[FFmpeg-cvslog] vp56: Remove clear_blocks call, and clear alpha plane U/V DC only

[Ronald S. Bultje]

ffmpeg | branch: master | Ronald S. Bultje <rsbultje at gmail.com> | Fri Feb  1 11:04:50 2013 -0800| [f859678f3f274bbfa8228ddf13706f55d66481cb] | committer: Martin Storsjö

vp56: Remove clear_blocks call, and clear alpha plane U/V DC only

The non-alpha and alpha-Y planes are cleared in the idct_put/add()
calls. For the alpha U/V planes, we only care about the DC for entropy
context prediction purposes, the rest of the data is unused.

Signed-off-by: Martin Storsjö <martin at martin.st>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f859678f3f274bbfa8228ddf13706f55d66481cb
---

 libavcodec/vp56.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/libavcodec/vp56.c b/libavcodec/vp56.c
index dec7869..64f33c6 100644
--- a/libavcodec/vp56.c
+++ b/libavcodec/vp56.c
@@ -394,8 +394,6 @@ static void vp56_decode_mb(VP56Context *s, int row, int col, int is_alpha)
         mb_type = vp56_decode_mv(s, row, col);
     ref_frame = vp56_reference_frame[mb_type];
 
-    s->dsp.clear_blocks(*s->block_coeff);
-
     s->parse_coeff(s);
 
     vp56_add_predictors_dc(s, ref_frame);
@@ -448,6 +446,11 @@ static void vp56_decode_mb(VP56Context *s, int row, int col, int is_alpha)
             }
             break;
     }
+
+    if (is_alpha) {
+        s->block_coeff[4][0] = 0;
+        s->block_coeff[5][0] = 0;
+    }
 }
 
 static int vp56_size_changed(AVCodecContext *avctx)