h264: allow disabling bitstream overread protection by using the fast flag.

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

libavcodec/h264.c

@@ -188,9 +188,13 @@ const uint8_t *ff_h264_decode_nal(H264Context *h, const uint8_t *src, int *dst_l
     if(i>=length-1){ //no escaped 0
         *dst_length= length;
         *consumed= length+1; //+1 for the header
+        if(h->s.avctx->flags2 & CODEC_FLAG2_FAST){
+            return src;
+        }else{
             memcpy(dst, src, length);
             return dst;
         }
+    }
 
 //printf("decoding esc\n");
     memcpy(dst, src, i);