From 0ea0ccc4ffd573739aeb9e67e83dbfb3604887c7 Mon Sep 17 00:00:00 2001 From: Richard Antalik Date: Wed, 2 Jun 2021 21:24:09 +0200 Subject: [PATCH] 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 --- source/blender/blenkernel/intern/writeffmpeg.c | 6 ++++++ 1 file changed, 6 insertions(+) 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;