avcodec/h264_ps: try to support Ambarella AVC

Fixes Ticket2763

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

libavcodec/h264_ps.c

@@ -224,6 +224,11 @@ static inline int decode_vui_parameters(H264Context *h, SPS *sps){
         get_ue_golomb(&h->gb);  /* chroma_sample_location_type_bottom_field */
     }
 
+    if (show_bits1(&h->gb) && get_bits_left(&h->gb) < 10) {
+        av_log(h->avctx, AV_LOG_WARNING, "Truncated VUI\n");
+        return 0;
+    }
+
     sps->timing_info_present_flag = get_bits1(&h->gb);
     if(sps->timing_info_present_flag){
         sps->num_units_in_tick = get_bits_long(&h->gb, 32);