VP8: partially inline decode_block_coeffs

Avoids a function call in the case of empty DCT blocks (most of the time).

Originally committed as revision 24691 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/vp8.c

@@ -821,18 +821,13 @@ void decode_mb_mode(VP8Context *s, VP8Macroblock *mb, int mb_x, int mb_y, uint8_
  * @return 0 if no coeffs were decoded
  *         otherwise, the index of the last coeff decoded plus one
  */
-static int decode_block_coeffs(VP56RangeCoder *c, DCTELEM block[16],
-                               uint8_t probs[8][3][NUM_DCT_TOKENS-1],
-                               int i, int zero_nhood, int16_t qmul[2])
+static int decode_block_coeffs_internal(VP56RangeCoder *c, DCTELEM block[16],
+                                        uint8_t probs[8][3][NUM_DCT_TOKENS-1],
+                                        int i, uint8_t *token_prob, int16_t qmul[2])
 {
-    uint8_t *token_prob = probs[i][zero_nhood];
-    int coeff;
-
-    if (!vp56_rac_get_prob_branchy(c, token_prob[0]))
-        return 0;
     goto skip_eob;
-
     do {
+        int coeff;
         if (!vp56_rac_get_prob_branchy(c, token_prob[0]))   // DCT_EOB
             return i;
 
@@ -879,6 +874,17 @@ skip_eob:
     return i;
 }
 
+static av_always_inline
+int decode_block_coeffs(VP56RangeCoder *c, DCTELEM block[16],
+                        uint8_t probs[8][3][NUM_DCT_TOKENS-1],
+                        int i, int zero_nhood, int16_t qmul[2])
+{
+    uint8_t *token_prob = probs[i][zero_nhood];
+    if (!vp56_rac_get_prob_branchy(c, token_prob[0]))   // DCT_EOB
+        return 0;
+    return decode_block_coeffs_internal(c, block, probs, i, token_prob, qmul);
+}
+
 static av_always_inline
 void decode_mb_coeffs(VP8Context *s, VP56RangeCoder *c, VP8Macroblock *mb,
                       uint8_t t_nnz[9], uint8_t l_nnz[9])