[FFmpeg-devel] [PATCH] libswscale/swscale_unscaled: fix DITHER_COPY macro
Mateusz
mateuszb at poczta.onet.pl
Tue Sep 5 17:42:06 EEST 2017
W dniu 2017-09-05 o 15:40, Michael Niedermayer pisze:
> On Mon, Sep 04, 2017 at 09:33:34AM +0200, Mateusz wrote:
>> If ffmpeg reduces bit-depth to 8-bit or more, it uses DITHER_COPY macro.
>> The problem is DITHER_COPY macro make images darker (on all planes).
>>
>> In x265 project there is issue #365 which is caused by this DITHER_COPY bug.
>> I think it is time to fix -- there are more and more high bit-depth sources.
>>
>> Please review.
>>
>> libswscale/swscale_unscaled.c | 44 +++++++++++++------------------------------
>> 1 file changed, 13 insertions(+), 31 deletions(-)
>
> please provide a git compatible patch with with commit message as produced
> by git format-patch or git send-email
>
> this mail is not accepted as is by git
> Applying: libswscale/swscale_unscaled: fix DITHER_COPY macro
> error: corrupt patch at line 6
> error: could not build fake ancestor
> Patch failed at 0001 libswscale/swscale_unscaled: fix DITHER_COPY macro
>
> [...]
I've attached the result of git format-patch command.
Sorry for 1 private e-mail (I clicked wrong button).
Mateusz
-------------- next part --------------
From 9b96d612fef46ccec7e148cd7f8e8666b4e7a4cd Mon Sep 17 00:00:00 2001
From: Mateusz <mateuszb at poczta.onet.pl>
Date: Tue, 5 Sep 2017 16:09:28 +0200
Subject: [PATCH] fix DITHER_COPY macro to avoid make images darker
---
libswscale/swscale_unscaled.c | 44 +++++++++++++------------------------------
1 file changed, 13 insertions(+), 31 deletions(-)
diff --git a/libswscale/swscale_unscaled.c b/libswscale/swscale_unscaled.c
index ef36aec..3b7a5a9 100644
--- a/libswscale/swscale_unscaled.c
+++ b/libswscale/swscale_unscaled.c
@@ -110,24 +110,6 @@ DECLARE_ALIGNED(8, static const uint8_t, dithers)[8][8][8]={
{ 112, 16,104, 8,118, 22,110, 14,},
}};
-static const uint16_t dither_scale[15][16]={
-{ 2, 3, 3, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,},
-{ 2, 3, 7, 7, 13, 13, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25,},
-{ 3, 3, 4, 15, 15, 29, 57, 57, 57, 113, 113, 113, 113, 113, 113, 113,},
-{ 3, 4, 4, 5, 31, 31, 61, 121, 241, 241, 241, 241, 481, 481, 481, 481,},
-{ 3, 4, 5, 5, 6, 63, 63, 125, 249, 497, 993, 993, 993, 993, 993, 1985,},
-{ 3, 5, 6, 6, 6, 7, 127, 127, 253, 505, 1009, 2017, 4033, 4033, 4033, 4033,},
-{ 3, 5, 6, 7, 7, 7, 8, 255, 255, 509, 1017, 2033, 4065, 8129,16257,16257,},
-{ 3, 5, 6, 8, 8, 8, 8, 9, 511, 511, 1021, 2041, 4081, 8161,16321,32641,},
-{ 3, 5, 7, 8, 9, 9, 9, 9, 10, 1023, 1023, 2045, 4089, 8177,16353,32705,},
-{ 3, 5, 7, 8, 10, 10, 10, 10, 10, 11, 2047, 2047, 4093, 8185,16369,32737,},
-{ 3, 5, 7, 8, 10, 11, 11, 11, 11, 11, 12, 4095, 4095, 8189,16377,32753,},
-{ 3, 5, 7, 9, 10, 12, 12, 12, 12, 12, 12, 13, 8191, 8191,16381,32761,},
-{ 3, 5, 7, 9, 10, 12, 13, 13, 13, 13, 13, 13, 14,16383,16383,32765,},
-{ 3, 5, 7, 9, 10, 12, 14, 14, 14, 14, 14, 14, 14, 15,32767,32767,},
-{ 3, 5, 7, 9, 11, 12, 14, 15, 15, 15, 15, 15, 15, 15, 16,65535,},
-};
-
static void fillPlane(uint8_t *plane, int stride, int width, int height, int y,
uint8_t val)
@@ -1502,22 +1484,22 @@ static int packedCopyWrapper(SwsContext *c, const uint8_t *src[],
}
#define DITHER_COPY(dst, dstStride, src, srcStride, bswap, dbswap)\
- uint16_t scale= dither_scale[dst_depth-1][src_depth-1];\
- int shift= src_depth-dst_depth + dither_scale[src_depth-2][dst_depth-1];\
+ unsigned shift= src_depth-dst_depth, tmp;\
for (i = 0; i < height; i++) {\
- const uint8_t *dither= dithers[src_depth-9][i&7];\
+ const uint8_t *dither= dithers[shift-1][i&7];\
for (j = 0; j < length-7; j+=8){\
- dst[j+0] = dbswap((bswap(src[j+0]) + dither[0])*scale>>shift);\
- dst[j+1] = dbswap((bswap(src[j+1]) + dither[1])*scale>>shift);\
- dst[j+2] = dbswap((bswap(src[j+2]) + dither[2])*scale>>shift);\
- dst[j+3] = dbswap((bswap(src[j+3]) + dither[3])*scale>>shift);\
- dst[j+4] = dbswap((bswap(src[j+4]) + dither[4])*scale>>shift);\
- dst[j+5] = dbswap((bswap(src[j+5]) + dither[5])*scale>>shift);\
- dst[j+6] = dbswap((bswap(src[j+6]) + dither[6])*scale>>shift);\
- dst[j+7] = dbswap((bswap(src[j+7]) + dither[7])*scale>>shift);\
+ tmp = (bswap(src[j+0]) + dither[0])>>shift; dst[j+0] = dbswap(tmp - (tmp>>dst_depth));\
+ tmp = (bswap(src[j+1]) + dither[1])>>shift; dst[j+1] = dbswap(tmp - (tmp>>dst_depth));\
+ tmp = (bswap(src[j+2]) + dither[2])>>shift; dst[j+2] = dbswap(tmp - (tmp>>dst_depth));\
+ tmp = (bswap(src[j+3]) + dither[3])>>shift; dst[j+3] = dbswap(tmp - (tmp>>dst_depth));\
+ tmp = (bswap(src[j+4]) + dither[4])>>shift; dst[j+4] = dbswap(tmp - (tmp>>dst_depth));\
+ tmp = (bswap(src[j+5]) + dither[5])>>shift; dst[j+5] = dbswap(tmp - (tmp>>dst_depth));\
+ tmp = (bswap(src[j+6]) + dither[6])>>shift; dst[j+6] = dbswap(tmp - (tmp>>dst_depth));\
+ tmp = (bswap(src[j+7]) + dither[7])>>shift; dst[j+7] = dbswap(tmp - (tmp>>dst_depth));\
+ }\
+ for (; j < length; j++){\
+ tmp = (bswap(src[j]) + dither[j&7])>>shift; dst[j] = dbswap(tmp - (tmp>>dst_depth));\
}\
- for (; j < length; j++)\
- dst[j] = dbswap((bswap(src[j]) + dither[j&7])*scale>>shift);\
dst += dstStride;\
src += srcStride;\
}
--
2.7.4
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