...
- An excellent starting point for this is: https://trac.ffmpeg.org/wiki/colorspace
- https://github.com/RxLaboratory/DuME/blob/master/src/FFmpeg_COLORS.md
- https://medium.com/invideo-io/talking-about-colorspaces-and-ffmpeg-f6d0b037cc2f
Notes
The big issue here is that by default if you start converting images to another format, and ffmpeg cannot determine the colorspace it will default to bt601. So many of the flags below are to:
A: Tell ffmpeg that the source media is in fact bt709
B: Add the metadata to the output, so that other future conversions also know how to convert it back.
C: Do as clean a conversion from RGB to YUV as possible.
Example Usages
| Name | Source | ffmpeg flags | Description |
|---|---|---|---|
| ffmpeg colormatrix | https://trac.ffmpeg.org/wiki/colorspace | -pix_fmt yuv444p10le -sws_flags spline+accurate_rnd+full_chroma_int -vf "colormatrix=bt470bg:bt709" -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 1 | 8bpc only |
The sws_flags are needed for the RGB to YUV conversion. -color_range 1 # mpeg see: FFmpeg/pixfmt.h at master · FFmpeg/FFmpeg · GitHub -colorspace 1 # BT709 FFmpeg/pixfmt.h at master · FFmpeg/FFmpeg · GitHub -color_primaries 1 # BT709 FFmpeg/pixfmt.h at master · FFmpeg/FFmpeg · GitHub -color_trc 1 # bt709 FFmpeg/pixfmt.h at master · FFmpeg/FFmpeg · GitHub - Color Transfer Characteristics. | |||
| ffmpeg colorspace | https://trac.ffmpeg.org/wiki/colorspace | -pix_fmt yuv444p10le -sws_flags spline+accurate_rnd+full_chroma_int -vf "colorspace=bt709:iall=bt601-6-625:fast=1" -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 1 | Supports 10bpc and 12bpc, SIMD (faster), better quality than colormatrix. |
...
| Name | Source | ffmpeg flags | Description | Size |
|---|---|---|---|---|
| colorspace_yuv444p10le | https://trac.ffmpeg.org/wiki/colorspace | -c:v libx264 -preset placebo -qp 0 -x264-params "keyint=15:no-deblock=1" -pix_fmt yuv444p10le -sws_flags spline+accurate_rnd+full_chroma_int -vf "colorspace=bt709:iall=bt601-6-625:fast=1" -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 1 | ||
| Prores 4444 | -c:v prores_ks -profile:v 4444 -qscale:v 1 -pix_fmt yuv444p10le -sws_flags spline+accurate_rnd+full_chroma_int -vf "colorspace=bt709:iall=bt601-6-625:fast=1" -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 1 | |||
| shotgun_diy_encode | https://support.shotgunsoftware.com/hc/en-us/articles/219030418-Do-it-yourself-DIY-transcoding', | -vcodec libx264 -pix_fmt yuv420p -g 30 -vprofile high -bf 0 -crf 2 | ||