Faster checks in reverse_dc_prediction.

Patch by Dark Shikari

Originally committed as revision 20750 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/vp3.c

@@ -1233,7 +1233,6 @@ static int unpack_dct_coeffs(Vp3DecodeContext *s, GetBitContext *gb)
  */
 #define COMPATIBLE_FRAME(x) \
   (compatible_frame[s->all_fragments[x].coding_method] == current_frame_type)
-#define FRAME_CODED(x) (s->all_fragments[x].coding_method != MODE_COPY)
 #define DC_COEFF(u) (s->coeffs[u].index ? 0 : s->coeffs[u].coeff) //FIXME do somethin to simplify this
 
 static void reverse_dc_prediction(Vp3DecodeContext *s,
@@ -1290,7 +1289,7 @@ static void reverse_dc_prediction(Vp3DecodeContext *s,
      * from other INTRA blocks. There are 2 golden frame coding types;
      * blocks encoding in these modes can only predict from other blocks
      * that were encoded with these 1 of these 2 modes. */
-    static const unsigned char compatible_frame[8] = {
+    static const unsigned char compatible_frame[9] = {
         1,    /* MODE_INTER_NO_MV */
         0,    /* MODE_INTRA */
         1,    /* MODE_INTER_PLUS_MV */
@@ -1298,7 +1297,8 @@ static void reverse_dc_prediction(Vp3DecodeContext *s,
         1,    /* MODE_INTER_PRIOR_MV */
         2,    /* MODE_USING_GOLDEN */
         2,    /* MODE_GOLDEN_MV */
-        1     /* MODE_INTER_FOUR_MV */
+        1,    /* MODE_INTER_FOUR_MV */
+        3     /* MODE_COPY */
     };
     int current_frame_type;
 
@@ -1326,24 +1326,24 @@ static void reverse_dc_prediction(Vp3DecodeContext *s,
                 if(x){
                     l= i-1;
                     vl = DC_COEFF(l);
-                    if(FRAME_CODED(l) && COMPATIBLE_FRAME(l))
+                    if(COMPATIBLE_FRAME(l))
                         transform |= PL;
                 }
                 if(y){
                     u= i-fragment_width;
                     vu = DC_COEFF(u);
-                    if(FRAME_CODED(u) && COMPATIBLE_FRAME(u))
+                    if(COMPATIBLE_FRAME(u))
                         transform |= PU;
                     if(x){
                         ul= i-fragment_width-1;
                         vul = DC_COEFF(ul);
-                        if(FRAME_CODED(ul) && COMPATIBLE_FRAME(ul))
+                        if(COMPATIBLE_FRAME(ul))
                             transform |= PUL;
                     }
                     if(x + 1 < fragment_width){
                         ur= i-fragment_width+1;
                         vur = DC_COEFF(ur);
-                        if(FRAME_CODED(ur) && COMPATIBLE_FRAME(ur))
+                        if(COMPATIBLE_FRAME(ur))
                             transform |= PUR;
                     }
                 }