[FFmpeg-devel] [PATCH] swscale alpha channel support

Cédric Schieli cschieli
Mon Feb 23 16:16:44 CET 2009


2009/2/23 Michael Niedermayer <michaelni at gmx.at>

> On Mon, Feb 23, 2009 at 02:15:26PM +0100, C?dric Schieli wrote:
> > 2009/2/21 Michael Niedermayer <michaelni at gmx.at>
> >
> > > On Sat, Feb 21, 2009 at 08:53:53PM +0100, C?dric Schieli wrote:
> > > > 2009/2/21 Jason Tackaberry <tack at urandom.ca>
> > > >
> > > > > On Sat, 2009-02-21 at 12:49 +0100, C?dric Schieli wrote:
> > > > > > Attached is another patch which factorizes some code in
> > > > > yuv2rgb_template.c
> > > > > > to ease further yuva2rgb patch.
> > > > >
> > > > > Rather than reading the patch I'll be lazy and just ask: with this
> > > patch
> > > > > applied, will yuv to rgb32 now set the alpha channel to 0xff
> instead of
> > > > > 0x00?
> > > >
> > > >
> > > > No, the aim of the patch is to use an existing alpha channel (from
> > > > YUVA420P).
> > > > But I agree that setting 0xff when "creating" an alpha channel would
> be
> > > more
> > > > useful than setting 0x00 as for now. I've already made a patch that
> does
> > > > just this (for mmx unscaled yuv420p->rgb32 and unscaled
> rgb24->rgb32).
> > > > I can send it for review if changing such a "default" behaviour is
> ok.
> > >
> > > you can
> > >
> >
> > The first patch (sws_yuv2rgb_factorize.patch) brings a little more
> > factorization in prevision of the yuva2rgb patch. It is also a
> prerequisite
> > for the second patch (sws_default_alpha_value.patch) which substitute 255
> to
> > 0 as a default value for alpha channel throughout the code.
>
> patches ok assuming they either
> * dont changes striped objects
> * have been tested (that is all changed code paths have been checked
>  in some way)
>

The factorize patch doesn't change the object files.

The second one missed one hunk in yuv2rgb2.c (updated patch attached)
Every code paths I can think of has been tested : any combination of
mmx/nommx, unscaled/scaled, fast_bilinear/bilinear/bicubic, +-bitexact,
+-full_chroma_int, rgb555/rgb565/rgb24/bgr555/bgr565/bgr24
only tested on x86_32 though


Regards,
C?dric Schieli
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