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Old 21st January 2019, 19:26   #1385  |  Link
benwaggoner
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Join Date: Jan 2006
Location: Portland, OR
Posts: 4,771
Quote:
Originally Posted by foxyshadis View Post
It's not completely set in stone, but I really believe H.264/AVC might be the last codec easily encodable in pure x86/x64. lntel and AMD have agreed on some extensions to make H.265/HEVC and AV1 not suck quite as much, but the obvious direction is in GPU or fixed-function encoding.

HEVC is certainly encodable on x64, although 32-bit becomes impractical at high quality at very high frame sizes. The trend for even live encoding has been towards highly multithreaded CPU encoding. Fixed-function ASIC style hardware is too inflexible when there are SO many options for how to encode every block, with lots of psychovisual tuning to be done. The more complex codecs get, the more high quality encoders are on CPU. And arithmetic entropy coding really benefits from peak single-thread performance. I think there is hope for hybrid CPU/GPU/ASIC/FPGA models, but I don’t see professional quality encoding not to heavily use CPU anytime soon.

I don’t think there is anything intrinsically hard about AV1 for software encoding. If anything SW encoding could be easier than HW encoding due to parallelization limitations. The bigger issue is that VPx hasn’t had a truly competitive quality @ perf encoder in YEARS. And a reference encoder isn’t a great starting point, which libaom sort of is. If one wanted to build a quality @ perf optimized encoder from scratch, especially for low latency live encoding, I’d start by just implementing the mandatory features of a bitstream and then add features incrementally, seeing what their quality @ perf is. Starting with an encoder that HAS to use ALL codec features like a reference encoder does can be harder than going front the ground up.


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