[FFmpeg-user] HD > SD Down-Convert Prores Color

[Kevin Wheatley]

I should have paid more attention to your command line, in that case
you are going between the same pixel format and I'm not sure that the
use of the scalar for converting between different colour difference
encodings will actually do anything as I believe it only considers
using the matrices if the pixel formats go between a difference
encoding and RGB.

Going between two encoded video signals you might have to use the
colour matrix filter, to get 'correct' behavior.

Still won't stop some decoders making assumptions, though.

Kevin