dirac: add Comments and references to the standard

[ffmpeg] / libavcodec / rv34dsp.c

diff --git a/libavcodec/rv34dsp.c b/libavcodec/rv34dsp.c
index e2251773af0820b9d9ac98fc23869c6b526b3b5e..ac14ed9ab1654cf4f07b861d432e5115be9b3a78 100644 (file)
--- a/libavcodec/rv34dsp.c
+++ b/libavcodec/rv34dsp.c
@@ -26,6 +26,7 @@
  */
 #include "dsputil.h"
 #include "rv34dsp.h"
+#include "libavutil/common.h"
 
 /**
  * @name RV30/40 inverse transform functions
@@ -53,9 +54,8 @@ static av_always_inline void rv34_row_transform(int temp[16], DCTELEM *block)
  * Real Video 3.0/4.0 inverse transform + sample reconstruction
  * Code is almost the same as in SVQ3, only scaling is different.
  */
-static void rv34_idct_add_c(uint8_t *dst, int stride, DCTELEM *block){
+static void rv34_idct_add_c(uint8_t *dst, ptrdiff_t stride, DCTELEM *block){
     int      temp[16];
-    uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
     int      i;
 
     rv34_row_transform(temp, block);
@@ -67,10 +67,10 @@ static void rv34_idct_add_c(uint8_t *dst, int stride, DCTELEM *block){
         const int z2 =  7* temp[4*1+i] - 17*temp[4*3+i];
         const int z3 = 17* temp[4*1+i] +  7*temp[4*3+i];
 
-        dst[0] = cm[ dst[0] + ( (z0 + z3) >> 10 ) ];
-        dst[1] = cm[ dst[1] + ( (z1 + z2) >> 10 ) ];
-        dst[2] = cm[ dst[2] + ( (z1 - z2) >> 10 ) ];
-        dst[3] = cm[ dst[3] + ( (z0 - z3) >> 10 ) ];
+        dst[0] = av_clip_uint8( dst[0] + ( (z0 + z3) >> 10 ) );
+        dst[1] = av_clip_uint8( dst[1] + ( (z1 + z2) >> 10 ) );
+        dst[2] = av_clip_uint8( dst[2] + ( (z1 - z2) >> 10 ) );
+        dst[3] = av_clip_uint8( dst[3] + ( (z0 - z3) >> 10 ) );
 
         dst  += stride;
     }
@@ -89,29 +89,27 @@ static void rv34_inv_transform_noround_c(DCTELEM *block){
     rv34_row_transform(temp, block);
 
     for(i = 0; i < 4; i++){
-        const int z0 = 13*(temp[4*0+i] +    temp[4*2+i]);
-        const int z1 = 13*(temp[4*0+i] -    temp[4*2+i]);
-        const int z2 =  7* temp[4*1+i] - 17*temp[4*3+i];
-        const int z3 = 17* temp[4*1+i] +  7*temp[4*3+i];
-
-        block[i*4+0] = ((z0 + z3) * 3) >> 11;
-        block[i*4+1] = ((z1 + z2) * 3) >> 11;
-        block[i*4+2] = ((z1 - z2) * 3) >> 11;
-        block[i*4+3] = ((z0 - z3) * 3) >> 11;
+        const int z0 = 39*(temp[4*0+i] +    temp[4*2+i]);
+        const int z1 = 39*(temp[4*0+i] -    temp[4*2+i]);
+        const int z2 = 21* temp[4*1+i] - 51*temp[4*3+i];
+        const int z3 = 51* temp[4*1+i] + 21*temp[4*3+i];
+
+        block[i*4+0] = (z0 + z3) >> 11;
+        block[i*4+1] = (z1 + z2) >> 11;
+        block[i*4+2] = (z1 - z2) >> 11;
+        block[i*4+3] = (z0 - z3) >> 11;
     }
 }
 
-static void rv34_idct_dc_add_c(uint8_t *dst, int stride, int dc)
+static void rv34_idct_dc_add_c(uint8_t *dst, ptrdiff_t stride, int dc)
 {
-    const uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
     int i, j;
 
-    cm += (13*13*dc + 0x200) >> 10;
-
+    dc = (13*13*dc + 0x200) >> 10;
     for (i = 0; i < 4; i++)
     {
         for (j = 0; j < 4; j++)
-            dst[j] = cm[ dst[j] ];
+            dst[j] = av_clip_uint8( dst[j] + dc );
 
         dst += stride;
     }