avoid double copying of left border in luma prediction

Originally committed as revision 5752 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/cavs.c

@@ -82,7 +82,8 @@ typedef struct {
     /** intra prediction is done with un-deblocked samples
      they are saved here before deblocking the MB  */
     uint8_t *top_border_y, *top_border_u, *top_border_v;
-    uint8_t left_border_y[16], left_border_u[10], left_border_v[10];
+    uint8_t left_border_y[26], left_border_u[10], left_border_v[10];
+    uint8_t intern_border_y[26];
     uint8_t topleft_border_y, topleft_border_u, topleft_border_v;
 
     void (*intra_pred_l[8])(uint8_t *d,uint8_t *top,uint8_t *left,int stride);
@@ -151,8 +152,8 @@ static void filter_mb(AVSContext *h, enum mb_t mb_type) {
     memcpy(&h->top_border_u[h->mbx*10+1], h->cu +  7* h->c_stride,8);
     memcpy(&h->top_border_v[h->mbx*10+1], h->cv +  7* h->c_stride,8);
     for(i=0;i<8;i++) {
-        h->left_border_y[i*2+0] = *(h->cy + 15 + (i*2+0)*h->l_stride);
-        h->left_border_y[i*2+1] = *(h->cy + 15 + (i*2+1)*h->l_stride);
+        h->left_border_y[i*2+1] = *(h->cy + 15 + (i*2+0)*h->l_stride);
+        h->left_border_y[i*2+2] = *(h->cy + 15 + (i*2+1)*h->l_stride);
         h->left_border_u[i+1] = *(h->cu + 7 + i*h->c_stride);
         h->left_border_v[i+1] = *(h->cv + 7 + i*h->c_stride);
     }
@@ -211,25 +212,26 @@ static void filter_mb(AVSContext *h, enum mb_t mb_type) {
  ****************************************************************************/
 
 static inline void load_intra_pred_luma(AVSContext *h, uint8_t *top,
-                                        uint8_t *left, int block) {
+                                        uint8_t **left, int block) {
     int i;
 
     switch(block) {
     case 0:
-        memcpy(&left[1],h->left_border_y,16);
-        left[0] = left[1];
-        left[17] = left[16];
+        *left = h->left_border_y;
+        h->left_border_y[0] = h->left_border_y[1];
+        memset(&h->left_border_y[17],h->left_border_y[16],9);
         memcpy(&top[1],&h->top_border_y[h->mbx*16],16);
         top[17] = top[16];
         top[0] = top[1];
         if((h->flags & A_AVAIL) && (h->flags & B_AVAIL))
-            left[0] = top[0] = h->topleft_border_y;
+            h->left_border_y[0] = top[0] = h->topleft_border_y;
         break;
     case 1:
+        *left = h->intern_border_y;
         for(i=0;i<8;i++)
-            left[i+1] = *(h->cy + 7 + i*h->l_stride);
-        memset(&left[9],left[8],9);
-        left[0] = left[1];
+            h->intern_border_y[i+1] = *(h->cy + 7 + i*h->l_stride);
+        memset(&h->intern_border_y[9],h->intern_border_y[8],9);
+        h->intern_border_y[0] = h->intern_border_y[1];
         memcpy(&top[1],&h->top_border_y[h->mbx*16+8],8);
         if(h->flags & C_AVAIL)
             memcpy(&top[9],&h->top_border_y[(h->mbx + 1)*16],8);
@@ -238,22 +240,21 @@ static inline void load_intra_pred_luma(AVSContext *h, uint8_t *top,
         top[17] = top[16];
         top[0] = top[1];
         if(h->flags & B_AVAIL)
-            left[0] = top[0] = h->top_border_y[h->mbx*16+7];
+            h->intern_border_y[0] = top[0] = h->top_border_y[h->mbx*16+7];
         break;
     case 2:
-        memcpy(&left[1],&h->left_border_y[8],8);
-        memset(&left[9],left[8],9);
+        *left = &h->left_border_y[8];
         memcpy(&top[1],h->cy + 7*h->l_stride,16);
         top[17] = top[16];
-        left[0] = h->left_border_y[7];
         top[0] = top[1];
         if(h->flags & A_AVAIL)
-            top[0] = left[0];
+            top[0] = h->left_border_y[8];
         break;
     case 3:
-        for(i=0;i<9;i++)
-            left[i] = *(h->cy + 7 + (i+7)*h->l_stride);
-        memset(&left[9],left[8],9);
+        *left = &h->intern_border_y[8];
+        for(i=0;i<8;i++)
+            h->intern_border_y[i+9] = *(h->cy + 7 + (i+8)*h->l_stride);
+        memset(&h->intern_border_y[17],h->intern_border_y[16],9);
         memcpy(&top[0],h->cy + 7 + 7*h->l_stride,9);
         memset(&top[9],top[8],9);
         break;
@@ -816,7 +817,7 @@ static int decode_mb_i(AVSContext *h, int cbp_code) {
     GetBitContext *gb = &h->s.gb;
     int block, pred_mode_uv;
     uint8_t top[18];
-    uint8_t left[18];
+    uint8_t *left = NULL;
     uint8_t *d;
 
     init_mb(h);
@@ -875,7 +876,7 @@ static int decode_mb_i(AVSContext *h, int cbp_code) {
     /* luma intra prediction interleaved with residual decode/transform/add */
     for(block=0;block<4;block++) {
         d = h->cy + h->luma_scan[block];
-        load_intra_pred_luma(h, top, left, block);
+        load_intra_pred_luma(h, top, &left, block);
         h->intra_pred_l[h->pred_mode_Y[scan3x3[block]]]
             (d, top, left, h->l_stride);
         if(h->cbp & (1<<block))