H.264: switch to x264-style tracking of luma/chroma DC NNZ

Useful so that we don't have to run the hierarchical DC iDCT if there aren't
any coefficients.  Opens up some future opportunities for optimization as well.

Originally committed as revision 26337 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 5 insertions, 5 deletions

diff --git a/libavcodec/h264_cavlc.c b/libavcodec/h264_cavlc.c
index 426a285570..b8bc45058c 100644
--- a/libavcodec/h264_cavlc.c
+++ b/libavcodec/h264_cavlc.c
@@ -371,7 +371,7 @@ static int decode_residual(H264Context *h, GetBitContext *gb, DCTELEM *block, in
 
     //FIXME put trailing_onex into the context
 
-    if(n == CHROMA_DC_BLOCK_INDEX){
+    if(n >= CHROMA_DC_BLOCK_INDEX){
         coeff_token= get_vlc2(gb, chroma_dc_coeff_token_vlc.table, CHROMA_DC_COEFF_TOKEN_VLC_BITS, 1);
         total_coeff= coeff_token>>2;
     }else{
@@ -383,9 +383,9 @@ static int decode_residual(H264Context *h, GetBitContext *gb, DCTELEM *block, in
             total_coeff= pred_non_zero_count(h, n);
             coeff_token= get_vlc2(gb, coeff_token_vlc[ coeff_token_table_index[total_coeff] ].table, COEFF_TOKEN_VLC_BITS, 2);
             total_coeff= coeff_token>>2;
-            h->non_zero_count_cache[ scan8[n] ]= total_coeff;
         }
     }
+    h->non_zero_count_cache[ scan8[n] ]= total_coeff;
 
     //FIXME set last_non_zero?
 
@@ -482,14 +482,14 @@ static int decode_residual(H264Context *h, GetBitContext *gb, DCTELEM *block, in
     if(total_coeff == max_coeff)
         zeros_left=0;
     else{
-        if(n == CHROMA_DC_BLOCK_INDEX)
+        if(n >= CHROMA_DC_BLOCK_INDEX)
             zeros_left= get_vlc2(gb, (chroma_dc_total_zeros_vlc-1)[ total_coeff ].table, CHROMA_DC_TOTAL_ZEROS_VLC_BITS, 1);
         else
             zeros_left= get_vlc2(gb, (total_zeros_vlc-1)[ total_coeff ].table, TOTAL_ZEROS_VLC_BITS, 1);
     }
 
     scantable += zeros_left + total_coeff - 1;
-    if(n > 24){
+    if(n >= LUMA_DC_BLOCK_INDEX){
         block[*scantable] = level[0];
         for(i=1;i<total_coeff && zeros_left > 0;i++) {
             if(zeros_left < 7)
@@ -988,7 +988,7 @@ decode_intra_mb:
 
         if(cbp&0x30){
             for(chroma_idx=0; chroma_idx<2; chroma_idx++)
-                if( decode_residual(h, gb, h->mb + 256 + 16*4*chroma_idx, CHROMA_DC_BLOCK_INDEX, chroma_dc_scan, NULL, 4) < 0){
+                if( decode_residual(h, gb, h->mb + 256 + 16*4*chroma_idx, CHROMA_DC_BLOCK_INDEX+chroma_idx, chroma_dc_scan, NULL, 4) < 0){
                     return -1;
                 }
         }