[FFmpeg-devel] [PATCH] Make decoding alpha optional for some codecs.

Mark Himsley mark.himsley at gmail.com
Thu Sep 19 11:32:08 CEST 2013

On 18 September 2013 13:04, Robert Krüger <krueger at lesspain.de> wrote:

> and basically every video player. E.g. quicktime displays full
> transparency in Prores4444 as black and so does FCP.

You have to decode the alpha to use the alpha mask any picture content
which is under transparent regions.

You cannot display the video correctly without multiplying the alpha
with the video content - unless the alpha is 100% across the whole
picture, which you don't know until you've decoded the alpha..

Mark Himsley

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