avcodec/h264_refs: Allow slightly larger pps_ref_count[0] in PAFF RAP detection heuristic

Fixes Ticket4738
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/h264_refs.c

@@ -810,7 +810,8 @@ int ff_h264_execute_ref_pic_marking(H264Context *h, MMCO *mmco, int mmco_count)
 
     if (   err >= 0
         && h->long_ref_count==0
-        && (h->short_ref_count<=2 || pps_ref_count[0] <= 1 && pps_ref_count[1] <= 1)
+        && (   h->short_ref_count<=2
+            || pps_ref_count[0] <= 1 + (h->picture_structure != PICT_FRAME) && pps_ref_count[1] <= 1)
         && pps_ref_count[0]<=2 + (h->picture_structure != PICT_FRAME) + (2*!h->has_recovery_point)
         && h->cur_pic_ptr->f->pict_type == AV_PICTURE_TYPE_I){
         h->cur_pic_ptr->recovered |= 1;