[FFmpeg-cvslog] swscale: factorize DITHER_COPY()

[Christophe Gisquet]

2011/5/10 Michael Niedermayer <git at videolan.org>:
> +#define DITHER_COPY(dst, dstStride, src, srcStride)\

And why not make it a C function, and have a function pointer (eg in
SwsContext) set to it? This would allow specific arch optimizations.

> +                    DITHER_COPY(dstPtr, dstStride[plane], srcPtr2, srcStride[plane]/2)
> +                    DITHER_COPY(dstPtr2, dstStride[plane]/2, srcPtr2, srcStride[plane]/2)

And that would avoid doing those integer divisions by 2 (it's really
signed I guess?) on every line.

Christophe