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MPEG-4

Contributed By Glen Berry

If you were not already aware, MPEG-4 is the next big thing. Ever since the explosion of Mp3 (MPEG Layer 3), Internet experts have been predicting that it would only be a matter of time before a new algorithm would emerge that would be as efficient at compressing video as MP3 is at compressing audio. That compression method is here in the form of MPEG-4, a radical new algorithm that can reduce a video file to 1/12th of its original size. The potential is mind-boggling and has all the promise of revolutionizing the film industry in many of the same ways MP3 is changing the music business. However, like Mp3, MPEG-4 faces a number of technical, legal and political stumbling blocks on its way to popular use.

History of MPEG

MPEG, the Motion Pictures Expert Group, was formed in 1987 as an international group of industry experts dedicated to the development of standards for digital audio and video.

The first standard developed by the organization, MPEG-1, was released in 1992 and targeted video for CD-ROMs. Although common in the Far East, MPEG-1 and Video Compact Discs (VCD) saw little popularity in North American markets. Because of the low resolution (352x288 pixels) and video quality, MPEG-1 was only viable for low data rate CD-ROMs and some Internet applications. Incidentally, if you are using a Windows 95/98/2000/NT machine, you already have a native MPEG-1 software decoder built into your operating system.

In November 1994, MPEG-2 was introduced as a successor to MPEG-1. This format supported full screen (720x576) resolutions and the video was much higher quality. Many non-linear editing systems and modern capture cards work with MPEG-2 as a native file format. DVDs (Digital Video Discs) also utilize this MPEG-2 standard for playing movies on consumer systems. The compression rate of MPEG-2 was marketed as being 15% more efficient than MPEG-1 but the file size was still enormous by comparison to any other type of file.

Contrary to popular confusion, MP3 is not MPEG-3. In addition to the all-important video signal, MPEG-2 also contains three audio layers. Each of the layers is encoded with progressive complexity, with Layer I being the least complex and Layer III being the most complex (and the most efficient). Layer III produces the smallest file sizes, perfect for MP3 and the slow data transfer rates of an Internet Connection. Users pay the proverbial price for this compression with an increased drain on computer resources when encoding (recording) and decoding (playing) MP3 files.

What is MPEG-4?

The newest format was released by the MPEG group only as recently as December 1999 and employs a radical, new, object-oriented compression algorithm. In human-speak, MPEG-4 takes a completely different approach to compressing video than its predecessors.

MPEG-2 (as well as Quick time, Real Video and AVI) operates by sending a stream of images, frame by frame, from the server (distributor) to the client (consumer). Each individual frame is a rather large file, so transferring 30 of these frames every second (the rate required for full motion video) is very slow and cumbersome.

MPEG-4 departs from this by dividing the movie into separate objects in much the same way that a Flash animation works. Initially, the Internet site sends the data needed to draw the elements (characters and backgrounds) to your computer. Once the objects that need to be displayed are defined, the player simply requires a set of instructions to describe how these objects should interact together on your screen. Downloading the movie would then simply be a continuing process of downloading new objects (The Mad Scientist that appears in Scene 3) and the constant flow of instructions for how these objects should play across the screen. By only sending the instructions for objects when they change, the amount of data can be reduced to 8% (1/12th) of the original!

Applications

The first obvious usage is streaming video from websites. In the past, the problem with streaming movies across the Internet has always been a matter of bandwidth. Even the fastest corporate data connections can barely support video streams of marginal quality. This stumbling block has prevented would-be Net casters from serving up anything more than video that was jerky, poor quality and in a postage stamp-size frame.

Now that the video can be compressed to a fraction of its original size, bandwidth is no longer the bottleneck. Full motion, full screen, high resolution video is projected to require from 5 to 10 Megabits per second, which is still too much of a bandwidth requirement. However, with a few tweaks to the frame rates and size, high quality Internet video will be a reality. The ability to broadcast video at extremely low data rates could also mean a break-through for wireless applications.

Another exciting possibility is the distribution of theatrical length films on a CD. A movie that would normally take up 9GB on a DVD can now be compressed down to a nominal 700MB with little compression loss. That is, if the movie takes up all 9GB of a DVD. Most films come with several different versions on a DVD, which would mean that fitting a film onto a CD would be a snap. Although DVD burners have dropped considerably in recent months (models are now available for $3000-3400 US), CD burners are already in wide spread use and can be had for a few hundred dollars. This puts home distribution of high quality films in the hands of nearly anyone with a home computer.

MPEG-4 also has the advantage of clearing the field of competing proprietary formats such as Quick time, AVI and Real Networks. MPEG-4 has the potential to relieve the public of the annoyance of installing three different media players that refuse to support competing formats.

MPEG-4 also opens up the potential for more exciting technological developments in the future. The MPEG group describes MPEG-4 as a multimedia platform, designed to blend animation, text and video together into one format. The object-oriented nature of the format itself lends itself well to user interaction. For example, a spinning cube on the screen could be manipulated with a mouse or other pointing device to change the outcome of a movie.

Drawbacks

As with all things, MPEG-4’s biggest strength may be its greatest weakness. Although the compression method is highly efficient, it is also very complex. This means that it requires a great deal of processor time to encode the file, i.e. alter it from a MPEG-2 format to MPEG-4. Although a run-of-the-mill PC might take 6 to 12 hours to encode a feature length film, this not that great of a concern since it places the processor burden on the distributor who can usually afford the newest equipment. However, it also requires a great deal of processor power to view the video. The public, who do not collectively have the latest and greatest computers, must absorb this burden. Although it is too early in the development of MPEG-4 to tell how much processor time is needed, it is a serious concern.

Another drawback is the availability of players. Fortunately, free DivX players are available for download (http://divx.vcdguide.com/codec.php3). DiVX is a modified version of Microsoft's MPEG4V3 implementation, not related to the now defunct Circuit City DiVX. In addition the Microsoft Windows Media Player can be "modified" to play DivX movies. However, there is very little documentation or support for these players.

As in the early days of MP3s, finding a reliable source of movies is difficult at best. DVD rippers and DivX encoders are available but creating and distributing copyrighted films is just as illegal as it was when MP3 hit the scene. Your best bet at finding a copy of your favorite film is trading with a person called MoViePHreAK in late night chat room. Until the major distributors (Hollywood) determine how to control the format and prevent piracy, content will be scarce and of marginal quality.

Future of MPEG-4

If MP3 provides us with any kind of model of what to expect, the future will be very exciting. Once a rogue company or a 16 year-old high school student develops a “killer app” to share MPEG-4 movies, trading of illegal movies will spread like wildfire. As the demand explodes, the hired legal guns of the movie industry will file as many lawsuits as possible in a futile attempt to stop the tide of a popular movement. The industry will use their various trade collectives to bring pressure to bear on politicians, who will be unable to pass laws fast enough to “keep the genie in the bottle”.

Keep in mind that the movie industry has kept a close eye on what changes MP3 is bringing to the music business. It is likely that the industry has anticipated this scenario and is frantically working on a legal or political remedy to stop this format dead in its tracks. Of course, the studios have already demonstrated an astounding inability to recognize changing market conditions and have refused to acknowledge the threat and promise of the Internet. They might just let this slip by without much action except for a few threatening lawsuits until its too late.

Regardless of the outcome of the piracy issues, the format opens the door for the ultimate opportunity for the independent filmmaker: self-distribution. The potential that was hinted at with the Blair Witch phenomenon can now be realized with MPEG-4. The technology may not be there right now but it will develop quickly so keep your eyes on the early adopters. In the meantime, start downloading!

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