Namely, that it should not be called if you are starting to decode a B
frame without any reference pictures.
Prevents an endless allocation cycle in MPV_frame_start that will end in
picture buffer overflow and abort.
Fixes roundup issue 216.
Originally committed as revision 11214 to svn://svn.ffmpeg.org/ffmpeg/trunk
h->slice_type= slice_type;
s->pict_type= h->slice_type; // to make a few old func happy, it's wrong though
+ if (s->pict_type == B_TYPE && s->last_picture_ptr == NULL) {
+ av_log(h->s.avctx, AV_LOG_ERROR,
+ "B picture before any references, skipping\n");
+ return -1;
+ }
pps_id= get_ue_golomb(&s->gb);
if(pps_id>=MAX_PPS_COUNT){