[FFmpeg-devel] [PATCH] Add alphaextract, alphamerge filters

Steven Robertson steven at strobe.cc
Sat Jul 21 19:57:40 CEST 2012

On Fri, Jul 20, 2012 at 2:29 AM, Stefano Sabatini <stefasab at gmail.com> wrote:
> On date Thursday 2012-07-19 21:43:31 -0700, Steven Robertson encoded:
>> On Thu, Jul 19, 2012 at 12:56 AM, Stefano Sabatini <stefasab at gmail.com> wrote:
> [...]
>> > Also why are you copying the entire line, rather than just the image
>> > data?
>> So that the filters will work with 16-bit data just by extending the
>> pad configuration (which I may look into soon).
> Can you elaborate on this (and provide an use case)?

Sure. I'd like to use H.264 Hi10 profile with this technique to
increase the dynamic range of the content that I'm sending to clients
via the alphamerge/alphaextract path, and it looks like the right
answer for getting that data in and out of FFmpeg is to use
16-bit-per-channel depth formats. I haven't tested this, since I
haven't updated my tools to generate 16-bit content yet, so I wanted
to leave the simpler solution of copying entire lines in until I can
add and test the logic of determining bit depth, line width,
endianness, etc in a later patch.

> Patch looks good.

Awesome, thanks for everyone's help reviewing it.

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