Beyond the Hype: MPEG-4 and DivX
MPEG-4 and DivX make extravagant claims about video compression. We summarize the facts and not the hype.
Video on the internet could very well be the next big thing. Whether this means 10,000 channels of television or downloadable movies is uncertain. In order for video to become ubiquitous on the net, significant advances in video compression technology need to be made.

For example, an MPEG-2 movie requires approximately 6 gigabytes of storage which necessitates a DVD. What if we could fit the same movie on a 600 megabyte CD? This is the kind of claim that the recent MPEG-4 and DivX proponents would make.

At the LML, we have found that it is possible to put a full resolution movie on a CD using MPEG-4. So, this much of the hype is indeed true. However, the movie is not at the same quality standard as the original MPEG-2.

So, one would logically ask how much gain the MPEG-4 codec brings? At the same level of visual quality, how much can a movie be compressed using MPEG-4 beyond MPEG-2?

In our tests, a 6 gigabyte MPEG-2 movie can be reduced to a 4 gigabyte MPEG-4 version with negligible loss in quality. This is where DivX would sell their hype. Specifically, on their homepage they claim a 10 to 1 reduction at the same quality level. Hype!

MPEG-4 is an advance in video compression, but it generally is used in situations where the video is degraded to a point where obvious compression artifacts arise. You can put a movie on a CD with DivX, but you may not want to watch it afterwards.

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