[FFmpeg-cvslog] avcodec/vc1: fix B predictor validity for 4-MV MBs

[Jerome Borsboom]

ffmpeg | branch: master | Jerome Borsboom <jerome.borsboom at carpalis.nl> | Mon Jan 14 09:05:24 2019 +0100| [fc6e53b0b662c60560dff75cc93248f72d0faf8a] | committer: Carl Eugen Hoyos

avcodec/vc1: fix B predictor validity for 4-MV MBs

The B predictor for 4-MV MBs in interlace field pictures is not used
for blocks 0 and 2 when the picture is 1 MB wide.

Signed-off-by: Jerome Borsboom <jerome.borsboom at carpalis.nl>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=fc6e53b0b662c60560dff75cc93248f72d0faf8a
---

 libavcodec/vc1_pred.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/vc1_pred.c b/libavcodec/vc1_pred.c
index 8b5a9ead0b..9e29b44a1f 100644
--- a/libavcodec/vc1_pred.c
+++ b/libavcodec/vc1_pred.c
@@ -289,6 +289,8 @@ void ff_vc1_pred_mv(VC1Context *v, int n, int dmv_x, int dmv_y,
         case 3:
             off = -1;
         }
+        if (v->field_mode && s->mb_width == 1)
+            b_valid = b_valid && c_valid;
     }
 
     if (v->field_mode) {