[FFmpeg-cvslog] r20666 - trunk/libavcodec/mpeg12.c

[michael]

Author: michael
Date: Mon Nov 30 03:37:03 2009
New Revision: 20666

Log:
Fix dual prime motion compensation in field pictures.
Fixes issue1125.

Modified:
   trunk/libavcodec/mpeg12.c

Modified: trunk/libavcodec/mpeg12.c
==============================================================================
--- trunk/libavcodec/mpeg12.c	Mon Nov 30 00:30:46 2009	(r20665)
+++ trunk/libavcodec/mpeg12.c	Mon Nov 30 03:37:03 2009	(r20666)
@@ -448,18 +448,20 @@ static int mpeg_decode_mb(MpegEncContext
                 for(i=0;i<2;i++) {
                     if (USES_LIST(mb_type, i)) {
                         int dmx, dmy, mx, my, m;
+                        const int my_shift= s->picture_structure == PICT_FRAME;
+
                         mx = mpeg_decode_motion(s, s->mpeg_f_code[i][0],
                                                 s->last_mv[i][0][0]);
                         s->last_mv[i][0][0] = mx;
                         s->last_mv[i][1][0] = mx;
                         dmx = get_dmv(s);
                         my = mpeg_decode_motion(s, s->mpeg_f_code[i][1],
-                                                s->last_mv[i][0][1] >> 1);
+                                                s->last_mv[i][0][1] >> my_shift);
                         dmy = get_dmv(s);
 
 
-                        s->last_mv[i][0][1] = my<<1;
-                        s->last_mv[i][1][1] = my<<1;
+                        s->last_mv[i][0][1] = my<<my_shift;
+                        s->last_mv[i][1][1] = my<<my_shift;
 
                         s->mv[i][0][0] = mx;
                         s->mv[i][0][1] = my;