FFmpeg: Fix H264 lossless render not lossless
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Authored by Richard Antalik (ISS) on Jun 2 2021, 2:04 AM.

Details

Reviewers

Sergey Sharybin (sergey)

Commits

rB0ea0ccc4ffd5: FFmpeg: Fix H264 lossless render not lossless

Summary

While encoder parameters for lossless encoding are set correctly,
output is not lossless due to pixel format being set to
AV_PIX_FMT_YUV420P which is inherently lossy due to chroma subsampling.

This was reported in T61569 and was merged to T57397, but there were
2 bugs - one for encoding and one for decoding.

Set pixel format to AV_PIX_FMT_YUV444P when rendering lossless H264
files. This format isn't available in codec->pix_fmts[0] and it looks,
that it has to be hard-coded.

Diff Detail

Repository

rB Blender

Branch

master

Build Status

Buildable 14887
Build 14887: arc lint + arc unit

Event Timeline

Richard Antalik (ISS) requested review of this revision.Jun 2 2021, 2:04 AM

Richard Antalik (ISS) created this revision.

Harbormaster completed remote builds in B14887: Diff 37709.Jun 2 2021, 2:04 AM

Evan Wilson (EAW) awarded a token.Jun 2 2021, 8:52 AM

Sergey Sharybin (sergey) accepted this revision.Jun 2 2021, 9:31 AM

This revision is now accepted and ready to land.Jun 2 2021, 9:31 AM

Hmm, isn't this true for VP9 as well?
Wouldn't you want to do this for other codecs besides H264?

In D11458#293216, @Sebastian Parborg (zeddb) wrote:

Hmm, isn't this true for VP9 as well?
Wouldn't you want to do this for other codecs besides H264?

Will check this

Right so this was true for VP9 too. I was thinking if there is a better way to express this in more universal way, but I am not sure. Worst case would be that unsupported pixel format would be set.
Also VP9 doesn't have rd->ffcodecdata.flags & FFMPEG_LOSSLESS_OUTPUT set, so I have used context->ffmpeg_crf == 0 now which isn't quite readable.

Will check if this can be fixed easily.