h264: allow debuging SEI types

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/h264_sei.c

@@ -177,6 +177,9 @@ int ff_h264_decode_sei(H264Context *h){
             size+= show_bits(&s->gb, 8);
         }while(get_bits(&s->gb, 8) == 255);
 
+        if(s->avctx->debug&FF_DEBUG_STARTCODE)
+            av_log(h->s.avctx, AV_LOG_DEBUG, "SEI %d len:%d\n", type, size);
+
         switch(type){
         case SEI_TYPE_PIC_TIMING: // Picture timing SEI
             if(decode_picture_timing(h) < 0)