[FFmpeg-devel] The -colormartix has trouble setting bt709

[Michael Niedermayer]

On Sat, Nov 02, 2013 at 09:26:31AM -0500, David Favor wrote:
> Summary.
> 
> I have a video clip which fails to play on Roku devices.
> 
> The problem appears to be colormatrix related parameters are NULL.
> 
> Forcing colormatrix to bt709 allows the video to play + the only way
> to do this appears to be using x264 options.
> 
> Problems...
> 
> 1) video is missing the following parameters. video plays when these
>    parameters are set to BT.709 via -x264opts below.
> 
>    Color primaries                          : NULL
>    Transfer characteristics                 : NULL
>    Matrix coefficients                      : NULL
> 
> 2) ffmpeg -vf colormatrix=src:dst seems to have no idea how to do a
>    conversion from a null colormatrix to another colormatrix

see:
[FFmpeg-devel] [PATCH] avfilter/vf_colormatrix: Support using the source AVFrame colorspace if none is specified
this makes it possible to use a unspecified source matrix and take
the actual source one

you can also see how the matrix type is passed around in that patch
if you want to extend the output side of the filter to pass its
output type to x264

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Republics decline into democracies and democracies degenerate into
despotisms. -- Aristotle
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