[FFmpeg-devel] [PATCH] H.264: Fix poc for field pairs

[Jeff Downs]

Hi,

Attached patch fixes assignment of poc for field pairs.  Problem was 
discovered by Reinhard Nissl during recent thread "H.264 + PAFF: BBC HD 
recording shows extreme interlacing artefacts".

Currently, poc is getting assignment of lesser of the two local field poc 
variables which are based on information from current coded field only. 
Patch changes this to look at field pocs in current_picture_ptr, each 
determined properly during decode of the individual fields.

	-Jeff
-------------- next part --------------
Index: libavcodec/h264.c
===================================================================
--- libavcodec/h264.c	(revision 10933)
+++ libavcodec/h264.c	(working copy)
@@ -3767,8 +3767,10 @@
         s->current_picture_ptr->field_poc[1]= field_poc[1];
         s->current_picture_ptr->poc = field_poc[1];
     }
-    if(!FIELD_PICTURE || !s->first_field)
-        s->current_picture_ptr->poc= FFMIN(field_poc[0], field_poc[1]);
+    if(!FIELD_PICTURE || !s->first_field) {
+        Picture *cur = s->current_picture_ptr;
+        cur->poc= FFMIN(cur->field_poc[0], cur->field_poc[1]);
+    }
 
     return 0;
 }