[FFmpeg-user] Colorspace, clarifications; was: [Cin] FranceBB's LUT collection

[Paul B Mahol]

On Tue, May 20, 2025 at 4:53 PM Erik Dobberkau <erik.dobberkau at gmail.com>
wrote:

> > yuv420p10le(tv,bt2020nc/bt2020/smpte2084)
> >              \  \        \      \
> >               \  matrix   \      transfer
> >                range       primaries
> > Is the above _always_ the correct interpretation of the order?
> >
> > Here: https://ffmpeg.org/ffmpeg-filters.html#colorspace,
> > 1) Does "Input video needs to have an even size" really mean an even
> > number of rows?
> > 2) Is 'colorspace=space=<string>' really 'matrix'?
> > 3) What is 'colorspace=format=<string>'?
> > 4) The formats, whatever they are, are all yuv, so
> > 'colorspace=format=<string>' outputs yuv?
> > 5) Are all 'colorspace' outputs always yuv?
> >
>
> re 1): Both width and height must be even.
> re 2): set the matrix to use for the output. So yes.
> re 3): you can only pick yuvXXXpNN formats to set the subsampling and bit
> depth (XXX = { 420, 422, 444 }, NN = { [noValue -> 8 bpc], 10, 12 })
> re 4): Yes.
> re 5): Yes.
>
> From what I read in trac and Doxygen, I'd recommend you avoid using this
> filter if you can...
>

That would be incorrect/limited/ colormatrix.
colorspace is better, but not perfect.

Hopefully newer version of swscale in the making will address this.

_______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".
>