[FFmpeg-devel] [PATCH] Huffyuv speed tweaks

[Jason Garrett-Glaser]

$subj, faster decoding pixel prediction.

Dark Shikari

Index: libavcodec/huffyuv.c
===================================================================
--- libavcodec/huffyuv.c	(revision 14661)
+++ libavcodec/huffyuv.c	(working copy)
@@ -131,17 +131,23 @@
 static inline int add_left_prediction(uint8_t *dst, uint8_t *src, int
w, int acc){
     int i;

-    for(i=0; i<w-1; i++){
-        acc+= src[i];
-        dst[i]= acc;
-        i++;
-        acc+= src[i];
-        dst[i]= acc;
+    for(i=0; i<(w>>2); i++){
+        acc+= src[0];
+        dst[0]= acc;
+        acc+= src[1];
+        dst[1]= acc;
+        acc+= src[2];
+        dst[2]= acc;
+        acc+= src[3];
+        dst[3]= acc;
+        src+=4;
+        dst+=4;
     }
-
-    for(; i<w; i++){
-        acc+= src[i];
-        dst[i]= acc;
+    for(i<<=2; i<w; i++){
+        acc+= *src;
+        *dst= acc;
+        src++;
+        dst++;
     }

     return acc;
@@ -155,9 +161,12 @@
     lt= *left_top;

     for(i=0; i<w; i++){
-        l= mid_pred(l, src1[i], (l + src1[i] - lt)&0xFF) + diff[i];
-        lt= src1[i];
-        dst[i]= l;
+        l= mid_pred(l, *src1, (l + *src1 - lt)&0xFF) + *diff;
+        lt= *src1;
+        *dst= l;
+        src1++;
+        dst++;
+        diff++;
     }

     *left= l;
@@ -172,13 +181,15 @@
     b= *blue;

     for(i=0; i<w; i++){
-        b+= src[4*i+B];
-        g+= src[4*i+G];
-        r+= src[4*i+R];
+        b+= src[B];
+        g+= src[G];
+        r+= src[R];

-        dst[4*i+B]= b;
-        dst[4*i+G]= g;
-        dst[4*i+R]= r;
+        dst[B]= b;
+        dst[G]= g;
+        dst[R]= r;
+        src+= 4;
+        dst+= 4;
     }

     *red= r;