Minor simplification of code in init_poc().

Originally committed as revision 14379 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h264.c

@@ -3699,10 +3699,9 @@ static int init_poc(H264Context *h){
     const int max_frame_num= 1<<h->sps.log2_max_frame_num;
     int field_poc[2];
 
+    h->frame_num_offset= h->prev_frame_num_offset;
     if(h->frame_num < h->prev_frame_num)
-        h->frame_num_offset= h->prev_frame_num_offset + max_frame_num;
-    else
-        h->frame_num_offset= h->prev_frame_num_offset;
+        h->frame_num_offset += max_frame_num;
 
     if(h->sps.poc_type==0){
         const int max_poc_lsb= 1<<h->sps.log2_max_poc_lsb;
@@ -3753,10 +3752,10 @@ static int init_poc(H264Context *h){
         if(s->picture_structure == PICT_FRAME)
             field_poc[1] += h->delta_poc[1];
     }else{
-        int poc;
+        int poc= 2*(h->frame_num_offset + h->frame_num);
 
-        if(h->nal_ref_idc) poc= 2*(h->frame_num_offset + h->frame_num);
-        else               poc= 2*(h->frame_num_offset + h->frame_num) - 1;
+        if(!h->nal_ref_idc)
+            poc--;
 
         field_poc[0]= poc;
         field_poc[1]= poc;