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Frequently
Asked Questions This is the 6-May-98 revision of the FAQ for the alt.video.dvd
Usenet newsgroup. (See below for what's new.) Note: New DVD newsgroups have been created in the rec.video 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):
Contents
[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?
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:
* Must be supported by additional content on the disc. Some players include additional features:
[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?
[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:
Projected player releases:
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. 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 <http://www.unik.no/~robert/hifi/dvd/film1.html>, and for titles in Japan and Europe see <http://www.unik.no/~robert/hifi/dvd/film2.html>. Another extensive list of US titles is at <http://www.cybercomm.nl/~michiel/surround/dvd_list.htm>. New release lists and announcements are also available at <http://www.laserviews.com> 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:
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. 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) 2) CGMS 3) Content Scrambling System (CSS) 4) Digital CPS 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 <http://icib.igd.fhg.de/icib/it/iso/cd_13818-2/read1.html>). 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 <http://home.earthlink.net/~tlfordham/dvd.html>. [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.)
[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 <http://www.unik.no/~robert/hifi/dvd/film1.html>. A list of anamorphic titles is available at <http://www.laserviews.com/16x9.html>.
[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:
[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: [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?
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