aacenc: Split paths in the scalefactor selection trellis into a 2-D array.

Originally committed as revision 19947 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/aaccoder.c

@@ -468,26 +468,28 @@ static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
                                        const float lambda)
 {
     int q, w, w2, g, start = 0;
-    int i;
+    int i, j;
     int idx;
-    TrellisPath paths[256*121];
+    TrellisPath paths[121][256];
     int bandaddr[121];
     int minq;
     float mincost;
 
     for (i = 0; i < 256; i++) {
-        paths[i].cost    = 0.0f;
-        paths[i].prev    = -1;
-        paths[i].min_val = i;
-        paths[i].max_val = i;
-    }
-    for (i = 256; i < 256*121; i++) {
-        paths[i].cost    = INFINITY;
-        paths[i].prev    = -2;
-        paths[i].min_val = INT_MAX;
-        paths[i].max_val = 0;
-    }
-    idx = 256;
+        paths[0][i].cost    = 0.0f;
+        paths[0][i].prev    = -1;
+        paths[0][i].min_val = i;
+        paths[0][i].max_val = i;
+    }
+    for (j = 1; j < 121; j++) {
+        for (i = 0; i < 256; i++) {
+            paths[j][i].cost    = INFINITY;
+            paths[j][i].prev    = -2;
+            paths[j][i].min_val = INT_MAX;
+            paths[j][i].max_val = 0;
+        }
+    }
+    idx = 1;
     abs_pow34_v(s->scoefs, sce->coeffs, 1024);
     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
         start = w*128;
@@ -496,7 +498,7 @@ static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
             float qmin, qmax;
             int nz = 0;
 
-            bandaddr[idx >> 8] = w * 16 + g;
+            bandaddr[idx] = w * 16 + g;
             qmin = INT_MAX;
             qmax = 0.0f;
             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
@@ -539,63 +541,64 @@ static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, 256); i++) {
                         float cost;
                         int minv, maxv;
-                        if (isinf(paths[idx - 256 + i].cost))
+                        if (isinf(paths[idx - 1][i].cost))
                             continue;
-                        cost = paths[idx - 256 + i].cost + dist
+                        cost = paths[idx - 1][i].cost + dist
                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
-                        minv = FFMIN(paths[idx - 256 + i].min_val, q);
-                        maxv = FFMAX(paths[idx - 256 + i].max_val, q);
-                        if (cost < paths[idx + q].cost && maxv-minv < SCALE_MAX_DIFF) {
-                            paths[idx + q].cost    = cost;
-                            paths[idx + q].prev    = idx - 256 + i;
-                            paths[idx + q].min_val = minv;
-                            paths[idx + q].max_val = maxv;
+                        minv = FFMIN(paths[idx - 1][i].min_val, q);
+                        maxv = FFMAX(paths[idx - 1][i].max_val, q);
+                        if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
+                            paths[idx][q].cost    = cost;
+                            paths[idx][q].prev    = i;
+                            paths[idx][q].min_val = minv;
+                            paths[idx][q].max_val = maxv;
                         }
                     }
                 }
             } else {
                 for (q = 0; q < 256; q++) {
-                    if (!isinf(paths[idx - 256 + q].cost)) {
-                        paths[idx + q].cost = paths[idx - 256 + q].cost + 1;
-                        paths[idx + q].prev = idx - 256 + q;
-                        paths[idx + q].min_val = FFMIN(paths[idx - 256 + q].min_val, q);
-                        paths[idx + q].max_val = FFMAX(paths[idx - 256 + q].max_val, q);
+                    if (!isinf(paths[idx - 1][q].cost)) {
+                        paths[idx][q].cost = paths[idx - 1][q].cost + 1;
+                        paths[idx][q].prev = q;
+                        paths[idx][q].min_val = FFMIN(paths[idx - 1][q].min_val, q);
+                        paths[idx][q].max_val = FFMAX(paths[idx - 1][q].max_val, q);
                         continue;
                     }
                     for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, 256); i++) {
                         float cost;
                         int minv, maxv;
-                        if (isinf(paths[idx - 256 + i].cost))
+                        if (isinf(paths[idx - 1][i].cost))
                             continue;
-                        cost = paths[idx - 256 + i].cost + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
-                        minv = FFMIN(paths[idx - 256 + i].min_val, q);
-                        maxv = FFMAX(paths[idx - 256 + i].max_val, q);
-                        if (cost < paths[idx + q].cost && maxv-minv < SCALE_MAX_DIFF) {
-                            paths[idx + q].cost    = cost;
-                            paths[idx + q].prev    = idx - 256 + i;
-                            paths[idx + q].min_val = minv;
-                            paths[idx + q].max_val = maxv;
+                        cost = paths[idx - 1][i].cost + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
+                        minv = FFMIN(paths[idx - 1][i].min_val, q);
+                        maxv = FFMAX(paths[idx - 1][i].max_val, q);
+                        if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
+                            paths[idx][q].cost    = cost;
+                            paths[idx][q].prev    = i;
+                            paths[idx][q].min_val = minv;
+                            paths[idx][q].max_val = maxv;
                         }
                     }
                 }
             }
             sce->zeroes[w*16+g] = !nz;
             start += sce->ics.swb_sizes[g];
-            idx   += 256;
+            idx++;
         }
     }
-    idx -= 256;
-    mincost = paths[idx].cost;
-    minq    = idx;
+    idx--;
+    mincost = paths[idx][0].cost;
+    minq    = 0;
     for (i = 1; i < 256; i++) {
-        if (paths[idx + i].cost < mincost) {
-            mincost = paths[idx + i].cost;
-            minq = idx + i;
+        if (paths[idx][i].cost < mincost) {
+            mincost = paths[idx][i].cost;
+            minq = i;
         }
     }
-    while (minq >= 256) {
-        sce->sf_idx[bandaddr[minq>>8]] = minq & 0xFF;
-        minq = paths[minq].prev;
+    while (idx) {
+        sce->sf_idx[bandaddr[idx]] = minq;
+        minq = paths[idx][minq].prev;
+        idx--;
     }
     //set the same quantizers inside window groups
     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])