[FFmpeg-devel] [PATCH]Add a 4444 profile to a prores encoder

Robert Krüger krueger at lesspain.de
Fri Sep 14 09:20:05 CEST 2012

On Thu, Sep 13, 2012 at 7:08 PM, Derek Buitenhuis
<derek.buitenhuis at gmail.com> wrote:
> On 13/09/2012 10:57 AM, Robert Krüger wrote:
>> Of course but since we know ffmpeg doesn't write the alpha information
>> into the file (at least that's my understanding but that could be
>> verified by directly transcoding a PNG with alpha to prores, which I
>> haven't done yet), the only remaining thing to check is whether chroma
>> subsampling looks ok when Quicktime decodes the file. At least that is
>> how I understood Carl.
> Sorry, I thought you were referring to the 4444 profile.
Hmm, now I'm not sure I understand. I was indeed referring to the 4444
profile, which currently, as I tried to describe above and in trac
#1728, kills the alpha, and sets all pixels to 100% opaque regardless
of the source material's alpha values.

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