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Old 12th October 2016, 19:24   #252  |  Link
benwaggoner
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Join Date: Jan 2006
Location: Portland, OR
Posts: 4,752
Quote:
Originally Posted by mzso View Post
Missed my second point too. If that was the most significant aspect they should have just released as soon as they got an agreement upon AV1. VP10 + throw in whatever is considered "mature" and gainful from the others. Then start optimizing the encoder/decoder.
For a codec (COMpressor, DECompressor, remember) you can't just "+ throw in whatever." Even if individual algorithms are mature, there are all kinds of changes to bitstream syntax that need to be made, probabilities of code values to be statistically analyzed and optimized in the bitstream, etcetera. AV1 is actually going pretty fast for what's aiming to be an industry standard codec. One little bug in the encoder that goes into the bitstream and then the decoder assumes can break clean-room optimizations and bake in non-optimal behaviors for a decade.

There are plenty of little weird things in the VPx history where a symmetrical bug in the encoder and decoder caused strange and painful limitations for 3rd party implementations. And anything like that in AV1 couldn't be fixed until AV2, because once you have decoders shipping in hardware, you need to stay compatible with them FOREVER. There are 10+ year old H.264 Baseline Profile decoders that modern encoders can make perfectly compatible streams for.

If a codec is just running as software in web browsers, things can be a lot more fluid. But not if it's going into fixed-function hardware! Or on any device that doesn't reliably get automatic firmware updates.
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