Feature Request - Add 4:4:4 as a chroma subsampling option

Given this is an archive suite, I was surprised to see no option for a lossless colour capture.

Looking at part of the ffmpeg command generated (pasted below) raw_format yuv422p10.

I am aware that analog sources also have a form of subsampling by limiting signal bandwidth, my concern here though is not around what the source has, but generation loss from using 4:2:2. The original signal has a reduced chroma already, then we reduce it some more using 4:2:2 and then we edit it and reduce it some more, then export it again reducing it etc. The right answer is to limit this reduction at the start, as its captured, not later on down the track.

I think there is a widespread misunderstanding that the subsampling method is akin to one of those children's toys where you put the right letters into the right holes and therefore if we allow 4:2:2 in the container it will provide enough holes for the analog chroma system to fit into - which is dead wrong. (Especially) with low resolution video (and analog consumer low resolution video at that) which already exhibits chroma bleed / drift around the edges etc, 4:2:2 is just making that worse by being a second generation subsample - especially around the already problematic edges. I want to point out here one point of confusion, that the visible loss of 4:2:2 in 4k or 8k or even 1080p video is a lot less than with analog 480i / 576i simply due to the effective size of a pixel in the analog formats - and this is not even taking into account that it's interlaced.

I note two versions of Prores 4:4:4 are provided in blackmagic media express, which can provide an alternative in the interim, though I'd much rather use ffv1.

More info on subsampling: https://en.wikipedia.org/wiki/Chroma_subsampling

I don't think it would be hard to add this simple option into the mix right?

Thanks.

`Capture-Record command: /opt/homebrew/opt/ffmpegdecklink/bin/ffmpeg-dl -nostdin -nostats -timecode_format none -loglevel info -f decklink -draw_bars 0 -audio_input embedded -video_input sdi -format_code pal -channels 8 -audio_depth 32 -raw_format yuv422p10 -i UltraStudio Recorder 3G -map_metadata 0:s:v:0 -color_primaries bt470bg -color_trc bt709 -colorspace bt470bg -color_range mpeg -metadata creation_time=now -movflags write_colr -c:v ffv1 -level 3 -g 1 -slices 4 -slicecrc 1 -c:a pcm_s24le -metadata:s:v:0 encoder=FFV1 version 3 -filter_complex [0:v:0]setdar=4/3; [0:a:0]pan=stereo| c0=c0 | c1=c1[stereo1] -map [stereo1] -f mov /Users/username/Tape/videofile_ffv1.mov -an -f framemd5 /Users/username/Tape/videofile_ffv1.framemd5 -c copy -c:a pcm_s24le -map 0 -f matroska -write_crc32 0 -live true -`