swscale: error dithering for 16/9/10-bit to 8-bit.

Based on a somewhat similar idea in FFmpeg's swscale copy.

1 files changed, 118 insertions, 17 deletions

diff --git a/libswscale/x86/swscale_template.c b/libswscale/x86/swscale_template.c
index 26cd2742a3..fd6ec3a793 100644
--- a/libswscale/x86/swscale_template.c
+++ b/libswscale/x86/swscale_template.c
@@ -37,8 +37,8 @@
 
 #define YSCALEYUV2YV12X(offset, dest, end, pos) \
     __asm__ volatile(\
-        "movq             "VROUNDER_OFFSET"(%0), %%mm3      \n\t"\
-        "movq                             %%mm3, %%mm4      \n\t"\
+        "movq                  "DITHER16"+0(%0), %%mm3      \n\t"\
+        "movq                  "DITHER16"+8(%0), %%mm4      \n\t"\
         "lea                     " offset "(%0), %%"REG_d"  \n\t"\
         "mov                        (%%"REG_d"), %%"REG_S"  \n\t"\
         ".p2align                             4             \n\t" /* FIXME Unroll? */\
@@ -60,8 +60,8 @@
         MOVNTQ(%%mm3, (%1, %3))\
         "add                                 $8, %3         \n\t"\
         "cmp                                 %2, %3         \n\t"\
-        "movq             "VROUNDER_OFFSET"(%0), %%mm3      \n\t"\
-        "movq                             %%mm3, %%mm4      \n\t"\
+        "movq                  "DITHER16"+0(%0), %%mm3      \n\t"\
+        "movq                  "DITHER16"+8(%0), %%mm4      \n\t"\
         "lea                     " offset "(%0), %%"REG_d"  \n\t"\
         "mov                        (%%"REG_d"), %%"REG_S"  \n\t"\
         "jb                                  1b             \n\t"\
@@ -70,6 +70,42 @@
         : "%"REG_d, "%"REG_S\
     );
 
+#if !COMPILE_TEMPLATE_MMX2
+static av_always_inline void
+dither_8to16(SwsContext *c, const uint8_t *srcDither, int rot)
+{
+    if (rot) {
+        __asm__ volatile("pxor      %%mm0, %%mm0\n\t"
+                         "movq       (%0), %%mm3\n\t"
+                         "movq      %%mm3, %%mm4\n\t"
+                         "psrlq       $24, %%mm3\n\t"
+                         "psllq       $40, %%mm4\n\t"
+                         "por       %%mm4, %%mm3\n\t"
+                         "movq      %%mm3, %%mm4\n\t"
+                         "punpcklbw %%mm0, %%mm3\n\t"
+                         "punpckhbw %%mm0, %%mm4\n\t"
+                         "psraw        $4, %%mm3\n\t"
+                         "psraw        $4, %%mm4\n\t"
+                         "movq      %%mm3, "DITHER16"+0(%1)\n\t"
+                         "movq      %%mm4, "DITHER16"+8(%1)\n\t"
+                         :: "r"(srcDither), "r"(&c->redDither)
+                         );
+    } else {
+        __asm__ volatile("pxor      %%mm0, %%mm0\n\t"
+                         "movq       (%0), %%mm3\n\t"
+                         "movq      %%mm3, %%mm4\n\t"
+                         "punpcklbw %%mm0, %%mm3\n\t"
+                         "punpckhbw %%mm0, %%mm4\n\t"
+                         "psraw        $4, %%mm3\n\t"
+                         "psraw        $4, %%mm4\n\t"
+                         "movq      %%mm3, "DITHER16"+0(%1)\n\t"
+                         "movq      %%mm4, "DITHER16"+8(%1)\n\t"
+                         :: "r"(srcDither), "r"(&c->redDither)
+                         );
+    }
+}
+#endif
+
 static void RENAME(yuv2yuvX)(SwsContext *c, const int16_t *lumFilter,
                              const int16_t **lumSrc, int lumFilterSize,
                              const int16_t *chrFilter, const int16_t **chrUSrc,
@@ -79,12 +115,16 @@ static void RENAME(yuv2yuvX)(SwsContext *c, const int16_t *lumFilter,
 {
     uint8_t *yDest = dest[0], *uDest = dest[1], *vDest = dest[2],
             *aDest = CONFIG_SWSCALE_ALPHA ? dest[3] : NULL;
+    const uint8_t *lumDither = c->lumDither8, *chrDither = c->chrDither8;
 
     if (uDest) {
         x86_reg uv_off = c->uv_offx2 >> 1;
+        dither_8to16(c, chrDither, 0);
         YSCALEYUV2YV12X(CHR_MMX_FILTER_OFFSET, uDest, chrDstW, 0)
+        dither_8to16(c, chrDither, 1);
         YSCALEYUV2YV12X(CHR_MMX_FILTER_OFFSET, vDest - uv_off, chrDstW + uv_off, uv_off)
     }
+    dither_8to16(c, lumDither, 0);
     if (CONFIG_SWSCALE_ALPHA && aDest) {
         YSCALEYUV2YV12X(ALP_MMX_FILTER_OFFSET, aDest, dstW, 0)
     }
@@ -95,10 +135,10 @@ static void RENAME(yuv2yuvX)(SwsContext *c, const int16_t *lumFilter,
 #define YSCALEYUV2YV12X_ACCURATE(offset, dest, end, pos) \
     __asm__ volatile(\
         "lea                     " offset "(%0), %%"REG_d"  \n\t"\
-        "pxor                             %%mm4, %%mm4      \n\t"\
-        "pxor                             %%mm5, %%mm5      \n\t"\
-        "pxor                             %%mm6, %%mm6      \n\t"\
-        "pxor                             %%mm7, %%mm7      \n\t"\
+        "movq                  "DITHER32"+0(%0), %%mm4      \n\t"\
+        "movq                  "DITHER32"+8(%0), %%mm5      \n\t"\
+        "movq                 "DITHER32"+16(%0), %%mm6      \n\t"\
+        "movq                 "DITHER32"+24(%0), %%mm7      \n\t"\
         "mov                        (%%"REG_d"), %%"REG_S"  \n\t"\
         ".p2align                             4             \n\t"\
         "1:                                                 \n\t"\
@@ -142,10 +182,10 @@ static void RENAME(yuv2yuvX)(SwsContext *c, const int16_t *lumFilter,
         "add                                 $8, %3         \n\t"\
         "cmp                                 %2, %3         \n\t"\
         "lea                     " offset "(%0), %%"REG_d"  \n\t"\
-        "pxor                             %%mm4, %%mm4      \n\t"\
-        "pxor                             %%mm5, %%mm5      \n\t"\
-        "pxor                             %%mm6, %%mm6      \n\t"\
-        "pxor                             %%mm7, %%mm7      \n\t"\
+        "movq                  "DITHER32"+0(%0), %%mm4      \n\t"\
+        "movq                  "DITHER32"+8(%0), %%mm5      \n\t"\
+        "movq                 "DITHER32"+16(%0), %%mm6      \n\t"\
+        "movq                 "DITHER32"+24(%0), %%mm7      \n\t"\
         "mov                        (%%"REG_d"), %%"REG_S"  \n\t"\
         "jb                                  1b             \n\t"\
         :: "r" (&c->redDither),\
@@ -153,6 +193,62 @@ static void RENAME(yuv2yuvX)(SwsContext *c, const int16_t *lumFilter,
         : "%"REG_a, "%"REG_d, "%"REG_S\
     );
 
+#if !COMPILE_TEMPLATE_MMX2
+static av_always_inline void
+dither_8to32(SwsContext *c, const uint8_t *srcDither, int rot)
+{
+    if (rot) {
+        __asm__ volatile("pxor      %%mm0, %%mm0\n\t"
+                         "movq       (%0), %%mm4\n\t"
+                         "movq      %%mm4, %%mm5\n\t"
+                         "psrlq       $24, %%mm4\n\t"
+                         "psllq       $40, %%mm5\n\t"
+                         "por       %%mm5, %%mm4\n\t"
+                         "movq      %%mm4, %%mm6\n\t"
+                         "punpcklbw %%mm0, %%mm4\n\t"
+                         "punpckhbw %%mm0, %%mm6\n\t"
+                         "movq      %%mm4, %%mm5\n\t"
+                         "movq      %%mm6, %%mm7\n\t"
+                         "punpcklwd %%mm0, %%mm4\n\t"
+                         "punpckhwd %%mm0, %%mm5\n\t"
+                         "punpcklwd %%mm0, %%mm6\n\t"
+                         "punpckhwd %%mm0, %%mm7\n\t"
+                         "psllw       $12, %%mm4\n\t"
+                         "psllw       $12, %%mm5\n\t"
+                         "psllw       $12, %%mm6\n\t"
+                         "psllw       $12, %%mm7\n\t"
+                         "movq      %%mm3, "DITHER32"+0(%1)\n\t"
+                         "movq      %%mm4, "DITHER32"+8(%1)\n\t"
+                         "movq      %%mm4, "DITHER32"+16(%1)\n\t"
+                         "movq      %%mm4, "DITHER32"+24(%1)\n\t"
+                         :: "r"(srcDither), "r"(&c->redDither)
+                         );
+    } else {
+        __asm__ volatile("pxor      %%mm0, %%mm0\n\t"
+                         "movq       (%0), %%mm4\n\t"
+                         "movq      %%mm4, %%mm6\n\t"
+                         "punpcklbw %%mm0, %%mm4\n\t"
+                         "punpckhbw %%mm0, %%mm6\n\t"
+                         "movq      %%mm4, %%mm5\n\t"
+                         "movq      %%mm6, %%mm7\n\t"
+                         "punpcklwd %%mm0, %%mm4\n\t"
+                         "punpckhwd %%mm0, %%mm5\n\t"
+                         "punpcklwd %%mm0, %%mm6\n\t"
+                         "punpckhwd %%mm0, %%mm7\n\t"
+                         "psllw       $12, %%mm4\n\t"
+                         "psllw       $12, %%mm5\n\t"
+                         "psllw       $12, %%mm6\n\t"
+                         "psllw       $12, %%mm7\n\t"
+                         "movq      %%mm3, "DITHER32"+0(%1)\n\t"
+                         "movq      %%mm4, "DITHER32"+8(%1)\n\t"
+                         "movq      %%mm4, "DITHER32"+16(%1)\n\t"
+                         "movq      %%mm4, "DITHER32"+24(%1)\n\t"
+                         :: "r"(srcDither), "r"(&c->redDither)
+                         );
+    }
+}
+#endif
+
 static void RENAME(yuv2yuvX_ar)(SwsContext *c, const int16_t *lumFilter,
                                 const int16_t **lumSrc, int lumFilterSize,
                                 const int16_t *chrFilter, const int16_t **chrUSrc,
@@ -162,12 +258,16 @@ static void RENAME(yuv2yuvX_ar)(SwsContext *c, const int16_t *lumFilter,
 {
     uint8_t *yDest = dest[0], *uDest = dest[1], *vDest = dest[2],
             *aDest = CONFIG_SWSCALE_ALPHA ? dest[3] : NULL;
+    const uint8_t *lumDither = c->lumDither8, *chrDither = c->chrDither8;
 
     if (uDest) {
         x86_reg uv_off = c->uv_offx2 >> 1;
+        dither_8to32(c, chrDither, 0);
         YSCALEYUV2YV12X_ACCURATE(CHR_MMX_FILTER_OFFSET, uDest, chrDstW, 0)
+        dither_8to32(c, chrDither, 1);
         YSCALEYUV2YV12X_ACCURATE(CHR_MMX_FILTER_OFFSET, vDest - uv_off, chrDstW + uv_off, uv_off)
     }
+    dither_8to32(c, lumDither, 0);
     if (CONFIG_SWSCALE_ALPHA && aDest) {
         YSCALEYUV2YV12X_ACCURATE(ALP_MMX_FILTER_OFFSET, aDest, dstW, 0)
     }
@@ -220,19 +320,20 @@ static void RENAME(yuv2yuv1_ar)(SwsContext *c, const int16_t *lumSrc,
         chrVSrc + chrDstW, alpSrc + dstW
     };
     x86_reg counter[4]= { dstW, chrDstW, chrDstW, dstW };
+    const uint8_t *lumDither = c->lumDither8, *chrDither = c->chrDither8;
 
     while (p--) {
         if (dst[p]) {
+            dither_8to16(c, (p == 2 || p == 3) ? chrDither : lumDither, p == 2);
             __asm__ volatile(
                 "mov %2, %%"REG_a"                    \n\t"
-                "pcmpeqw %%mm7, %%mm7                 \n\t"
-                "psrlw                 $15, %%mm7     \n\t"
-                "psllw                  $6, %%mm7     \n\t"
+                "movq    "DITHER16"+0(%3), %%mm6      \n\t"
+                "movq    "DITHER16"+8(%3), %%mm7      \n\t"
                 ".p2align                4            \n\t" /* FIXME Unroll? */
                 "1:                                   \n\t"
                 "movq  (%0, %%"REG_a", 2), %%mm0      \n\t"
                 "movq 8(%0, %%"REG_a", 2), %%mm1      \n\t"
-                "paddsw             %%mm7, %%mm0      \n\t"
+                "paddsw             %%mm6, %%mm0      \n\t"
                 "paddsw             %%mm7, %%mm1      \n\t"
                 "psraw                 $7, %%mm0      \n\t"
                 "psraw                 $7, %%mm1      \n\t"
@@ -241,7 +342,7 @@ static void RENAME(yuv2yuv1_ar)(SwsContext *c, const int16_t *lumSrc,
                 "add                   $8, %%"REG_a"  \n\t"
                 "jnc                   1b             \n\t"
                 :: "r" (src[p]), "r" (dst[p] + counter[p]),
-                   "g" (-counter[p])
+                   "g" (-counter[p]), "r"(&c->redDither)
                 : "%"REG_a
             );
         }