FFmpeg is frequently used by different studios for encoding their media, however the documentation for ffmpeg is often poor, or cryptic so its often harder than it should be to come up with a good starting point. We are aiming to come up with recommendations for different scenarios as well as document what the different flags are doing with the aim to make this easier to get to a good baseline.
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| 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 | |||
| -profile:v 4444 is equivalent to -profile:v 4 | ||||
| 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 | ||
| Prores 422 HQ | Some FFMpeg commands I need to remember for converting footage for video editing. http://bit.ly/vidsnippets · GitHub |
| ||
Note the -profile:v 3 is equivalent to -profile:v hq | ||||
VMAF
I did explore using VMAF - Video Multi-Method Assessment Fusion as a way to quantify the compression, the notes for setting this up are below, however I think we are going with a fairly high compression factor , so I think this is probably not really going to help us much.
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The above gets the underlying data stored correctly, but there are additonal metadata flags that can be set that are interpreted by some players, these are the NCLC color tags for color primaries, transfer function and conversion matrix. (See: https://developer.apple.com/documentation/avfoundation/media_assets_and_metadata/sample-level_reading_and_writing/tagging_media_with_video_color_information )
" -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 1 "
-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.