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Old 9th January 2019, 17:37   #34  |  Link
benwaggoner
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Join Date: Jan 2006
Location: Portland, OR
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Quote:
Originally Posted by Blue_MiSfit View Post
QFT! VC-1 was some great stuff for sure. Microsoft was ahead of the game for awhile here
Yeah, peak MIPS-per-pixel for decode were a lot lower than the H.264 worst case. And there were some great encoder implementations with advanced adaptive deadzone and other features. And hey, 720p24 SW and DXVA playback in the early 2000's!

But Moore's law turns as always, and as computers got fast enough and HW decoders were deployed to handle multiple ref frames, b-frame weighted prediction, and the more complex in-loop deblocking of H.264, and CABAC, the SW decode advantages stopped mattering. And the explosion of torrented video piracy, and all those quality obsessed video pirates wailing away on a huge variety of real-world content in x264 made x264 increasingly hard to beat for lots of real-world VBR content. Psychovisual tuning is more important than any particular bitstream feature! And x264's popularity lead to a lot of investment in performance, with single-slice parallelism and advanced vectorization, which eliminated any encoder speed penalty.

I think a xVC1 would have been quite competitive (using CRF and psy-rd etcetera but outputting to VC-1)

We saw some movie studios using VC-1 for Blu-ray titles for years after Microsoft stopped developing the technology, because the tools for that use case were better than what was available for H.264 (x264 didn't really offer operator-friendly hand-tuned high bitrate encoding). Some of that was probably because of the xdither dithering tool, however, which wasn't codec-specific

A decade ago the codec people at Microsoft thought that VC-1 could have remained competitive with H.264 if:
  1. A stronger H.264-style in-loop deblocking filter was available
  2. The (in-standard!) optional postprocessing filtering was used
  3. Encoder development investments were continued

I'd probably add CABAC to the list as well, although VC-1's entropy encoding was IIRC better than CAVLC in practice.
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