How are movies stored on DVD discs?

Even though the storage capacity of a DVD is huge, the uncompressed video data of a full-length movie would never fit on a DVD. In order to fit a movie on a DVD, you need video compression. A group called the Moving Picture Experts Group (MPEG) establishes the standards for compressing moving pictures.

When movies are put onto DVDs, they are encoded in MPEG-2 format and then stored on the disc. This compression format is a widely accepted international standard. Your DVD player contains an MPEG-2 decoder, which can uncompress this data as quickly as you can watch it.

A movie is usually filmed at a rate of 24 frames per second. This means that every second, there are 24 complete images displayed on the movie screen. American and Japanese television uses a format called National Television Standards Committee (NTSC). NTSC displays a total of 30 frames per second; but it does this in a sequence of 60 fields, each of which contains alternating lines of the picture. Other countries use Phase Alternating Line (PAL) format, which displays at 50 fields per second, but at a higher resolution (see How Video Formatting Works for details on these formats). Because of the differences in frame rate and resolution, an MPEG movie needs to be formatted for either the NTSC or the PAL system.

The MPEG encoder that creates the compressed movie file analyzes each frame and decides how to encode it. The compression uses some of the same technology as still image compression to eliminate redundant or irrelevant data. It also uses information from other frames to reduce the overall size of the file. Each frame can be encoded in one of three ways:

• As an intraframe, which contains the complete image data for that frame. This method of encoding provides the least compression.
• As a predicted frame, which contains just enough information to tell the DVD player how to display the frame based on the most recently displayed intraframe or predicted frame. This means that the frame contains only the data that relates to how the picture has changed from the previous frame.
• As a bidirectional frame. In order to display this type of frame, the player must have the information from the surrounding intraframe or predicted frames. Using data from the closest surrounding frames, it uses interpolation, which is sort of like averaging, to calculate the position and color of each pixel.

Depending on the type of scene being converted, the encoder will decide which types of frames to use. If a newscast were being converted, a lot more predicted frames could be used because most of the scene is unaltered from one frame to the next. On the other hand, if a very fast action scene were being converted, in which things changed very quickly from one frame to the next, more intraframes would have to be encoded. The newscast would compress to a much smaller size than the action sequence. This is why the storage capacity of digital video recorders (which store video on a hard drive using the MPEG format) can vary depending what type of show you are recording.

If all of this sounds complicated, then you are starting to get a feeling for how much work your DVD player does to decode an MPEG-2 movie. A lot of processing power is required -- even some computers with DVD players can't keep up with the processing required to play a DVD movie.

http://www.howstuffworks.com/question596.htm

DVD replacing audio, video, computer discs all at once!

The compact disc, barely into its second decade of existence, could be on the road to extinction if the DVD lives up to its potential.

DVD s are already putting the final nails into the coffin of the venerable laser video disc and are starting to threaten the CD-ROM as well, so the audio CD may not be far behind.

Why? Supreme quality and extreme data storage.

Imagine watching "Amadeus" on your TV, with far better picture and sound than you ve ever gotten from your home theatre equipment before, then listening to the soundtrack album afterward  without changing either the player you re using or the disc you re playing. Imagine watching the latest adventures of the space family Robinson, then capping a leisurely surf of "Lost in Space" trivia with an interactive game accessed via your remote control.

You can do both  today. And you ll be able to do more tomorrow. Imagine buying your favourite recording artist s entire library on a single DVD disc!

Dynamite Value Disc?

DVD s are merely the next generation of CD s, using new technology to push CD storage into the stratosphere. For example, an audio CD holds about 74 minutes of digital sound, but a DVD (which is the same size as a CD) can allow something like 480 minutes. And while laserdiscs hold up to 60 minutes per side, you can stuff "Gone with the Wind" onto a single 5.25 inch DVD disc.

Whew!

The technology came from a couple of sources, including the ever-fertile corporate minds of Sony and Philips  the people who developed today's CD. Naturally, there was a different, competing version as well, from a consortium that included Toshiba and Time Warner  and for a while it looked as if the poor consumer would be stuck with yet another VHS/Beta (or PC/Mac) war.

Fortunately, the makers saw the light and a single system was introduced  though a competing technology called DIVX has recently reared its ugly head and could throw a monkeywrench into DVD s growth. More about that later &.

DVD has crammed into it just about any home theatre toy you could want, including Dolby Digital and/or DTS surround sound audio (six separate audio tracks: front left and right, centre, rear left and right, and subwoofer)  and there's so much room on a disc you can have movie soundtracks (and subtitles) in several different languages, with space to spare for commentaries, still pictures, "trailers", deleted scenes, etc.

The picture quality is the finest one can imagine this side of HDTV and audio quality is equally superb, whether you re watching movies or playing computer games. DVD players also make audio CD s sound simply magical, as if playing the old style discs doesn t even cause them to work up a sweat.

The Magic Behind the Medium &

DVD works similarly to CD s, in that a laser beam is reflected off a series of pits etched into the surface of a reflective disc, but DVD ups the ante considerably.

New generations of lasers use narrower wavelengths (less than a hundredth the width of a human hair, according to one source), so they can focus more precisely. This allows for smaller "pits" that can be spaced more closely together, all of which makes for vastly increased data storage capacity.

Not only that, but they can now take the CD's single layer of pits and put a second layer underneath it  and data can be crammed onto both sides of the DVD as well, making the format s storage potential positively skyrocket.

As if that weren t enough, the wizards behind this magic can also squeeze more video information into fewer pits, thanks to the same digital compression technology that's found in those little 24" satellite dish systems. Put extremely simply, this "MPEG 2" digital compression eliminates redundant information between movie/video "frames", saving space. So if a scene plays out in front of a relatively static background, for instance a hotel room, the fixed information (the room) is only stored once, while parts that change (characters  faces, positions, flying bullets, zooming spaceships), are stored as needed.

The Player s the Thing &

DVD players include all the features we ve come to know and love on CD and laserdisc players, including freeze frame, slo-mo, random access to tracks etc. Only Pioneer Electronics offers a DVD/laserdisc/CD combination player that plays all discs except CD-ROM s, but even the garden variety DVD player is perfectly happy with DVD movies and audio CD s, though as yet none of them play DVD or CD-ROM discs (the former of which are in extremely short supply anyway).

You ll soon be able to record your own DVD s, too. Recordable DVD's (DVD-RAM) are either available or coming soon from most major computer equipment manufacturers. Supposedly recordable up to 100,000 times, the discs aren t compatible with today s video DVD players, but with any luck this will change over the next few years.

Meanwhile, it s easy to imagine a day in the not-too-distant future, when DVD recorders (with built-in TV tuners and timers) have replaced your VCR  because once you ve seen the digital disc in action you ll never want to go back to the muddy, "dropout-laden" picture and "half-earsed" sound of videocassettes.

Rushing out in a buying frenzy &

But for now, DVD means movies, with some games and computer titles. Does this mean your CD player, CD-ROM drive, and laserdisc player are all obsolete?

Well, yes, but don't fret - as long as they keep working and you enjoy your current library they're never really outmoded. Besides, since DVD players are already following the trail blazed by their CD ancestors, units are getting better and cheaper all the time, so it won t hurt to wait a while (though there s no reason NOT to take the plunge right now, either!).

Early CD players really had only one advantage over today's: they were better built. Today's entry level players, plastic as they are, give terrific sound and more features than you're likely to use, and things should happen the same way with DVD s  though it s hard to imagine what other features the engineers can dream up for DVD players that will top what s already available!

Remember, too, that while movie titles are being released fast and furiously, it ll take years for there to be as much DVD software available as there is VHS or even laserdisc. After all, audio CD's are only now catching up with the libraries of the vinyl LP s (remember them?) they re replacing, and they ve been around for fifteen years.

Should you go ahead and buy that CD player you're been eyeing, knowing that there s a DVD player with your name on it just around the corner?

Well &

Low end CD players are still cheaper than low end DVD players, so if you re looking for an inexpensive audio-only solution, a CD player is still a good investment - for now.

DVD movie prices are generally a little higher than "priced to sell" videocassettes, though substantially lower than laserdiscs sold in Canada. Prices range from about $22 to $40 for top movie titles, though there s been a disturbing trend toward higher prices lately. Considering the quality you get, however, and the extra features crammed onto most movie discs, the software isn t really overpriced  yet.

But DVD is terrific. It deserves to be the next technological wave, and you really should get ready to ride it.

http://www.technofile.com/articles/dvd.html

Check out this TriPort CD player

If Michael Schumacher is 'the Man' for F1 fans or Big B is 'the Messiah' of millions, Bose music systems are 'the One' for music fanatics. And I am sure that any music lover will vouch for the quality of acoustics Bose delivers.

The Bose TriPort CD player, which I would say is bundled free with Bose headphones (binaural ear-cup type), is worth its cost. The headphones come with the 'just right' clarity of treble and a depth of bass and the end result - a very balanced pristine sound.

Most of us start listening to music when we're young, zero down on a genre(s) that speaks to you on a level that no other music does and inspires you move to the beat of your own music. Listening to music is a religious duty for many, including me. And here the most important part is the sound quality that only a good pair of headphone can give you.

With any other cheap set of earphones, I have always had to crank the volume up all the way and they would still distort the output. And so it was the sound quality of the Bose that sold me. They worked great on MP3 and personal CD players as well as home stereos, but I loved using them with my computer (where I store my treasure of 20GB of solid music).

On songs that carry more bass, for instance hip hop, I thought that there must be a subwoofer somewhere in the room. In classical and jazz pieces, I felt like I was in a concert hall with musicians. I've managed to see a few DVDs with these headphones on and was not disappointed.

Bose has built quite a reputation for its audio magic since they started in 1964. It's now taken for granted that when you purchase a product from Bose, you're not just purchasing a set of headphones or a radio, you're purchasing their years of research and design that come across as an advanced blend of components and technology. I have seen people who believe that Bose systems add character to vocal delivery.

Another nice aspect I found was the ergonomic design of the headsets, which keeps them remarkably comfortable and lightweight - they only weigh five ounces! The soft cushions gently enfold ears for hours of comfortable listening and the slim headband is fully adjustable.

The cushioned ear cups seal out sound, exploiting the spatial representation of sound. Which means that during intense listening sessions, home studio use, private late night jam sessions, and those times when you just want to focus on the music, they are your best friend.

Moving from headphones to the CD player, there's actually not much to talk about. It's a normal MP3 player. It has top loading, shock proof memory, and an LCD display. The best part is that it has an option to 'Add to my mix' which lets you select songs and add it in a separate directory.

This way you don't have to listen to a list of songs before zeroing in on your favourite one when you play the CD. The sales package comes with a carrying case and a headset cord extension (helps while connecting to PC)

Overall, it boasts of a great visual appeal with slick-looking design and high-tech finishes and at Rs 11,999 I think it's an aural treat.

http://in.rediff.com/money/2006/jan/07cd.htm

DualDisc, Take 2

A few months ago, I wrote about the audio industry’s new software format, the DualDisc. Most of what I had to say at that time was based on projection and speculation. I’ve since had some hands-on experience with DualDiscs, and this experience has led me to one new realization, and the ability to review some specific titles.

If you missed that first column and the DualDisc’s sporadic promotion, here’s the deal: This "new" format is really an amalgam of two well-established ones, the CD and the DVD. One side of a DualDisc is CD, the other DVD. This makes the disc compatible with almost all players and allows the inclusion of video and audio material on the same disc.

The end of standalone DVD-Audio?

DualDisc signals either the end of or a new beginning for the DVD-Audio disc. Whereas the competing high-resolution format can be played in a regular CD player, a DVD-A could be played only in DVD players. In addition, because most automobile players are still CD-only, DVD-As were incompatible with on-the-road listening. Considering the number of hours many of us spend in our vehicles, which have become virtual homes away from home, this is an important consideration. I was able to enjoy, for example, Patricia Barber’s hybrid Mobile Fidelity SACDs in high-resolution sound on my universal disc player at home, then take them with me to listen to in my car, where they offered solid CD reproduction. But such discs as the phenomenal DVD-A of the Big Phat Band could be enjoyed only at home.

But with one DVD-A side, DualDiscs can compete with hybrid SACDs. In fact, I no longer see the point in making discs that are solely DVD-A. Apparently Silverline, one of the largest producers of DualDiscs, agrees. The company had released the highly desirable Vanguard recordings of producer Seymour Solomon on DVD-A, including the complete Mahler symphonies with Maurice Abravanel and the Utah Symphony. They had gotten to Symphony 4, then announced that Symphony 5 would be released on DualDisc only, with one side 5.1-channel DVD-A, the other side CD. There will be no standalone DVD-A release. When I asked a Silverline exec if this was to be the future release pattern, he said, "Let’s see." Which to me means that Silverline will go with the flow. My guess is that, despite a recent spate of releases from the Universal Music Group, the DVD-Audio disc is dead -- a DualDisc can give a consumer virtually everything the DVD-A could, and can be played as a regular CD.

DualDiscs in the home and on the road

The DualDiscs I sampled worked splendidly. The best was a Silverline release of Abravanel’s luminous reading of Tchaikovsky’s The Nutcracker. The DVD-A side produced the best sound I’ve ever heard from this already good-sounding recording. It also gave me a few video features, including a still-frame archive, where I was pleasantly shocked to find a copy of a review I’d written for the now-defunct Laser Disc Gazette of this recording’s first CD release some ten years ago. The CD side played just fine in my car’s Alpine magazine changer. The only problem was that the CD side did not contain the complete ballet, due to time constraints imposed by the DualDisc format. Still, the CD provided a lot more music than the usual suite -- about two-thirds of the complete ballet.

Another disc, on the Lava label, offered Simple Plan’s Still Not Getting Any . . .

The DVD-A side played fine at home, with excellent sound, though the music -- each song seems a variation of the first -- wore somewhat thin. But when I put it in the car player, I found the tunes just right for a Thanksgiving drive along the Potomac. In this case, then, DualDisc to the rescue. The DVD-A side, by the way, contains some video, a still-frame archive, and a making-of featurette. The video on a DVD-A doesn’t have anywhere near the picture quality found on some of the best DVD-Vs, but it’s serviceable.

I then tried a Poncho Sanchez concert, Poncho at Montreux, on Silverline. The Latin jazz artist and his dynamic band sounded spiffy in 5.1 channels at home, and there was a video of one of the songs, as well as some artist photos. In the car, the disc gave me hi-fi sound that got me through a traffic jam smiling. And this disc exhibited yet another possibility for DualDisc: ROM content. I was able to pop the disc into my computer and get some extra features, including a download for personal use, had I desired it.

Contrary to some reports of damage to players resulting from playing DualDiscs, all the ones I had played without a hitch on any player into which I fed them: three home players, two universals, one CD player, and the car player. And as soon as the Big Phat Band title is released on DualDisc, I can enjoy it in my car as well as at home.

Down the road, I think we’ll see a genuinely new format in which a rotating software disc has nothing to do with things. Perhaps one of the new blue-laser systems will catch on, with high-resolution audio riding the coattails of the high-definition video they will provide.

But for the here and now, DualDisc is an innovative spin on present technology. Wisely shopped, the format can provide some interesting possibilities. Most important, it works. If you remember, as I do, the early days of stereo LP or CD, that’s saying a lot.

http://www.ultraaudio.com/opinion/20050201.htm

Sony halts production of CDs with copy-protection scheme

WASHINGTON — Stung by continuing criticism, the world's second-largest music label, Sony BMG Music Entertainment, promised Friday to temporarily suspend making music CDs with anti-piracy technology that can leave computers vulnerable to hackers.

Sony defended its right to prevent customers from illegally copying music but said it will halt manufacturing CDs with the "XCP" technology as a precautionary measure. "We also intend to re-examine all aspects of our content protection initiative to be sure that it continues to meet our goals of security and ease of consumer use," the company said in a statement.

The anti-piracy technology, which works only on Windows computers, prevents customers from making more than a few copies of the CD and prevents them from loading the CD's songs onto Apple Computer's popular iPod portable music players. Some other music players, which recognize Microsoft's proprietary music format, would work.

Sony's announcement came one day after leading security companies disclosed that hackers were distributing malicious programs over the Internet that exploited the anti-piracy technology's ability to avoid detection. Hackers discovered they can effectively render their programs invisible by using names for computer files similar to ones cloaked by the Sony technology.

Sony's program is included on about 20 popular music titles, including releases by Van Zant and The Bad Plus.

"This is a step they should have taken immediately," said Mark Russinovich, chief software architect at Internals Software who discovered the hidden copy-protection technology Oct. 31 and posted his findings on his Web log. He said Sony did not admit any wrongdoing, nor did it promise not to use similar techniques in the future.

Security researchers have described Sony's technology as "spyware," saying it is difficult to remove, transmits without warning details about what music is playing, and that Sony's notice to consumers about the technology was inadequate. Sony executives have rejected the description of their technology as spyware.

Some leading anti-virus companies updated their protective software this week to detect Sony's anti-piracy program, disable it and prevent it from reinstalling.

After Russinovich criticized Sony, it made available a software patch that removed the technology's ability to avoid detection. It also made more broadly available its instructions on how to remove the software permanently. Customers who remove the software are unable to listen to the music CD on their computer.

http://www.usatoday.com/tech/products/2005-11-11-sony-cds_x.htm

A Wish List re: Multichannel SACD & DVD-A

1. That both competing high-rez format camps would realize it is difficult enough for one format to make it commercially (especially in the present perilous economy) let alone two directly competing ones. Sony/Philips should think about some incentives they could offer the TimeWarner camp to drop DVD-A and support the only one of the two formats that offers true high-rez multichannel - SACD. (Don't make the Beta vs. VHS error all over again! Look at the huge success of DVD video when everyone got their act together!)

2. That manufacturers would quickly offer $300-range multichannel SACD players that also play DVD-Video, so that those who would be first-time DVD buyers could painlessly include SACD playback. (Yes, the new $400 Sony is a multichannel SACD but not a DVD-Video deck.)

3. That all multichannel players would henceforth offer a six-channel FireWire digital output or six coaxial outputs for use with new outboard multichannel DACS or complete processors/ receivers for ultimate high end sonic quality. (The software makers' fears of piracy are in danger of scuttling both formats in the high end world.)

4. That the separate LFE channel - fine for movies but inappropriate for music - be dropped in favor of six full-range channels. (See David Chesky's proposal in our July 2000 issue - in the Archives; though he eliminates the center front channel - with which we disagree.)

5. That complete bass management (in both directions) for all multichannel formats - high and low-rez - be included in all multichannel receivers and processors, including entry-level.

6. Since it is obvious that 5.1 surround sound for films is not suitable for SSfM (surround sound for music), and the system of one speaker per channel is limited, replace it with more flexible surround approaches in which the speakers tend to draw less attention to themselves. (B-format Ambisonics, for example, requires only 4 channels and can serve any number of speakers. Thus space is freed up for other mixes, longer playing times, a binaural headphone option or video. DTS and DD are OK, but wouldn't it be a kick to have ultimate multichannel SACD sound with our music DVD videos?)

7. That DVD-A players be designed for use by music-lovers who lack a video display in the same room or do not even own one! (Even the Sony 9000SE requires a monitor display in order to turn off progressive scan to improve SACD-only playback.) A simple front-panel display could handle this.

8. That Sony Music wake up and re-press all their SACD-Only discs as hybrid SACD/CD discs like everyone else.

9. That increased consumer acceptance of SACD outside of the high end - due to its multichannel abilities and lower price of players - will eventually bring down the price of SACD software to that of current standard CDs.

http://www.audaud.com/audaud/JUL01/wish.html

Sound Choices

Consumer confusion, marketing mistakes, and a dearth of authoring tools accessible to mid-size producers have hindered the growth of DVD-A and SACD, but the studios behind the audiophile formats have big plans for 2003.

Which of the new audio formats is superior—Super Audio CD (SACD) or DVD-Audio (DVD-A)?
It's all a matter of opinion. For record labels, the choice may be based on technical superiority or political alliances. For the audiophile consumer who actually understands what a DVD-A or SACD is, it really doesn't matter which they prefer because it's all about which titles are available, and that number's still quite small. At year's end, there were about 300 DVD-A titles on the market and around 100 SACD titles. By March 2003, it is expected that total U.S. third-party SACD titles will be 146, plus 113 hybrid multichannel discs. Both formats started to make a little noise at the end of 2002. On the one hand, Warner, EMI, and BMG all announced or affirmed their support of DVD-A with a range of new and catalog titles; BMG's DVD-A version of Elvis 30 #1 Hits on RCA was expected to be a hot seller during the holiday season. Sony and Universal, on the other hand, support SACD. EMI's Virgin released the 22-title "Rolling Stones Remastered" catalog series in the fall, the first release to create a real stir in that format.

Still, the labels and their distributors are having a hard time figuring out how to market either format. "Retail accounts are grappling with how they retail these new formats. They finally figured out that DVD-Video is big enough to have its own music section. But high-end audio stuff is lumped together," says Leslie Cohen, vice president of business development for Sony Music Entertainment. Cohen recounts one trip to a retailer who "had DVD-A and SACD all mixed together. It's okay to be side by side, but not mixed together. The poor consumer sees this huge section, but has no idea how to attack it." Then there are the big names like Circuit City and Best Buy that support hardware, but don't know what to do with the titles, so they shelve them with the players rather than in the music section. That's not the best way to sell discs, but Cohen admits that the formats need to be proven sellers before they command their own section in the battle for shelf space.

Both formats have a long way to go with regard to marketing and acceptance. And how many engineers really are savvy enough to put out a good product? Is DVD-Audio or SACD really being produced at the project studio level—like CD-Audio, DVD-Video, and DVD-ROM—or do both formats remain, production-wise, the province of the major music studios and their minions? And when, if ever, will the ascendancy of either format justify more small outfits throwing their hats in the ring? Then there's the nagging little question of how the heck DTS fits in. EMedia will attempt to put this all in perspective.

DVD-A
The official DVD-A Web site gives this as the format's definition: DVD-A "can provide a major advance in audio performance by providing the listener with advanced resolution stereo (two channels) and/or multichannel surround sound (up to six channels) music." DVD-A can provide dramatically higher-quality stereo sound than CD with a sampling rate of up to 192kHz compared to 44.1kHz for CD. DVD-A digital sound can be delivered with up to 24 bits of data, compared to 16 bits for the uncompressed pulse code modulation (PCM) CD standard. DVD-Audio discs cannot be played on a conventional CD player, though virtually every label releasing DVD-Audio discs includes tracks in the video zones of those discs that are compatible with all existing DVD-Video players. Audio CDs will play on DVD-Audio players just as they do on DVD-V players.

DVD-A titles are trickling in from some of the majors, including Warner, EMI, and BMG. As of December, Warner had about 75 titles on the market. But independent labels have perhaps been the most aggressive in pushing the format. For example, 5.1 Entertainment's goal was to have more than 100 discs, many of them new titles, by the end of 2002. Company president John Trickett has been very vocal in the press about DVD-A's benefits and, as a result, has perhaps been more instrumental than the majors in helping to launch the format. But, like virtually all the audiophile formats from gold masters to DAT, DVD-A hasn't captured the attention of the music-buying public.

Perhaps the biggest consumer awareness problem for DVD-A comes from the "DVD" in its name. When consumers hear DVD, they immediately think video; the popular press often makes the misconception worse by continuing to refer to DVD as Digital Video Disc. Instead of fighting the misconception, DVD-A creators are starting to use it to their benefit and promoting the idea that DVD-A can offer not only an audio-experience but, like DVD-V, can offer extras. In the case of an audio disc, video can be part of the extra content.

In an effort to clear things up for the consumer, record companies have come up with yet another cousin to DVD-A, which may in fact confuse the market more. The DVD Forum has set out to create a hybrid dual-layer CD/DVD-A disc that will play in all CD and DVD-A players. A good idea, perhaps, because right now DVD-A discs won't play in CD machines. But creating a CD/DVD-A format isn't as easy as it sounds. A hybrid disc requires changes to the Red Book CD specification. Warner, however, announced its support for this format at the end of last year. Another interesting way to push the consumer slowly into the DVD-A arena is to package a CD and DVD together, as done recently by RCA with releases from the Dave Matthews Band and the Foo Fighters, although admittedly these "bonus discs" are DVD-Video, not DVD-Audio. But RCA may see this as an intermediary step toward adapting listeners to receiving music content (with or without video component) on DVD discs. At presstime, BMG could not comment on the success of these projects. While practice makes perfect, it's true that authoring DVD-A is complex, and might be another reason the format has been slow to grow. There are navigation issues associated with it, for example. Authoring tools are becoming available, however, for manufacturers of these products, and it's relatively easy to make the trans- ition from authoring CD to authoring DVD-A.

http://www.emedialive.com/Articles/ReadArticle.aspx?ArticleID=5062