[FFmpeg-devel] Gamma function (was Re: [PATCH] lavc/pngenc: Support writing colorspace tags.)

Kevin Wheatley kevin.j.wheatley at gmail.com
Mon Mar 2 13:38:03 CET 2015

On Mon, Mar 2, 2015 at 12:17 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> the various colorspace options should pass from decoder over the
> video filter chain to the encoder and then muxer
> its best to change them from the command line through a video
> filter, this also ensures that the value reaching the encoder and
> muxer matches

I think I understand what you are suggesting in general, but in this
case this is an old metadata option that I don't imagine any other
format would want to propagate, it existed prior to the colr/nclc/nclx
and is  mostly superceded by that. I say mostly because the trc
options don't allow for arbitrary values like '2.6' for instance, and
we've also come across apps that need the gama atom setting to a value
and the trc left as 'unspecified' in order to correctly decode. even
when "rec709" would have been the correct value.

That was why I was thinking it should be a .mov muxer only option.


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