swscale: use dithering in DITHER_COPY only if not set -sws_dither none

This patch uses dithering in DITHER_COPY macro only if
it was not used option '-sws_dither none'.
With option '-sws_dither none' it uses downshift.

For human eye dithering is OK, for video codecs not necessarily.
If user don't want to use dithering, we should respect that.

Signed-off-by: Mateusz Brzostek <mateuszb@poczta.onet.pl>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Mateusz 2017-10-24 10:02:17 +02:00 committed by Michael Niedermayer
parent 736a48901f
commit 50ce296026

View File

@ -1485,7 +1485,25 @@ static int packedCopyWrapper(SwsContext *c, const uint8_t *src[],
#define DITHER_COPY(dst, dstStride, src, srcStride, bswap, dbswap)\
unsigned shift= src_depth-dst_depth, tmp;\
if (shiftonly) {\
if (c->dither == SWS_DITHER_NONE) {\
for (i = 0; i < height; i++) {\
for (j = 0; j < length-7; j+=8) {\
dst[j+0] = dbswap(bswap(src[j+0])>>shift);\
dst[j+1] = dbswap(bswap(src[j+1])>>shift);\
dst[j+2] = dbswap(bswap(src[j+2])>>shift);\
dst[j+3] = dbswap(bswap(src[j+3])>>shift);\
dst[j+4] = dbswap(bswap(src[j+4])>>shift);\
dst[j+5] = dbswap(bswap(src[j+5])>>shift);\
dst[j+6] = dbswap(bswap(src[j+6])>>shift);\
dst[j+7] = dbswap(bswap(src[j+7])>>shift);\
}\
for (; j < length; j++) {\
dst[j] = dbswap(bswap(src[j])>>shift);\
}\
dst += dstStride;\
src += srcStride;\
}\
} else if (shiftonly) {\
for (i = 0; i < height; i++) {\
const uint8_t *dither= dithers[shift-1][i&7];\
for (j = 0; j < length-7; j+=8) {\