1. ffmpeg
  2. Commit 0f583e6cc55dfea865b6b3c9b4ac653455f37ec2
Browse code

vf_hqdn3d: reduce intermediate precision

11% faster on penryn, 7% on sandybridge, 5% on bulldozer
Negligible change to output.

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>

Loren Merritt authored on 2012/07/27 07:51:15
Showing 1 changed files
libavfilter/vf_hqdn3d.c
History View file @ 0f583e6
... ... 
@@ -33,32 +33,32 @@
33 33 
 #include "video.h"
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 typedef struct {
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-    int coefs[4][512*16];
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-    uint32_t *line;
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+    int16_t coefs[4][512*16];
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+    uint16_t *line;
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     uint16_t *frame_prev[3];
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     int hsub, vsub;
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 } HQDN3DContext;
41 41
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-static inline uint32_t lowpass(unsigned int prev, unsigned int cur, int *coef)
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+static inline uint32_t lowpass(int prev, int cur, int16_t *coef)
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 {
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-    int dmul = prev-cur;
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-    unsigned int d = (dmul+0x10007FF)>>12; // 0x1000 to convert to unsigned, 7FF for rounding
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+    int d = (prev-cur)>>4;
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     return cur + coef[d];
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 }
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 static void denoise_temporal(uint8_t *src, uint8_t *dst,
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                              uint16_t *frame_ant,
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                              int w, int h, int sstride, int dstride,
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-                             int *temporal)
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+                             int16_t *temporal)
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 {
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     long x, y;
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     uint32_t tmp;
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+    temporal += 0x1000;
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+
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     for (y = 0; y < h; y++) {
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         for (x = 0; x < w; x++) {
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-            tmp = lowpass(frame_ant[x]<<8, src[x]<<16, temporal);
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-            frame_ant[x] = (tmp+0x7F)>>8;
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-            dst[x] = (tmp+0x7FFF)>>16;
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+            frame_ant[x] = tmp = lowpass(frame_ant[x], src[x]<<8, temporal);
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+            dst[x] = (tmp+0x7F)>>8;
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         }
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         src += sstride;
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         dst += dstride;
... ... 
@@ -67,47 +67,47 @@ static void denoise_temporal(uint8_t *src, uint8_t *dst,
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 }
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 static void denoise_spatial(uint8_t *src, uint8_t *dst,
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-                            uint32_t *line_ant, uint16_t *frame_ant,
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+                            uint16_t *line_ant, uint16_t *frame_ant,
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                             int w, int h, int sstride, int dstride,
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-                            int *spatial, int *temporal)
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+                            int16_t *spatial, int16_t *temporal)
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 {
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     long x, y;
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     uint32_t pixel_ant;
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     uint32_t tmp;
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+    spatial  += 0x1000;
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+    temporal += 0x1000;
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+
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     /* First line has no top neighbor. Only left one for each tmp and
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      * last frame */
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-    pixel_ant = src[0]<<16;
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+    pixel_ant = src[0]<<8;
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     for (x = 0; x < w; x++) {
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-        line_ant[x] = tmp = pixel_ant = lowpass(pixel_ant, src[x]<<16, spatial);
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-        tmp = lowpass(frame_ant[x]<<8, tmp, temporal);
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-        frame_ant[x] = (tmp+0x7F)>>8;
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-        dst[x] = (tmp+0x7FFF)>>16;
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+        line_ant[x] = tmp = pixel_ant = lowpass(pixel_ant, src[x]<<8, spatial);
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+        frame_ant[x] = tmp = lowpass(frame_ant[x], tmp, temporal);
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+        dst[x] = (tmp+0x7F)>>8;
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     }
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     for (y = 1; y < h; y++) {
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         src += sstride;
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         dst += dstride;
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         frame_ant += w;
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-        pixel_ant = src[0]<<16;
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+        pixel_ant = src[0]<<8;
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         for (x = 0; x < w-1; x++) {
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             line_ant[x] = tmp = lowpass(line_ant[x], pixel_ant, spatial);
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-            pixel_ant = lowpass(pixel_ant, src[x+1]<<16, spatial);
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-            tmp = lowpass(frame_ant[x]<<8, tmp, temporal);
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-            frame_ant[x] = (tmp+0x7F)>>8;
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-            dst[x] = (tmp+0x7FFF)>>16;
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+            pixel_ant = lowpass(pixel_ant, src[x+1]<<8, spatial);
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+            frame_ant[x] = tmp = lowpass(frame_ant[x], tmp, temporal);
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+            dst[x] = (tmp+0x7F)>>8;
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         }
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         line_ant[x] = tmp = lowpass(line_ant[x], pixel_ant, spatial);
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-        tmp = lowpass(frame_ant[x]<<8, tmp, temporal);
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-        frame_ant[x] = (tmp+0x7F)>>8;
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-        dst[x] = (tmp+0x7FFF)>>16;
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+        frame_ant[x] = tmp = lowpass(frame_ant[x], tmp, temporal);
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+        dst[x] = (tmp+0x7F)>>8;
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     }
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 }
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 static void denoise(uint8_t *src, uint8_t *dst,
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-                    uint32_t *line_ant, uint16_t **frame_ant_ptr,
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+                    uint16_t *line_ant, uint16_t **frame_ant_ptr,
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                     int w, int h, int sstride, int dstride,
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-                    int *spatial, int *temporal)
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+                    int16_t *spatial, int16_t *temporal)
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 {
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     long x, y;
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     uint16_t *frame_ant = *frame_ant_ptr;
... ... 
@@ -129,16 +129,18 @@ static void denoise(uint8_t *src, uint8_t *dst,
129 129 
                          w, h, sstride, dstride, temporal);
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 }
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-static void precalc_coefs(int *ct, double dist25)
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+static void precalc_coefs(int16_t *ct, double dist25)
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 {
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     int i;
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     double gamma, simil, C;
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-    gamma = log(0.25) / log(1.0 - dist25/255.0 - 0.00001);
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+    gamma = log(0.25) / log(1.0 - FFMIN(dist25,252.0)/255.0 - 0.00001);
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     for (i = -255*16; i <= 255*16; i++) {
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-        simil = 1.0 - FFABS(i) / (16*255.0);
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-        C = pow(simil, gamma) * 65536.0 * i / 16.0;
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+        // lowpass() truncates (not rounds) the diff, so +15/32 for the midpoint of the bin.
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+        double f = (i + 15.0/32.0) / 16.0;
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+        simil = 1.0 - FFABS(f) / 255.0;
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+        C = pow(simil, gamma) * 256.0 * f;
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         ct[16*256+i] = lrint(C);
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     }
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