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Originally Posted by kurkosdr
PS: It would seem weird to me that MPEG would go through all the effort of defining MPEG4 ASP and breaking compatibility with MPEG2 without at least some kind of significant improvement in the coding tools offered.
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MPEG-4 part 2 was a disappointment. While it was better than MPEG-2, particularly for lower bitrates and resolutions, it wasn't so much better for 480i/576i that broadcasters were motivated to replace the millions of set top boxes to get a ~20% bitrate reduction. Plus there were IP ambiguities that made big bets by big companies seem unwise for the first few years.
Dark Shikari had a great insightful post about the design defects in p2 ASP somewhere I can't find. A couple issues I recall is that the requirement that adaptive quantization go up and down by even numbers relative to a previously determined frame QP was a challenge and annoying to optimize. And Global Motion Compensation could really only save something like 1 bit per frame. Hopefully someone else can dredge it up.
The broadcast market back then is what sold encoders, and therefore drove encoder development. MPEG imagined a big competitive ecosystem of vendors trying to squeeze out an extra 1% here and there to win contracts. That's what helped make MPEG-2 as good as it was, and later provided the many years of continuous improvement of H.264 and HEVC.
MPEG-4 Pt 2 never got that kind of love, both due to, and a cause of, its relatively small paying market.
Also, the streaming market back then was dominated by the proprietary QuickTime, Windows Media, and RealVideo. By the time they had had robust Pt 2 support, better codecs were available.
Lastly, as it was pretty obvious that Pt2 was in trouble, H.264 (MPEG-4 Pt 10) development was accelerated and arrived a lot sooner than the typical 10 year gap between major MPEG codecs, had obviously superior compression efficiency, and had a simple licensing regime. That's what broadcasters targeted, and what the encoder vendors all pivoted to competing on. The commercial market for H.264 encoders was quickly 100x bigger than the Pt 2 market ever was, which funded a lot of encoder developers. And then x264 happened with a remarkably brilliant set of developers and a big global audience competing on encoding fast and beautifully and providing a much broader base of feedback and fine tuning than any encoder before it ever got. It's weird to think that traditional codec development back then didn't even look at animation content!