H.264: decode arbitrary frame orders and allow B-frames as references.

Originally committed as revision 4003 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mpegvideo.c

@@ -1471,7 +1471,8 @@ alloc:
             pic= (AVFrame*)&s->picture[i];
         }
 
-        pic->reference= s->pict_type != B_TYPE && !s->dropable ? 3 : 0;
+        pic->reference= (s->pict_type != B_TYPE || s->codec_id == CODEC_ID_H264)
+                        && !s->dropable ? 3 : 0;
 
         pic->coded_picture_number= s->coded_picture_number++;
         
@@ -1566,7 +1567,7 @@ void MPV_frame_end(MpegEncContext *s)
         XVMC_field_end(s);
     }else
 #endif
-    if(s->unrestricted_mv && s->pict_type != B_TYPE && !s->intra_only && !(s->flags&CODEC_FLAG_EMU_EDGE)) {
+    if(s->unrestricted_mv && s->current_picture.reference && !s->intra_only && !(s->flags&CODEC_FLAG_EMU_EDGE)) {
             draw_edges(s->current_picture.data[0], s->linesize  , s->h_edge_pos   , s->v_edge_pos   , EDGE_WIDTH  );
             draw_edges(s->current_picture.data[1], s->uvlinesize, s->h_edge_pos>>1, s->v_edge_pos>>1, EDGE_WIDTH/2);
             draw_edges(s->current_picture.data[2], s->uvlinesize, s->h_edge_pos>>1, s->v_edge_pos>>1, EDGE_WIDTH/2);

libavcodec/mpegvideo.h

@@ -173,6 +173,8 @@ typedef struct Picture{
     int frame_num;              ///< h264 frame_num
     int pic_id;                 ///< h264 pic_num or long_term_pic_idx
     int long_ref;               ///< 1->long term reference 0->short term reference
+    int ref_poc[2][16];         ///< h264 POCs of the frames used as reference
+    int ref_count[2];           ///< number of entries in ref_poc
 
     int mb_var_sum;             ///< sum of MB variance for current frame 
     int mc_mb_var_sum;          ///< motion compensated MB variance for current frame