not be able to watch Divx discs.
  • Divx is collecting information about your viewing habits. (According to Divx, the law does not allow them to use the information for resale and marketing.)
  • Divx players include a "mailbox" for companies to send you unsolicited offers.
  • Those who don't lock out their Divx player may receive unexpected bills when their kids or visitors play Divx discs.
  • Divx discs won't play in regular DVD players or on PCs with DVD-ROM drives. Uninformed consumers may buy Divx discs only to find they won't play in their non-Divx player.
  • Unlocked Silver discs will only work in players on the same account. Playback in a friend's Divx player will incur a charge. (Gold discs will play without charge in all players.)
  • Divx can't be used in mobile environments, such as a van or RV.
  • No market for used discs.
  • Divx could undermine the DVD rental business and sellthrough business (possibly resulting in higher costs for non-Divx discs).
  • If Divx goes out of business, Divx discs will be unplayable.
  • Divx players may never be available outside the U.S.

For more information, see the Divx FAQ at <> and the Anti Divx page at <>.

[3] DVD technical details

[3.1] What are the outputs of a DVD player?

Most DVD players have the following output connections:
- Composite video (CVBS) RCA/Cinch (NTSC or PAL)
- Y/C (s-video) (NTSC or PAL)
- Dual RCA stereo analog audio (with Dolby Surround encoding)
- Digital audio (IEC-958 Type II RCA coax (S/P DIF) or EIAJ CP-340 optical (Toslink)). Raw digital audio (AC-3, MPEG-2, PCM, or optional DTS or SDDS) requires an external decoder or an amplifier/receiver with built-in decoder. (Note: The digital AC-3 audio output is not the same as the RF AC-3 output on laserdisc players.)

Some players may have additional connections:
- Component analog video, NTSC or PAL (YUV: 3 RCA connectors, RGB: SCART connector or 3 RCA)
- RF video output for connecting via channel 3 or 4 to TV without direct input. (Panasonic DVD-A300, RCA 5500P)
- 6 RCA jacks for analog surround sound output. (Panasonic DVD-A300, RCA 5500P, Samsung DVD905)
- AC-3 RF output on combo LD/DVD players. LD AC-3 on RF output only, DVD AC-3 on coax/optical outputs only. (Pioneer DVL-90, DVL-700)

Most of the DVD players with component outputs use YUV, which is incompatible with RGB. European players with SCART connectors have RGB outputs. YUV to RGB transcoders are rumored to be available for $200-$300, but seem hard to track down. A $700 converter is available from avscience.

Note: The correct term for analog color-difference output is Y'Pb'Pr', not Y'Cb'Cr' (which is digital, not analog). To simplify things, this FAQ uses the term YUV in its generic sense to refer to color difference signals.

No DVD players have yet been announced with digital video outputs, but it's expected that at some point digital output will be available using FireWire (IEEE 1394) connectors (see <>).

[3.2] How do I hook up a DVD player?

It depends on your audio/video system and your DVD player. Most DVD players have 2 or 3 video hookup options and 3 audio hookup options. Choose the option with the best quality (indicated below) that is supported by your video and audio systems.


  • Component video (best): Some U.S. and Japanese players have component YUV video output in the form of 3 RCA or BNC connectors. Connectors may be labelled YUV, color difference, YPbPr, or Y/B-Y/R-Y, and may be colored green/blue/red. Some players have RGB component video output via a 20-pin SCART connector or 3 RCA or BNC connectors labelled R/G/B. Hook cables from the three video outputs of the player to the three video inputs of the display, or a SCART cable from the player to the display. Note: For equipment with RGB inputs, the YUV signal won't work; a transcoder is required. Converters from s-video are also an option; contact Markertek Video Supply, 800-522-2025. (Note: There is an unsubstantiated rumor that the Toshiba SD-3006 component outputs have poor color conversion.)
  • S-video (good): Almost all players have s-video output. Hook an s-video cable from the player to the display (or to an A/V receiver that can switch s-video). The round, 4-pin connectors may be labelled Y/C, s-video, or S-VHS.
  • Composite video (ok): All DVD players have standard RCA (Cinch) baseband video connectors. Hook a standard video cable from the player to the display (or to an A/V receiver ). The connectors are usually yellow and may be labelled video, CVBS, composite, or baseband.
  • RF video (worst): A few players have RF video output for televisions with only an antenna connection. Connect a coax cable from the player to the TV. A 300 ohm to 75 ohm adapter may be needed. Tune the TV to channel 3 or 4 and set the switch on the back of the player to match. Audio is supplied with the RF signal, but it's only mono, even on stereo TVs. If you have a player without RF output, you can buy an RF modulator (~$30) to hook up to an old TV with RF input only. You can also route the video through a VCR, but this will usually cause picture problems with any disc that's Macrovision protected (see 1.11).

Warning: If you connect your DVD player to a VCR and then to your TV, you may have problems with discs that enable the player's Macrovision circuit. This usually shows up as a repeated darkening and lightening of the picture.

Note: Most DVD players support widescreen signalling, which tells a widescreen display what the aspect ratio is so that it can automatically adjust. One standard (ITU-R BT.1119, used mostly in Europe) includes information in a video scanline. Another standard, for Y/C connectors, adds a 5V DC signal to the chroma line to designate a widescreen signal. Unfortunately, some switchers and amps throw away the DC component instead of passing it on to the TV.


Note: All DVD players have either a built-in Dolby Digital (AC-3) or MPEG audio decoder, or both. The decoder translates multi-channel audio into PCM audio. This is fed to the digital output and also converted to analog for standard audio output.

  • Digital audio (best): Almost all DVD players have digital audio outputs for Dolby Digital (AC-3), MPEG-2 audio, and PCM audio (including PCM from CDs). For DD or MPEG-2, the appropriate decoder is required in the receiver or as a separate audio processor. For PCM, a digital receiver or an outboard DAC is required. DTS is not yet available on DVDs; it will require new players and the appropriate decoder in the player or the receiver, or a separate audio processor. Some DVD players have coax connectors (SP/DIF), some have fiber-optic connectors (Toslink), and many have both. There are endless arguments over which of these is better. Coax seems to have more advocates, but suffice it to say that since the signal is digital, a quality cable of either type will provide similar results. Hook a 75-ohm coax cable or a fiber-optic cable between the player and the receiver/processor. Some players provide separate connectors for DD/MPEG and PCM. On others, you may need to select the desired output format with the player setup menu or a switch on the back of the player. Note: Make sure you use an audio quality cable; a cheap RCA patch cable may cause the audio to not work. Note: connecting to the AC-3/RF input will not work unless your reciever/decoder can autoswitch, since DVD digital audio is not in RF format (see below).
  • Component analog audio (good): Some players provide 6-channel analog output from the internal Dolby Digital decoder. The digital-to-analog conversion quality may be better or worse than an external decoder. A receiver/amplifier with 6 inputs (or more than one amplifier) is required; this type of unit is often called "Dolby Digital ready" or "AC-3 ready." Unfortunately, in most cases you will be unable to adjust the volume of individual channels. Hook 6 audio cables to the RCA connectors on the player and to the matching connectors on the receiver/amplifier. Some receivers require an adapter cable with a DB-25 connector on one end and RCA connectors on the other.
  • Stereo/surround analog audio (ok): All DVD players include two RCA connectors for stereo output. Any disc with Dolby Digital or MPEG-2 audio will automatically be decoded and downmixed to Dolby Surround output for connection to a regular stereo system or a Dolby Surround/Pro Logic system. Connect two audio cables between the player and a receiver, amplifier, or TV. Connectors may be labelled audio or left/right; left is usually white, right is usually red.
  • RF digital audio (LD only): Combination LD/DVD players include AC-3 RF output for digital audio from laserdiscs. Hook a coax cable to the AC-3 RF input of the receiver/processor. Note: digital audio from DVDs does not come out of the RF output, it comes out of the optical/coax outputs. Analog audio from LDs will come out the stereo connectors, so three separate audio hookups are required to cover all variations.

[3.3] What are the sizes and capacities of DVD?

There are many variations on the DVD theme. There are two physical sizes: 12 cm (4.7 inches) and 8 cm (3.1 inches), both 1.2 mm thick. These are the same form factors as CD. A DVD disc can be single-sided or double-sided. Each side can have one or two layers of data. The amount of video a disc can hold depends on how much audio accompanies it and how heavily the video and audio are compressed. The oft-quoted figure of 133 minutes is apocryphal: a DVD with only one audio track easily holds over 160 minutes, and a single layer can actually hold up to 9 hours of video and audio if it's compressed to VHS quality.

At a rough average rate of 4.7 Mbps (3.5 Mbps for video, 1.2 Mbps for three 5.1-channel soundtracks), a single-layer DVD holds around 135 minutes. A two-hour movie with three soundtracks can average 5.2 Mbps. A dual-layer disc can hold a two-hour movie at an average of 9.5 Mbps (very close to the 10.08 Mbps limit).

Capacities of DVD:

For reference, a CD-ROM holds about 650 MB (megabytes), which is 0.64 GB (gigabytes) or 0.68 G bytes (billion bytes). In the list below, SS/DS means single-/double-sided, SL/DL means single-/dual-layer, GB means gigabytes (2^30), G means billions of bytes (10^9).

  • DVD-5 (12cm, SS/SL): 4.38 GB (4.7 G) of data, over 2 hours of video
  • DVD-9 (12cm, SS/DL): 7.95 GB (8.5 G), about 4 hours
  • DVD-10 (12cm, DS/SL): 8.75 GB (9.4 G), about 4.5 hours
  • DVD-18 (12cm, DS/DL): 15.90 GB (17 G), over 8 hours
  • DVD-1? (8cm, SS/SL): 1.36 (1.4 G), about half an hour
  • DVD-2? (8cm, SS/DL): 2.48 GB (2.7 G), about 1.3 hours
  • DVD-3? (8cm, DS/SL): 2.72 GB (2.9 G), about 1.4 hours
  • DVD-4? (8cm, DS/DL): 4.95 GB (5.3 G), about 2.5 hours
  • DVD-R (12cm, SS/SL): 3.68 GB (3.95 G)
  • DVD-R (12cm, DS/SL): 7.38 GB (7.9 G)
  • DVD-R (8cm, SS/SL): 1.15 GB (1.23 G)
  • DVD-R (8cm, DS/SL): 2.29 GB (2.46 G)
  • DVD-RAM (12cm, SS/SL): 2.40 GB (2.58 G)
  • DVD-RAM (12cm, DS/SL): 4.80 GB (5.16 G)

Tip: It takes about two gigabytes to store one hour of average video.

The increase in capacity from CD-ROM is due to: 1) smaller pit length (~2.08x), 2) tighter tracks (~2.16x), 3) slightly larger data area (~1.02x), 4) more efficient channel bit modulation (~1.06x), 5) more efficient error correction (~1.32x), 6) less sector overhead (~1.06x). Total increase for a single layer is about 7 times a standard CD-ROM. There's a slightly different explanation at <>.

The capacity of a dual-layer disc is slightly less than double that of a single-layer disc. The laser has to read "through" the outer layer to the inner layer (a distance of 20 to 70 microns). To reduce inter-layer crosstalk, the minimum pit length of both layers is increased from .4 um to .44 um. In addition, the reference scanning velocity is slightly faster -- 3.84 m/s, as opposed to 3.49 m/s for single layer discs. Bigger pits, spaced farther apart, are easier to read correctly and are less susceptible to jitter. Bigger pits and fewer of them mean reduced capacity per layer.

See 4.2 for details of recordable DVD (DVD-R and DVD-RAM).

[3.4] What are the video details?

DVD-Video is an application of DVD-ROM. DVD-Video is also an application of MPEG-2. This means the DVD format defines subsets of these standards to be applied in practice as DVD-Video. DVD-ROM can contain any desired digital information, but DVD-Video is limited to certain data types designed for television reproduction.

A disc has one track (stream) of MPEG-2 constant bit rate (CBR) or variable bit rate (VBR) compressed digital video. A restricted version of MPEG-2 Main Profile at Main Level (MP@ML) is used. SP@ML is also supported. MPEG-1 CBR and VBR video is also allowed. 525/60 (NTSC, 29.97 interlaced frames/sec) and 625/50 (PAL, 25 interlaced frames/sec) video display systems are expressly supported. Coded frame rates of 24 fps progressive from film, 25 fps interlaced from PAL video, and 29.97 fps interlaced from NTSC video are typical. MPEG-2 progressive_sequence is not allowed, but interlaced sequences can contain progressive pictures and progressive macroblocks. In the case of 24 fps source, the encoder embeds MPEG-2 repeat_first_field flags into the video stream to make the decoder either perform 3-2 pulldown for 60 (59.94) Hz displays or 2-2 pulldown (with 4% speedup) for 50 Hz displays. In other words, the player doesn't really "know" what the encoded rate is, it simply follows the MPEG-2 encoder's instructions to produce the predetermined display rate of 25 fps or 29.97 fps. (No current players convert from PAL to NTSC or NTSC to PAL. See 1.19.) It's interesting to note that even interlaced source video is usually encoded as progressive-structured MPEG pictures, with interlaced field-encoded macroblocks used only when needed for motion. On a computer, which is not tied to the display refresh rate, the repeat_first_field flags can be mostly ignored and the video can be shown as progressive frames at the original rate. Computers can also improve the quality of interlaced source by doubling fields and displaying them as progressive frames at twice the normal rate. Most film source is encoded progressive; most video sources are encoded interlaced. These may be mixed on the same disc, such as an interlaced logo followed by a progressive movie.
See the MPEG page <> for more information on MPEG-2 video.

Picture dimensions are max 720x480 (29.97 frames/sec) or 720x576 (25 frames/sec). Pictures are subsampled from 4:2:2 ITU-R 601 down to 4:2:0, allocating an average of 12 bits/pixel. (Color depth is still 24 bits, since color samples are shared across 4 pixels.) The uncompressed source is 124.416 Mbps for video source (720x480x12x30 or 720x576x12x25), or either 99.533 or 119.439 Mbps for film source (720x480x12x24 or 720x576x12x24). Using the traditional (and rather subjective) television measurement of "lines of horizontal resolution" DVD can have 540 lines on a standard TV (720/(4/3)) and 405 on a widescreen TV (720/(16/9)). In practice, most DVD players provide about 500 lines because of filtering. VHS has about 230 (172 w/s) lines and laserdisc has about 425 (318 w/s).

Different players use different numbers of bits for the video digital-to-analog converter. (Sony and Toshiba use 10 bits, Pioneer and Panasonic use 9 bits.) This has nothing to do with the MPEG decoding process, since each original component signal is limited to 8 bits per sample. More bits in the player provide more "headroom" and more signal levels during digital-to-analog conversion, which can help produce a better picture.

Maximum video bitrate is 9.8 Mbps. The "average" bitrate is 3.5 but depends entirely on the length, quality, amount of audio, etc. This is a 36:1 reduction from uncompressed 124 Mbps (or a 28:1 reduction from 100 Mbps film source). Raw channel data is read off the disc at a constant 26.16 Mbps. After 8/16 demodulation it's down to 13.08 Mbps. After error correction the user data stream goes into the track buffer at a constant 11.08 Mbps. The track buffer feeds system stream data out at a variable rate of up to 10.08 Mbps. After system overhead, the maximum rate of combined elementary streams (audio + video + subpicture) is 10.08. MPEG-1 video rate is limited to 1.856 Mbps with a typical rate of 1.15 Mbps.

Still frames (encoded as MPEG-2 I-frames) are supported and can be displayed for a specific amount of time or indefinitely. These are generally used for menus. Still frames can be accompanied by audio.

A disc also can have up to 32 subpicture streams that overlay the video for subtitles, captions for the hard of hearing, captions for children, karaoke, menus, simple animation, etc. These are full-screen, run-length-encoded bitmaps limited to four pixel types. For each group of subpictures, four colors are selected from a palette of 16 (from the YCrCb gamut), and four contrast values are selected out of 16 levels from transparent to opaque. Subpicture display command sequences can be used to create effects such as scroll, move, color/highlight, and fade. The maximum subpicture data rate is 3.36 Mbps, with a maximum size per frame of 53220 bytes.

[3.5] How do the aspect ratios work?

Video can be stored on a DVD in 4:3 format (standard TV shape) or 16:9 (widescreen). The 16:9 format is "anamorphic," meaning the picture is squeezed horizontally to fit a 4:3 rectangle then unsqueezed during playback. DVD players can output video in four different ways:

  • full frame (4:3 video for 4:3 display)
  • letterbox (16:9 video for 4:3 display)
  • pan & scan (16:9 video for 4:3 display)
  • widescreen (16:9 video for 16:9 display)

Letterbox means the video is shown in its theatrical aspect ratio, usually 1.85:1 or 2.40:1. Since this is wider than standard 4:3 TV, black bars must be added to the top and bottom. Pan & scan means the smaller TV "window" is panned and zoomed around the wider movie picture, chopping off the sides. However, most movies are shot soft matte, which means the full TV-sized film frame is used, with the top and bottom masked off in the theater. When transferred to video, the extra picture on the film can be included during the pan & scan process. For more details and nice visual aids see Leopold's "How Film Is Transferred to Video" page, <>. A list of movie aspect ratios is at <>.

Video stored in 4:3 format is not changed by the player. It will appear normally on a standard 4:3 display. Widescreen systems will either enlarge it or add black bars to the sides. 4:3 video may have been formatted in various ways before being transferred to DVD. For example, it may have been letterboxed to hold video with a wider shape. Or it may have been panned & scanned from film composed for a wider theatrical presentation. All formatting done to the video prior to it being stored on the disc is transparent to the player. It merely reproduces the signal in standard form.

Anamorphic (16:9) video can be displayed on widescreen equipment, which stretches the video back out to its original width. If anamorphic video is shown on a standard 4:3 display, people will look like they have been on a crash diet. Widescreen mode is complicated because most movies today are shot with a "soft matte." (The cinematographer has two sets of frame marks in her viewfinder, one for 1.33 (4:3) and one for 1.85, so she can allow for both formats). A few movies are even wider, such as the 2.35 ratio of Panavision. Since most movies are wider than 1.78 (16:9), one of at least 4 methods must be used during transfer to make it fit the 1.78 rectangle: 1) add additional thin black bars to the top and bottom; 2) include a small amount of extra picture at the top and bottom from the soft matte area; 3) crop the sides; 4) pan & scan with a 1.78 window. With the first two methods, the difference between 1.85 and 1.78 is so small that the letterbox bars or extra picture are hidden in the overscan area of most televisions. Nevertheless, and especially with 2.35 movies, many DVD producers put 16:9 source on one side (or layer) of the disc and 4:3 source on the other. This way the full-frame version of the film can be used for a horizontal and vertical pan & scan & zoom process with no letterbox bars and no reduction in resolution.

See <> for a list of anamorphic DVD titles.

Anamorphic video can also be converted by the player for display on standard 4:3 TVs in letterbox or pan & scan form. The conversion options available for each disc are determined by the producer of the disc. So far no discs have been released with auto letterbox option (partly because equipment for storing the picture shift information is not widely available).

For automatic letterbox mode, the player creates black bars at the top and the bottom of the picture (60 lines each for NTSC, 72 for PAL). This leaves 3/4 of the height remaining, creating a shorter but wider rectangle. In order to fit this shorter rectangle, the picture is squeezed vertically using a "letterbox filter" that combines every 4 lines into 3. This compensates for the original horizontal squeezing, resulting in the movie being shown in its full width. The vertical resolution is reduced from 480 lines to 360.

For automatic pan & scan mode, the video is unsqueezed to 16:9 and a portion of the image is shown at full height on a 4:3 screen by following a "center of interest" offset that's encoded in the video stream according to the preferences of the people who transferred the film to video. The pan & scan "window" is 75% of the full width, which reduces the horizontal pixels from 720 to 540. The pan & scan window can only travel laterally. This does not duplicate a true pan & scan process in which the window can also travel up and down and zoom in and out. Therefore, many DVD producers choose to put a separate pan & scan version on the disc in addition to the widescreen version.

Anamorphosis causes no problems with line doublers, which simply double the lines before they are stretched out by the widescreen display.

For anamorphic video, the pixels are fatter. Different pixel aspect ratios (none of them square) are used for each aspect ratio and resolution. 720-pixel and 704-pixel sizes have the same aspect ratio because the first includes overscan. Note that "conventional" values of 1.0950 and 0.9157 are for height/width (and are tweaked to match scanning rates). The table below uses less-confusing width/height values (y/x * h/w).

720x480   720x576
704x480   704x486   352x480   352x576
4:3     0.909     1.091     1.818     2.182
16:9    1.212     1.455     2.424     2.909

Playback of widescreen material can be restricted. Programs can be marked for the following display modes:
- 4:3 full frame
- 4:3 LB (for automatically setting letterbox expand mode on widescreen TV)
- 16:9 LB only (player not allowed to pan & scan on 4:3 TV)
- 16:9 PS only (player not allowed to letterbox on 4:3 TV)
- 16:9 LB or PS (viewer can select pan & scan or letterbox on 4:3 TV)

[3.6] What are the audio details?

The DVD-Audio format is not yet specified. The January 1998 WG4 draft indicates that LPCM will be mandatory, with up to 8 channels at sample rates of 48/96/192 kHz (also 44.1/88.2/176.4 kHz) and sample sizes of 16/20/24 bits. Multichannel PCM will be downmixable by the player. All other audio formats of DVD-Video (described below) will be optional. Sony and Philips are promoting a competing format based on DSD. See 1.12 for more info.

The following details are for audio tracks on DVD-Video. Some DVD manufacturers such as Pioneer are developing audio-only players using the DVD-Video format.

A disc can have up to 8 audio tracks (streams). Each track can be in one of three formats:

  • Dolby Digital (formerly AC-3): 1 to 5.1 channels
  • MPEG-2 audio: 1 to 5.1 or 7.1 channel
  • PCM: 1 to 8 channels.

Two additional optional formats are provided: DTS and SDDS. Both require external decoders and are not supported by all players.

The ".1" refers to a low-frequency effects (LFE) channel that connects to a subwoofer. This channel carries an emphasized bass audio signal.

Linear PCM is uncompressed (lossless) digital audio, the same format used on CDs and most studio masters. It can be sampled at 48 or 96 kHz with 16, 20, or 24 bits/sample. (Audio CD is limited to 44.1 kHz at 16 bits.) There can be from 1 to 8 channels. The maximum bitrate is 6.144 Mbps, which limits sample rates and bit sizes with 5 or more channels. It's generally felt that the 96 dB dynamic range of 16 bits or even the 120 dB range of 20 bits combined with a frequency response of up to 22,000 Hz from 48 kHz sampling is adequate for high-fidelity sound reproduction. However, additional bits and higher sampling rates are useful in studio work, noise shaping, advanced digital processing, and three-dimensional sound field reproduction. DVD players are required to support all the variations of LPCM, but some of them may subsample 96 kHz down to 48 kHz, and some may not use all 20 or 24 bits. The signal provded on the digital output for external digital-to-analog converters may be limited to less than 96 kHz or less than 24 bits.

Dolby Digital is multi-channel digital audio, compressed using AC-3 coding technology from original PCM with a sample rate of 48 kHz at up to 24 bits. The bitrate is 64 kbps to 448 kbps, with 384 being the normal rate for 5.1 channels and 192 being the normal rate for stereo (with or without surround encoding). The channel combinations are (front/surround): 1/0, 1+1/0 (dual mono), 2/0, 3/0, 2/1, 3/1, 2/2, and 3/2. The LFE channel is optional with all 8 combinations. For details see ATSC document A/52 <>. Dolby Digital is the format used for audio tracks on almost all DVDs.

MPEG audio is multi-channel digital audio, compressed from original PCM format with sample rate of 48 kHz at 16 bits. Both MPEG-1 and MPEG-2 formats are supported. The variable bitrate is 32 kbps to 912 kbps, with 384 being the normal average rate. MPEG-1 is limited to 384 kbps. Channel combinations are (front/surround): 1/0, 2/0, 2/1, 2/2, 3/0, 3/1, 3/2, and 5/2. The LFE channel is optional with all combinations. The 7.1 channel format adds left-center and right-center channels, but will probably be rare for home use. MPEG-2 surround channels are in an extension stream matrixed onto the MPEG-1 stereo channels, which makes MPEG-2 audio backwards compatible with MPEG-1 hardware (an MPEG-1 system will only see the two stereo channels.) MPEG Layer III (MP3) and MPEG-2 AAC (aka NBC, aka unmatrix) are not supported by the DVD-Video standard.

DTS (Digital Theater Sound) is an optional multi-channel (5.1) digital audio format, compressed from PCM at 48 kHz at up to 20 bits. The data rate is from 64 kbps to 1536 kbps. Channel combinations are (front/surround): 1/0, 2/0, 3/0, 2/1, 2/2, 3/2. The LFE channel is optional with all 6 combinations. The DVD standard includes an audio stream format reserved for DTS, but first-generation players ignore it. A few demo discs were created by using a "fake" PCM track containing DTS audio (this is the same technique used with CDs and laserdiscs). These are the only DTS DVD discs that work on all players. New DTS-compatible players and official DTS discs using the proper DTS audio stream will arrive in mid 1998. DTS-compatible players will carry an official "DTS Digital Out" logo. Some manufacturers may provide upgrades to make existing discs comaptible with DTS discs. According to DTS, existing DTS decoders will work with DTS DVDs. Note: All DVD players can play DTS audio CDs. For more info visit <>.

SDDS (Sony Dynamic Digital Sound) is an optional multi-channel (5.1 or 7.1) digital audio format, compressed from PCM at 48 kHz. The data rate can go up to 1280 kbps. Sony has not announced any plans to support SDDS on DVD.

THX (Tomlinson Holman Experiment) is not an audio format. It's simply an additional set of processes applied by THX-certified surround sound amplifiers. "THX 4.0" processing is added to Dolby Pro Logic: crossover sends bass from front channels to subwoofer; re-equalization on front channels; timbre matching on rear channels; decorrelation of rear channels; bass curve that emphasizes low frequencies. "THX 5.1" processing is added to Dolby Digital and improves on 4.0: rear speakers are now full range, so crossover sends bass from both front and rear to subwoofer; decorrelation is turned on automatically when rear channels have the same audio, but not during split-surround effects, which don't need to be decorrelated.

Discs containing 525/60 video (NTSC) must use PCM or Dolby Digital on at least one track. Discs containing 625/50 video (PAL/SECAM) must use PCM or MPEG audio or Dolby Digital on at least one track. Additional tracks may be in any format. A few first-generation players, such as those made by Matsushita, can't output MPEG-2 audio to external decoders.

The original spec required either MPEG audio or PCM on 625/50 discs. There was a brief scuffle led by Philips when early discs came out with only two-channel MPEG and multichannel Dolby Digital, but the DVD Forum clarified in May 1997 that only stereo MPEG audio was mandatory for 625/50 discs. In December 1997 the lack of MPEG-2 encoders (and decoders) was a big enough problem that the spec was revised to allow Dolby Digital as the only audio track on 625/50 discs.

For stereo output (analog or digital), all players have a built-in 2-channel Dolby Digital decoder that downmixes from 5.1 channels (if present on the disc) to Dolby Surround stereo (i.e., 5 channels are matrixed into 2 channels to be decoded to 4 by an external Dolby Pro Logic processor). PAL players also have an MPEG or MPEG-2 decoder. Both Dolby Digital and MPEG-2 support 2-channel Dolby Surround as the source in cases where the disc producer can't or doesn't want to remix the original onto discrete channels. This means that a DVD labelled as having Dolby Digital sound may only use the L/R channels for surround or "plain" stereo. Even movies with old monophonic soundtracks may use Dolby Digital -- but only 1 or 2 channels. Sony players can optionally downmix to non-surround stereo.

The Dolby Digital downmix process does not usually include the LFE channel and may compress the dynamic range in order to improve dialog audibility and keep the sound from becoming "muddy" on average home audio systems. This can result in reduced sound quality on high-end audio systems. Some players have the option to turn off the dynamic range compression. The downmix is auditioned when the disc is prepared, and if the result is not acceptable the audio may be tweaked or a separate L/R Dolby Surround track may be added. Experience has shown that minor tweaking is sometimes required to make the dialog more audible within the limited dynamic range of a home stereo system, but that a separate track is not usually necessary. If surround audio is important to you, you will hear significantly better results from multichannel discs if you have a Dolby Digital system.

All five audio formats support karaoke mode, which has two channels for stereo (L and R) plus an optional guide melody channel (M) and two optional vocal channels (V1 and V2).

A DVD-5 with only one surround stereo audio stream (at 192 kbps) can hold over 55 hours of audio. A DVD-18 can hold over 200 hours.

Many people complain that the audio level from DVD players is too low. In truth the audio level is too high on everything else. Movie soundtracks are extremely dynamic, ranging from near silence to intense explosions. In order to support an increased dynamic range and hit peaks (near the 2V RMS limit) without distortion, the average sound volume must be lower. This is why the line level from DVD players is lower than from almost all other sources. And so far, unlike on CDs and LDs, the level is much more consistent between discs.

[3.7] How do the interactive features work?

DVD-Video players (and software DVD-Video navigators) support a command set that provides rudimentary interactivity. The main feature is menus, which are present on almost all discs to allow content selection and feature control. Each menu has a still-frame graphic and up to 36 highlightable, rectangular "buttons" (only 12 if widescreen, letterbox, and pan & scan modes are used). Remote control units have four arrow keys for selecting onscreen buttons, plus numeric keys, select key, menu key, and return key. Additional remote functions may include freeze, step, slow, fast, scan, next, previous, audio select, subtitle select, camera angle select, play mode select, search to program, search to part of title (chapter), search to time, and search to camera angle. Any of these features can be disabled by the producer of the disc.

Additional features of the command set include simple math (add, subtract, multiply, divide, modulo, random), bitwise and, bitwise or, bitwise xor, plus comparisons (equal, greater than, etc.), and register loading, moving, and swapping. There are 24 system registers for information such as language code, audio and subpicture settings, and parental level. There are 16 general registers for command use. A countdown timer is also provided. Commands can branch or jump to other commands. Commands can also control player settings, jump to different parts of the disc, and control presentation of audio, video, subpicture, camera angles, etc.

DVD-V content is broken into "titles" (movies or albums), and "parts of titles" (chapters or songs). Titles are made up of "cells" linked together by one or more "program chains" (PGC). A PGC can be defined as sequential play, random play (may repeat), or shuffle play (random order but no repeats). Individual cells may be used by more than one PGC, which is how parental management and seamless branching are accomplished: different PGCs define different sequences through mostly the same material.

Additional material for camera angles and seamless branching is interleaved together in small chunks. The player jumps from chunk to chunk, skipping over unused angles or branches, to stitch together the seamless video. Since angles are stored separately, they have no direct effect on the bitrate but they do affect the playing time. Adding 1 camera angle for a program roughly doubles the amount of space needed (and cuts the playing time in half).

[4] DVD and computers

[4.1] Can I play DVD movies on my computer?

Only if your computer has the right stuff. In addition to a DVD-ROM drive, you must have extra hardware to decode MPEG-2 video and Dolby Digital/MPEG-2/PCM audio. The computer operating system or playback system must support regional codes and be licensed to decrypt copy-protected movies. You may also need software that can read the MicroUDF format used to store DVD data files and interpret the DVD control codes. It's estimated that 10-30% of new computers with DVD-ROM drives will include decoder hardware, and that most of the remaining DVD-ROM computers will include movie playback software. Hardware upgrade kits can also be purchased separately for $500 to $1,000. (OEM price for playback hardware is about $200.) Creative and Hi-Val upgrade kits require a 133 Mhz Pentium. E4's CoolDVD upgrade kit requires a 120 MHz 604 PowerPC or better.

Note: The QuickTime MPEG Extension for MacOS is for MPEG-1 only and does NOT play MPEG-2 DVD-Video.

Some DVD-ROMs and a few DVD-Videos use video encoded using MPEG-1 instead of MPEG-2. Many existing computers have MPEG-1 hardware built in or are able to decode MPEG-1 with software.

CompCore Multimedia and Mediamatics make software to play DVD-Video movies (SoftDVD, DVD Express). Both require at least a 233 MHz Pentium MMX with AGP and an IDE/SCSI DVD-ROM drive with bus mastering DMA support to achieve about 20 frame/sec film rates (or better than 300 MHz for 30 frame/sec video), and can decrypt copy-protected movies (see 1.11). Oak's software requires hardware support. These software "navigators" support most DVD-Video features (menus, subpictures, etc.) and can emulate a DVD-Video remote control.

CompCore, Mediamatics, and Oak Technology have defined standards to allow certain MPEG decoding tasks to be performed by hardware on a video card and the remainder by software. Video graphics controllers with this feature are being called "DVD MPEG-2 accelerated." (The Mediamatics standard is called MVCCA.)

If you have at least a 433 MHz Alpha workstation you'll be able to play DVD movies at full 30 fps in software.

[4.2] What are the features and speeds of DVD-ROM drives?

Most DVD-ROM drives have a seek time of 150-200 ms, access time of 200-250 ms, and data transfer rate of 1.3 MB/s (11.08*10^6/8/2^20) with burst transfer rates of up to 12 MB/s or higher. The data transfer rate from DVD-ROM discs is roughly equivalent to a 9x CD-ROM drive. DVD spin rate is about 3 times faster than CD, so a few DVD-ROM drives read CD-ROM data at 3x speed, but most are 12x or faster. 2x DVD-ROM drives are available, and 5x drives have been announced. New 2x DVD-ROM drives (Hitachi, Creative) read CD-ROMs at 20x and 24x speeds.

Connectivity is similar to that of CD-ROM drives: EIDE (ATAPI), SCSI-2, etc. All DVD-ROM drives have audio connections for playing audio CDs. No DVD-ROM drives have been announced with DVD audio or video outputs (which would require internal audio/video decoding hardware).

DVD-ROMs use a MicroUDF/ISO 9660 bridge file system. The OSTA UDF file system will eventually replace the ISO 9660 system of CD-ROMs, but the bridge format provides backwards compatibility until operating systems support UDF.

[4.3] What about recordable DVD: DVD-R, DVD-RAM, DVD+RW, and DVD-ER?

There are two recordable versions of DVD-ROM: DVD-R (record once) and DVD-RAM (erase and record many times), with capacities of 3.95 and 2.58 billion bytes. Final versions of both specifications were published August 1997. DVD-R and DVD-RAM are not currently usable for home video recording (see 1.14).

DVD-R uses organic dye polymer technology like CD-R and is compatible with almost all DVD drives. The technology will improve to support 4.7 billion bytes by 1999 or 2000, which is crucial for desktop DVD-ROM and DVD-Video production.

DVD-RAM uses phase-change (PD) technology and is not compatible with current drives (because of defect management, reflectivity differences, and minor format differences). A wobbled groove is used to provide clocking data, with marks written in both the groove and the land between grooves. The grooves and pre-embossed sector headers are molded into the disc during manufacturing. New DVD-ROM drives that can read DVD-RAM discs are expected in early 1998. Single-sided DVD-RAM discs come with or without cartridges. There are two types of cartridges: type 1 is sealed, type 2 allows the disc to be removed. Double-sided DVD-RAM discs will be available in sealed cartridges only. Cartridge dimensions are 124.6mm x 135.5mm x 8.0mm. Future DVD-RAM discs may use a contrast enhancement layer and a thermal buffer layer to achieve higher density. Hitachi has announced reaching 4.7 billion bytes by reducing mark size from 0.41/0.43 microns to 0.28/0.30 microns and track pitch from 0.74 microns to 0.59 microns.

Pioneer released DVD-R drives in October 1997 for $17,000. This price could drop within a few years to less than $5,000. Initial price for blank DVD-Rs is $50. DVD-RAM drives will be introduced for less than $1000, with blank discs at about $30 for single-sided and $45 for double-sided. Disc prices for both DVD-R and DVD-RAM will drop quickly, but DVD-R discs will probably be cheaper in the long run. Toshiba, Pioneer, and Hitachi expect DVD-RAM to be available in early 1998, which means it will probably appear in the middle of 1998.

The primary advantages of DVD-R drives, which are used primarily for DVD production, are higher capacity and compatibility with all DVD players and drives. Matsushita, Taiyo Yuden, Mitsubishi, and Hitachi Maxell have all announced 4.7-billion-byte DVD-R formats. These are not competing DVD-R formats, merely manufacturing advances that allow higher density. The discs may not be readable in first-generation drives and players, but will be supported by all future DVD drives.

DVD Phase-Change Rewritable, called DVD+RW without the blessing of the DVD Forum, is a competing erasable format announced by Philips, Sony, Hewlett-Packard and others based on CD-RW technology. DVD+RW drives will read DVD-ROMs and CDs, but are not compatible with DVD-RAM. Minor changes to DVD-ROM drives will allow them to read DVD+RW discs. DVD+RW, which holds 2.8 gigabytes (3G) uses phase-change technology with wobbled groove and either CLV format for sequential video access (read at CAV speeds by drive) or CAV format for random access. DVD+RW will not be ready for production until late 1998 at the earliest, and its backers claim it will be used only for computer data, not home video. Second-generation DVD+RW drives will write CD-Rs and CD-RWs.

DVD-R/W is yet another announced phase-change erasable format. Developed by Pioneer based on DVD-R, DVD-R/W uses the same track pitch, mark length, and rotation control, and should be playable in first-generation DVD drives and players. DVD-R/W uses groove recording with address info on land areas for synchronization at write time (land data is unnecessary during reading). Capacity will probably be 3.95 billion bytes, later expanded to 4.7.

Other upcoming potential competitors to DVD-RAM include ASMO (formerly MO7), which holds 5 to 6 billion bytes, and NEC's MMVF (Multimedia Video Format), which holds 5.5 billion bytes. Both are expected to read DVD-ROM (and DVD-R) but not DVD-RAM or DVD+RW.

[5] DVD production

DVD production has two phases: development and replication.

DVD-ROMs can be developed with traditional multimedia software tools such as Macromedia Director, Quark mTropolis, and C++. DVD-ROMs that take advantage of DVD-Video's MPEG-2 video and multichannel Dolby Digital or MPEG-2 audio require audio/video encoding.

DVD-Video development has three basic parts: encoding, authoring (design, layout, and testing), and premastering (formatting a disc image). The entire process is sometimes referred to as authoring. Development facilities are provided by many service bureaus (see 5.3) for around $300/hour. If you intend to produce numerous DVD-Video titles (or you want to set up a service bureau), you may want to invest in authoring and encoding systems (see 5.2).

Replication (including mastering) is usually a separate job done by large plants that also replicate CDs (see 5.3). DVD replication equipment typically costs millions of dollars. Most replication plants provide "one-off" or "check disc" services, where one to ten discs are made for testing before mass duplication.

[5.1] How much does it cost to produce a DVD? Isn't it more expensive than videotape, laserdisc, and CD-ROM?

Videotape, laserdisc, and CD-ROM can't be compared to DVD in a straightforward manner. There are basically three stages of costs: production, pre-mastering (authoring, encoding, and formatting), and mastering/replication.

DVD production costs are not much higher than for existing media, unless the extra features of DVD-Video such as multiple sound tracks, camera angles, etc. are employed.

Pre-mastering costs are proportionately the most expensive part of DVD. Video and audio must be encoded, menus and control information have to be authored and encoded, it all has to be multiplexed into a single data stream, and finally encoded in low level format. Warner's charges for compression are $120/min for video, $20/min for audio, $6/min for subtitles, plus formatting and testing at about $30/min. A ballpark estimate for producing a two-hour DVD movie is about $30,000. If you want to do pre-mastering yourself, authoring and encoding systems can be purchased from $100,000 to over $2 million. These prices will drop very rapidly in the next few years to where DVDs can be produced on desktop computer systems using additional hardware costing less than $20,000.

Videotapes don't really have a mastering cost, and they run about $2.40 for replication. CDs cost about $1,000 to master and $0.50 to replicate. Laserdiscs cost about $3,000 to master and about $8 to replicate. As of Feb 1998, DVDs cost about $2000 to master and about $1.80 to replicate. Since DVD production is based mostly on the same equipment used for CD production, mastering and replication costs will quickly drop to CD levels. Pre-mastering costs are mostly for authoring systems and encoding systems which cost hundreds of thousands of dollars, but these too will get much cheaper in the next few years.

Double-sided or dual-layer discs cost only slightly more to replicate, since all that's required is stamping data on the second substrate (and using transparent glue for dual layers). Double-sided/dual-layer discs are more difficult and not yet commercially available.

[5.2] What DVD authoring systems are available and how much do they cost?

  • DVD-Fab from Optibase. DVD-Video authoring/encoding system on Windows NT. Includes MPEG Fusion MPEG-2 encoder. <>
  • DVDit from Sonic Solutions. $900 Macintosh utility for converting PowerPoint presentations into DVD-Video format. <>
  • DVDMaestro from Spruce Technologies. $75,000 authoring/encoding system on Windows NT. <>
  • DVD Creator from Sonic Solutions. $100,000 complete system for DVD-Video authoring/encoding on Macintosh. Includes DVD Producer ($25,000), DVD Studio, and DVD PrePlay (for testing) <>
  • DVD Vobulator from Sonic Solutions. $5000 DVD-ROM creation system on Macintosh. <>
  • DVMotion (aka CDMotion for DVD) from MTC. $10,000 authoring system, oriented toward multimedia DVD-ROM production. <>
  • DVD-Professional SL from Minerva. $100,000 DVD-Video authoring/encoding on Windows NT. Includes Publisher 300 and Minerva Studio. <>
  • DVD-RICH from Gunzameory. $30,000 DVD-Video authoring/encoding on Windows 95. <>
  • Scenarist II from Daikin. $35,000 DVD-Video authoring on SGI. <>
  • ZX-2000 from Zapex Technologies. MPEG-2 video encoding, MPEG/DD audio encoding.
  • InnovaCom, Panasonic, JVC, Toshiba, and Pioneer all have authoring systems under development but nothing available at the moment.

[5.3] Who can produce a DVD for me?

  • [A] All Post (CA), 818-556-5756.
  • [R] Americ Disc (CA, FL, Canada) <> 514-745-2244
  • [AS] AVM Dialog AB (Goteborg, Sweden) <>
  • [A] Cinram POP DVD Center (Santa Monica, CA)
  • [R] Cinram, Inc. (Richmond, IN)
  • [A] CKS|Pictures (CA & NY), <> 408-342-5009.
  • [A] Complete Post (CA).
  • [AS] CRUSH Digital Video (NY), <> 212-965-1501.
  • [A] D2 Productions (CA), <> 818-576-8113.
  • [A] dHouse (CA), <>.
  • [A] Digital Video Compression Corporation (CA), <> 818-777-5185.
  • [A] Digital Video Mastering (Sydney, Australia)
  • [R] Disc Manufacturing Inc. (AL & CA), <> 800-433-DISC, 302-479-2525.
  • [A] Digital Media Group (Amsterdam, The Netherlands) <> +31-20-422-6317.
  • [AS] EDS Digital Studios (CA), 213-850-1165.
  • [A] Electric Switch (London), 44-0-131-555-6055 <>
  • [A] Film- und Videotechnik B. Gurtler (Munchen, Germany)
  • [A] Hecker & Schneider GmbH (Dortmund, Germany)
  • [A] IBM InteractiveMedia (GA), <> 770-835-7193.
  • [R] Imation (formerly 3M) (WI), 612-704-4898.
  • [AS] Intel (OR), <> 503-264-3555.
  • [R] JVC Disc America (CA), 310-274-2221.
  • [AS] KAO Infosystems (CA), <> 510-657-8425.
  • [A] k-kontor[Hamburg] kommunikations (Hamburg, Germany), <> +49-40-850-9021.
  • [AR] Kao (ON), 800-871-MPEG.
  • [AR] Kao Infosystems (Fremont, CA), 800-525-6575.
  • [AR] LaserPacific (CA), <> 213-462-6266.
  • [AR] Memory-Tech Corporation (Tokyo, Japan).
  • [R] Metatec (OH), <> 614-761-2000.
  • [AS] NB Digital Solutions (MD), <>
  • [R] Nimbus Manufacturing. <> 804-985-1100.
  • [A] NOB Interactive (Netherlands) <> +31-(0)35-677-5413
  • [AS] One(UK) Ltd. (London, UK) <> +44-171-316-7800 (Daikin Authorized Expertise Center for Europe)
  • [R] Optical Disc Corporation, 310-946-3050. (LaserWave DirectCut DVD recorder for creating single copies.)
  • [R] Optical Disc Media (CA)
  • [A] Pacific Coast Sound Works (CA), 213-655-4771.
  • [R] Pacific Mirror Image (Melbourne, Australia)
  • [A] Pacific Ocean Post Sound (CA), audio only, 310-458-9192.
  • [A] Pacific Video Resources (CA), <> 415-864-5679.
  • [A] Paris Media System (Paris, France).
  • [A] Pioneer France (Nanterre, France), 33 1 47 60 79 30.
  • [R] Pioneer Video Manufacturing, Inc., <> 10-518-0710.
  • [AR] PolyGram Manufacturing & Distribution Center (Langenhagen, Germany), +49 511 972 1486.
  • [AS] Rainmaker Interactive (BC), <> 604-874-8700.
  • [AR] RiTEK Corporation (Taiwan)
  • [AR] Sonopress (NC & Germany) <>
  • [A] Sunset Post (CA), <> 818-956-7912.
  • [A] Stimulus (Calgary, Alberta)
  • [A] Sync Sound (NY), 212-246-5580 (5.1 audio).
  • [R] Technicolor, <> 800-732-4555.
  • [AS] Valkieser Solutions (Hilversum, Netherlands), <> +31-35-6714-300.
  • [ASR] Warner Advanced Media Operations, 717-383-3291.
  • [A] Zapex

[A] Authoring (including encoding and premastering).
[R] Replication (mastering and/or one-offs).
[S] Use Daikin Scenarist authoring system.

See Robert's DVD Info page <> for more pointers.

[5.4] Who can test or verify DVDs?

[6] Miscellaneous

[6.1] Who invented DVD and who owns it? Whom to contact for specifications and licensing?

DVD is the work of Toshiba, Matsushita, Philips, Sony, and others. There were originally two next-generation standards for DVD. The MMCD format was backed Sony, Philips, and others. The competing SD format was backed by Toshiba, Time Warner, and others. A group of computer companies led by IBM insisted that the DVD proponents agree on single standard. The combined DVD format was announced in September of 1995, avoiding a confusing and costly repeat of the VHS vs. BetaMax videotape battle (or the quadraphonic sound battle of the 1970s).

No single company "owns" DVD. The standard was developed by a consortium of 10 companies: Hitachi, JVC, Matsushita, Mitsubishi, Philips, Pioneer, Sony, Thomson, Time Warner, and Toshiba. Working groups with representatives from many other companies also contributed. In May 1997, the Consortium was replaced by the DVD Forum, which is open to all companies. Visit Robert's DVD Info page <> for links to Web pages of companies working with DVD.)

The official DVD specification books are available from Toshiba after signing a nondisclosure agreement and paying a $5000 fee. Contact Toshiba DVD Products 1-1 Shibaru 1-Chome, Minato-ku, Tokyo 105-01, Japan, 81-3-3457-2473, fax 81-3-5444-9401.

Any company making DVD products must license the patented technology from a Philips/Pioneer/Sony pool, a Hitachi/Matsushita/Mitsubishi/Time Warner/Toshiba/Victor pool, and from Thomson. Total royalties are about 5% for a DVD-Video player, $6 for a DVD-ROM drive and decoder, and 10 cents for a DVD disc. Matsushita licenses the CSS encryption technology free of charge. Macrovision licenses its analog anti-recording technology free of charge to hardware makers, but charges a per-copy royalty to content publishers. The DVD format and logo must also be licensed; contact Toshiba DVD Business Promotion and Support: 81-3-5444-9580, fax 81-3-5444-9430. An MPEG-2 patent license is also required, from MPEG LA (Licensing Adminstrator). Cost is $4 for a DVD player or decoder card and 4 cents for each DVD disc. Contact MPEG LA for more info: <>.

[6.2] Who is making or supporting DVD products?

The following companies have made official statements of products specifically designed for the DVD format.

Consumer electronics:

  • Akai: DVD-Video player
  • Alpine: DVD car navigation/entertainment system
  • Altec Lansing: DVD audio technology
  • Clarion: DVD-ROM car navigation system
  • Denon: DVD-Video player
  • Faroudja: DVD-Video player
  • Fisher: DVD-Video player
  • Harman Kardon: DVD-Video player
  • Hitachi: DVD-Video player
  • Hyundai: DVD-Video player
  • Innovacom: PC/TV with DVD support
  • JVC (Victor): DVD-Video players
  • Kenwood: DVD-Video player
  • LG Electronics (GoldStar): DVD-Video players
  • Matsushita (Panasonic/National/Technics/Quasar): DVD-Video players, DVD-ROM car navigation system
  • Meridian: DVD-Video player
  • Mitsubishi: DVD-Video players
  • NEC: DVD-RAM video camera
  • Onkyo: DVD-Video player
  • Philips (Magnavox/Marantz/Norelco): DVD-Video player
  • Pioneer: DVD-Video players, DVD-ROM car navigation system
  • Runco: DVD-video player and changer
  • Samsung: DVD-Video players
  • Sanyo: DVD-Video player
  • Sharp: DVD-Video player
  • Sony: DVD-Video players
  • Thomson (RCA/GE/Proscan/Ferguson/Nordmende/Telefunken/Saba/Brandt): DVD-Video players
  • Toshiba: DVD-Video players
  • Yamaha: DVD-Video player
  • Zenith: DVD-Video player

Studios, video publishers, and distributors:

  • Aftermath Media/Funsoft Holdings (interactive movie)
  • All Day Entertainment
  • Anchor Bay
  • BMG (Sonopress)
  • Cecchi Gori
  • Columbia TriStar (Sony) (37 titles in 1997)
  • Concorde Video (12 Monkeys, German)
  • Criterion (6 titles beginning in Feb 1998)
  • Delos International (mostly audio)
  • Digital Disc Entertainment
  • Digital Leisure (formerly ReadySoft) (Dragon's Lair, Space Ace)
  • Dimension
  • Disney (Buena Vista Home Video, Dimension, Hollywood, Miramax, Touchstone)
  • DreamWorks SKG
  • DVD International (distributor)
  • Elite Entertainment
  • Fox Lorber
  • Gainax (anime)
  • HBO (Warner)
  • Image Entertainment (distributor)
  • Impressive (adult)
  • Laserdisc Entertainment (adult)
  • LIVE Entertainment (Warner)
  • Lumivision
  • Master Tone
  • MCA
  • Metro Global Media (adult)
  • Metromedia
  • MGM/UA (Warner)
  • Microsoft (Encarta DVD-ROM)
  • Mill Reef (Earthlight)
  • MPI
  • New Line (Warner)
  • Orion Pictures (distributed by Image)
  • Paramount Home Video (Divx only)
  • Pioneer Entertainment (distributor)
  • Playboy
  • Polygram (Philips partner)
  • Pony Canyon (Japan)
  • Pro7 Home Enterntainment (Germany)
  • Republic Pictures (majority owned by Paramount)
  • Roadshow Entertainment (Australia)
  • Samsung Entertainment Group
  • Simitar (Beast) (200+ titles in 1997)
  • Sierra Vista Entertainment (Innovacom)
  • Silver Screen
  • Sony Music Entertainment/Sony Wonder
  • Tai Seng
  • Toshiba EMI
  • Troma
  • Turner
  • Twentieth Century Fox (Divx only, so far)
  • United American
  • Universal Studios Home Video (Matsushita) (60+ titles by June 1998)
  • VCA Labs (adult)
  • Victor Entertainment (JVC)
  • Vidmark
  • Vivid Entertainment (adult)
  • Warner Home Video (Toshiba partner) (125 titles in 1997)
  • Warner Bros. Records (Toshiba partner)

A list of studio addresses is available at <>

Computer hardware/software:

  • Alliance Semiconductor: DVD-accelerated video controller chips
  • Apple: DVD-ROM drives, DVD-ROM-equipped computers, software drivers, playback hardware and software (QuickTime)
  • AST: DVD-ROM-equipped computers (with MMX-based playback software)
  • ATI Technologies: DVD-accelerated video audio/video cards
  • Axis Communications: DVD-ROM servers
  • C-Cube: DVD encoder and decoder chips
  • CEI: DVD playback hardware and software
  • Chromatic Research: DVD decoder and playback chips
  • Cirrus Logic: DVD-accelerated video controller chips
  • Compaq: DVD-ROM-equipped computers
  • Creative Technology: DVD-accelerated audio/video cards, DVD upgrade kit
  • Diamond Multimedia: DVD playback hardware (Toshiba drive) (upgrade kit)
  • Digital: DVD software playback (for Alpha workstations), DVD encoder chips
  • DynaTek: DVD upgrade kit
  • E4 (Elecede): DVD playback hardware
  • Elektroson: DVD-recordable software (top.GEAR)
  • ESS Technology: playback chipset, player reference design
  • Fujitsu: DVD-ROM-equipped computers
  • Gatway: DVD-ROM-equipped computers
  • Harman Int.: DVD jukebox
  • Hitachi: DVD-ROM drives, decoder chips
  • Hi-Val: DVD playback hardware (upgrade kit)
  • Hyundai: DVD decoder chips
  • IBM: DVD-ROM-equipped computers, decoder chips
  • Innovacom: DVD encoder and decoder systems
  • Intel: DVD playback hardware (MMX) and software
  • JVC: DVD-ROM drives
  • Kasan: decoder hardware
  • LG Electronics: DVD-ROM drives
  • LSI: DVD decoder chips and playback cards
  • LuxSonor: DVD playback chips
  • Margi: DVD decoder card for notebook PCs
  • Matrox: DVD-accelerated video cards
  • Matsushita (Panasonic): DVD-ROM drives, upgrade kits, DVD/Web integration, DVD-RAM still-image recorder
  • Mediamatics: DVD playback software and hardware
  • Medianix: Dolby Digital decoder hardware with Spatializer 3D audio
  • Microsoft: DVD drivers and playback software (ActiveMovie)
  • Mitsubishi: DVD-ROM drives
  • Motorola: DVD decoder chips
  • Number 9: DVD-accelerated audio/video cards
  • NEC: DVD-ROM drives
  • NSM: DVD-ROM jukebox
  • Oak Technology: DVD playback hardware and software
  • Packard Bell: DVD-ROM-equipped computers
  • Philips: DVD-ROM drives, decoder chips
  • Pioneer: DVD-ROM drives
  • Procom: DVD-ROM jukebox
  • Quadrant International: DVD-Video navgation software
  • S3: DVD-accelerated video controller chips
  • Samsung: DVD-ROM drives and DVD-ROM-equipped computers
  • SGS-Thomson: DVD playback hardware (w/Microsoft)
  • SICAN: DVD decoder chips
  • Software Architects: DVD-recordable software (w/Elektroson)
  • Sony: DVD-ROM drives and DVD-ROM-equipped computers
  • STB Systems: DVD playback hardware (upgrade kit)
  • TDK: blank DVD-RAM discs
  • Toshiba: DVD-ROM drives and DVD-ROM-equipped computers
  • Trident Microsystems: DVD decoder chips, DVD-accelerated video controller chips
  • Truevision: DVD playback software (Microsoft Active Movie 2.0)
  • Verbatim Australia (ActiveMedia): DVD playback hardware (upgrade kit)
  • Wired: DVD playback hardware and software
  • Yamaha: AC-3 decoder chips
  • Zoran/CompCore: DVD software and hardware playback, DVD decoder chips

Computer software titles on DVD-ROM:

[6.3] Where can I get more information about DVD?

Here are a few of the top DVD info pages. For more extensive pointers go to Robert's page, which has all the links you will ever need.

You might also want to take a look at the book DVD Demystified, by the author of this FAQ. More info at <>.

[7] Leftovers

[7.1] Unanswered questions

(If you know the answer to any of these, please speak up!)

  • Any more RSDL switch times that aren't in the list? (1.27)
  • Any more flippers that aren't in the list? (1.21)
  • What is the exact format of component Y/R-Y/B-Y video output on DVD players? YPrPb with Rec. 601 scale factors? What's the interface standard? SMPTE 253M or Betacam or M-II?
  • Are there official designations for 8 cm discs (DVD-1, DVD-2, etc.?)

[7.2] Notation and units

There's an unfortunate confusion of units of measurement in the DVD world. For example, a single-layer DVD holds 4.7 billion bytes (G bytes), not 4.7 gigabytes (GB). It only holds 4.38 gigabytes. Likewise, a double-sided, dual-layer DVD holds only 15.90 gigabytes, which is 17 billion bytes.

The problem is that "kilo," "mega," and "giga" generally represent multiples of 1000 (10^3, 10^6, and 10^9), but when used in the computer world to measure bytes they generally represent multiples of 1024 (2^10, 2^20, and 2^30).

Most DVD figures are based on multiples of 1000, in spite of using notation such as GB and KB/s that traditionally have been based on 1024. The closest I have been able to get to an unambiguous notation is to use kbps for thousands of bits/sec, Mbps for millions of bits/sec, KB for 1024 bytes, MB for 1,048,576 bytes, and GB for 1,073,741,824 bytes.

[7.3] Acknowledgments

This FAQ is written and maintained by Jim Taylor. The following people have contributed to the FAQ (either directly, by posting to, or by me borrowing from their writing :-). Their contributions are deeply appreciated. Information has also been taken from material distributed at the April 1996 DVD Forum and May 1997 DVD-R/DVD-RAM Conference.

Robert Lundemo Aas
David Boulet
Espen Braathen
Wayne Bundrick
Roger Dressler
Chad Fogg
Dwayne Fujima
Robert "Obi" George
Henrik "Leopold" Herranen
Irek Defee
Kilroy Hughes
Ralph LaBarge
Martin Leese
Dana Parker
Geoffrey Tully


This document may be freely redistributed only in its entirety with authorship notice. Featured Partner:

 PW0-100 exams are very ideal Microsoft certification for the administration of any kind of communicative system including wireless LAN technology, radio technology, and standard wireless LAN security system of troubleshooting, networking designation, configuration, deployment and organizations. 70-229 exams are presentation of Microsoft SQL server 2000 enterprise edition with all manipulation of databases and application of all technological strategies. 642-511 exams are also known as Cisco secure virtual private networking system by encompassing all areas of Cisco VPN and Cisco VPN hardware applications with all safety measures. 640-861 exams are also recognized as Cisco internet working solution, having all practical functions of designing, planning and implementing of networking systems. 70-222 exams of Microsoft certification helps to accelerate the learning capacity of IT specialists by providing all updating knowledge and technical support.


This site is not related to the Microsoft Corporation in any way. Windows and the Windows logo are trademarks of the Microsoft Corporation. ActiveWindows is an independent site. The information and sources here are obtained from series of hard work & research.