[FFmpeg-devel] [PATCH] swscale/arm: add ff_nv{12, 21}_to_{argb, rgba, abgr, bgra}_neon

[Clément Bœsch]

On Thu, Nov 19, 2015 at 11:48:53AM +0100, Clément Bœsch wrote:
> From: Matthieu Bouron <matthieu.bouron at stupeflix.com>
> 
> Signed-off-by: Matthieu Bouron <matthieu.bouron at stupeflix.com>
> Signed-off-by: Clément Bœsch <clement at stupeflix.com>
> 
> ---
> The function takes about 29ms with a 1080p source (testsrc2) on a
> cortex-a8. Though, 16ms (more than half the time!) is spend in the vst2
> call. Any suggestion on how to speed up this?
> 
> Also, the reference code seems to cause some kind of ringing, while our
> ASM doesn't:
>   http://b.pkh.me/nv12-rgba-ref.png
>   http://b.pkh.me/nv12-rgba-neon.png
> 
> Last, we noticed that the y_offset is scaled to 1<<9 for some reason we
> couldn't figure out. Hopefully we're doing it correctly here.
> ---
>  libswscale/arm/Makefile           |   3 +-
>  libswscale/arm/swscale_unscaled.c |  62 +++++++++++++++
>  libswscale/arm/yuv2rgb_neon.S     | 162 ++++++++++++++++++++++++++++++++++++++
>  libswscale/swscale_unscaled.c     |   4 +-

Applied with a little adjustment: we added the width%16 constraint. See
comment in the commit for details.

Thanks,

-- 
Clément B.
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