[FFmpeg-devel] [PATCH] Add DPX decoder rev-16

[Reimar Döffinger]

On Wed, Jun 03, 2009 at 06:07:59PM +0200, Jimmy Christensen wrote:
> +            *dst++ = (((rgbBuffer & 0xFFC00000) >> 16) + ((rgbBuffer & 0xFFC00000) >> 26));

The second &-masking is useless.

> +            *dst++ = (((rgbBuffer & 0x003FF000) >> 6) + ((rgbBuffer & 0x003FF000) >> 16));
> +            *dst++ = (((rgbBuffer & 0x00000FFC) << 4) + ((rgbBuffer & 0x00000FFC) >> 6));

having the & 0x... twice is ugly.

Also I think it would be more readable as e.g.
dst[0] = rgbBuffer >> 16;
dst[1] = rgbBuffer >>  6;
dst[2] = rgbBuffer <<  4;
for (i = 0; i < 3; i++) {
    // mask away invalid bits
    dst[i] &= 0xFFC0;
    // correctly expand to 16 bits
    dst[i] += dst[i] >> 10;
}

Note that if you are pedantic, in that loop
dst[i] = (dst[i] & 0xFFC0) + (dst[i] >> 10);
might be faster since it removes a data dependency.