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FFmpeg's VP9 Decoder Faster Than Google's
An anonymous reader writes "A VP9 video decoder written for FFmpeg, FFvp9, now holds the title of being the world's fastest VP9 video decoder. FFvp9 is faster than Google's de facto VP9 decoder found in libvpx, but this doesn't come as too much of a surprise given that FFmpeg also produced a faster VP8 video decoder than Google a few years back with both single and multi-threaded performance."
I'm not an expert, but I'd say that when decoding video, frame drops caused by CPU overload sort of tend to be more noticable than a few decoding artifacts. At least that's how I always perceived it.
Ezekiel 23:20
The output is equivalent to what libvpx produces (as measured by MD5 on each output frame) on all files in the VP9 conformance suite.
A decoder is indeed normally specified with bit level output requirements. Two different decoders thus generate exactly the same decoded bitstream. Some hardware decoders do generate 'wrong' output, but it is either that or 3-4 times as much battery drain. It is also not so important when watching a fullHD movie on a 320x480 screen wether all 18 bits of output are right.
This is false. Decoding for modern video formats is strictly defined, and all decoders must produce bit-perfect output. You can add as many filters as you want after that, but that's a postprocessing step in the video player and has nothing to do with the decoder. Things like in-loop filters are strictly defined as part of the decoding process and must be there for the decoder to be considered correct.
Most users never encode a single video in their life. (Except for cameras on devices, and who is doing 4k video on thier phone these days?)
And if encoding takes 50x longer, that's 50x the resources Google needs to keep up with the work flow.
So you have it totally backwards.
Not to mention that we are talking about 4k-targetted codecs, so you should be comparing to H.265, not H.264. The additional computations for encoding H.265/VP9 are to reduce bandwidth requirements. If you don't care about bandwidth, feel free to generate a 5GB H.264 video.