Many of the functions from avfilter/formats can return errors, usually AVERROR(ENOMEM).
This propagates the return values.
All of these were found by using av_warn_unused_result, demonstrating its utility.
Tested with FATE. I am least sure of the changes to avfilter/filtergraph,
since I don't know what/how reduce_format is intended to behave and how it should
react to errors.
Fixes: CID 1325680, 1325679, 1325678.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Previous version Reviewed-by: Nicolas George <george@nsup.org>
Previous version Reviewed-by: Clément Bœsch <u@pkh.me>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
This makes the sorting of the colors along an axis (r, g or b)
predictible, and thus testable under FATE. The performance is not really
an issue here since the function is called only once at the end and will
need to sort very small number of entries, so an alternative would be to
make the sorting functions (see DECLARE_CMP_FUNC()) fallback on another
axis in case of equality. This approach was actually simpler.
I don't know if there is any advantage in using a multidimensional sort,
but it will affect the final palette one way or another.
