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

Stefano Sabatini stefasab at gmail.com
Sun Jul 22 10:18:30 CEST 2012

On date Saturday 2012-07-21 10:57:40 -0700, Steven Robertson encoded:
> 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.

Check av_image_get_linesize(), av_image_fill_linesizes() in
libavutil/imgutils.h, they should already provide the functionality
you need.

Anyway I'll apply this version, and eventually send a separate patch
for making use of it (if you won't beat me at it).

FFmpeg = Fantastic & Faithless Magical Philosofic Experimenting Gigant

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