[Bf-blender-cvs] [0ea0ccc4ffd] master: FFmpeg: Fix H264 lossless render not lossless

[Richard Antalik]

Commit: 0ea0ccc4ffd573739aeb9e67e83dbfb3604887c7
Author: Richard Antalik
Date:   Wed Jun 2 21:24:09 2021 +0200
Branches: master
https://developer.blender.org/rB0ea0ccc4ffd573739aeb9e67e83dbfb3604887c7

FFmpeg: Fix H264 lossless render not lossless

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.

Reviewed By: sergey

Differential Revision: D11458

===================================================================

M	source/blender/blenkernel/intern/writeffmpeg.c

===================================================================

diff --git a/source/blender/blenkernel/intern/writeffmpeg.c b/source/blender/blenkernel/intern/writeffmpeg.c
index 60c216a8401..218552b0e74 100644
--- a/source/blender/blenkernel/intern/writeffmpeg.c
+++ b/source/blender/blenkernel/intern/writeffmpeg.c
@@ -729,6 +729,12 @@ static AVStream *alloc_video_stream(FFMpegContext *context,
     }
   }
 
+  /* Use 4:4:4 instead of 4:2:0 pixel format for lossless rendering. */
+  if ((codec_id == AV_CODEC_ID_H264 || codec_id == AV_CODEC_ID_VP9) &&
+      context->ffmpeg_crf == 0) {
+    c->pix_fmt = AV_PIX_FMT_YUV444P;
+  }
+
   if (codec_id == AV_CODEC_ID_PNG) {
     if (rd->im_format.planes == R_IMF_PLANES_RGBA) {
       c->pix_fmt = AV_PIX_FMT_RGBA;