faster residual

encoder/cabac.c

@@ -717,7 +717,7 @@ static void block_residual_write_cabac( x264_t *h, x264_cabac_t *cb, int i_ctxBl
     int i_last  = 0;
     int i_sigmap_size;
     int node_ctx = 0;
-    int i;
+    int i, j;
 
     const int *significant_coeff_flag_offset;
     const int *last_coeff_flag_offset;
@@ -730,17 +730,17 @@ static void block_residual_write_cabac( x264_t *h, x264_cabac_t *cb, int i_ctxBl
      *                5-> Luma8x8   i_idx = luma8x8idx
      */
 
-    for( i = 0; i < i_count; i++ )
-    {
+    for( j = i_count - 4; j >= 0; j -= 4 )
+        if( *(uint64_t*)(l+j) )
+            break;
+    for( i = 0; i < j+4; i++ )
         if( l[i] != 0 )
         {
-            i_coeff_abs_m1[i_coeff] = abs( l[i] ) - 1;
-            i_coeff_sign[i_coeff]   = ( l[i] < 0 );
+            i_coeff_abs_m1[i_coeff] = abs(l[i]) - 1;
+            i_coeff_sign[i_coeff]   = l[i] < 0;
             i_coeff++;
-
             i_last = i;
         }
-    }
 
     if( i_count != 64 )
     {

encoder/cavlc.c

@@ -70,17 +70,15 @@ static void block_residual_write_cavlc( x264_t *h, bs_t *s, int i_idx, int16_t *
     int i_total_zero;
     int i_last;
     unsigned int i_sign;
-
     int i;
-    int i_zero_left;
     int i_suffix_length;
 
     /* first find i_last */
-    i_last = i_count - 1;
+    for( i_last = i_count-1; i_last >= 3; i_last -= 4 )
+        if( *(uint64_t*)(l+i_last-3) )
+            break;
     while( i_last >= 0 && l[i_last] == 0 )
-    {
         i_last--;
-    }
 
     i_sign = 0;
     i_total = 0;
@@ -94,16 +92,11 @@ static void block_residual_write_cavlc( x264_t *h, bs_t *s, int i_idx, int16_t *
         /* level and run and total */
         while( i_last >= 0 )
         {
-            level[idx] = l[i_last--];
-
-            run[idx] = 0;
-            while( i_last >= 0 && l[i_last] == 0 )
-            {
-                run[idx]++;
-                i_last--;
-            }
-
-            idx++;
+            int r = 0;
+            level[idx] = l[i_last];
+            while( --i_last >= 0 && l[i_last] == 0 )
+                r++;
+            run[idx++] = r;
         }
 
         i_total = idx;
@@ -112,7 +105,7 @@ static void block_residual_write_cavlc( x264_t *h, bs_t *s, int i_idx, int16_t *
         i_trailing = X264_MIN(3, idx);
         for( idx = 0; idx < i_trailing; idx++ )
         {
-            if( abs(level[idx]) > 1 )
+            if( (unsigned)(level[idx]+1) > 2 )
             {
                 i_trailing = idx;
                 break;
@@ -136,9 +129,7 @@ static void block_residual_write_cavlc( x264_t *h, bs_t *s, int i_idx, int16_t *
     }
 
     if( i_total <= 0 )
-    {
         return;
-    }
 
     i_suffix_length = i_total > 10 && i_trailing < 3 ? 1 : 0;
     if( i_trailing > 0 )
@@ -147,29 +138,18 @@ static void block_residual_write_cavlc( x264_t *h, bs_t *s, int i_idx, int16_t *
     }
     for( i = i_trailing; i < i_total; i++ )
     {
-        unsigned int i_level_code;
+        int mask = level[i] >> 15;
+        int abs_level = (level[i]^mask)-mask;
+        int i_level_code = abs_level*2-mask-2;
 
-        /* calculate level code */
-        if( level[i] < 0 )
-        {
-            i_level_code = -2*level[i] - 1;
-        }
-        else /* if( level[i] > 0 ) */
-        {
-            i_level_code = 2 * level[i] - 2;
-        }
         if( i == i_trailing && i_trailing < 3 )
-        {
             i_level_code -= 2; /* as level[i] can't be 1 for the first one if i_trailing < 3 */
-        }
 
         if( ( i_level_code >> i_suffix_length ) < 14 )
         {
             bs_write_vlc( s, x264_level_prefix[i_level_code >> i_suffix_length] );
             if( i_suffix_length > 0 )
-            {
                 bs_write( s, i_suffix_length, i_level_code );
-            }
         }
         else if( i_suffix_length == 0 && i_level_code < 30 )
         {
@@ -186,54 +166,31 @@ static void block_residual_write_cavlc( x264_t *h, bs_t *s, int i_idx, int16_t *
             bs_write_vlc( s, x264_level_prefix[15] );
             i_level_code -= 15 << i_suffix_length;
             if( i_suffix_length == 0 )
-            {
                 i_level_code -= 15;
-            }
-
             if( i_level_code >= 1<<12 )
-            {
                 x264_log(h, X264_LOG_WARNING, "OVERFLOW levelcode=%d\n", i_level_code );
-            }
-
             bs_write( s, 12, i_level_code );
         }
 
         if( i_suffix_length == 0 )
-        {
             i_suffix_length++;
-        }
-        if( abs( level[i] ) > ( 3 << ( i_suffix_length - 1 ) ) && i_suffix_length < 6 )
-        {
+        if( abs_level > (3 << (i_suffix_length-1)) && i_suffix_length < 6 )
             i_suffix_length++;
-        }
     }
 
     if( i_total < i_count )
     {
         if( i_idx == BLOCK_INDEX_CHROMA_DC )
-        {
             bs_write_vlc( s, x264_total_zeros_dc[i_total-1][i_total_zero] );
-        }
         else
-        {
             bs_write_vlc( s, x264_total_zeros[i_total-1][i_total_zero] );
-        }
     }
 
-    for( i = 0, i_zero_left = i_total_zero; i < i_total - 1; i++ )
+    for( i = 0; i < i_total-1 && i_total_zero > 0; i++ )
     {
-        int i_zl;
-
-        if( i_zero_left <= 0 )
-        {
-            break;
-        }
-
-        i_zl = X264_MIN( i_zero_left - 1, 6 );
-
+        int i_zl = X264_MIN( i_total_zero - 1, 6 );
         bs_write_vlc( s, x264_run_before[i_zl][run[i]] );
-
-        i_zero_left -= run[i];
+        i_total_zero -= run[i];
     }
 }