h264: try reading SPS with wrong escaping, it sometimes works better

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

libavcodec/h264.c

@@ -3801,7 +3801,11 @@ static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size){
             break;
         case NAL_SPS:
             init_get_bits(&s->gb, ptr, bit_length);
-            ff_h264_decode_seq_parameter_set(h);
+            if(ff_h264_decode_seq_parameter_set(h) < 0 && h->is_avc && (nalsize != consumed) && nalsize){
+                av_log(h->s.avctx, AV_LOG_DEBUG, "SPS decoding failure, trying alternative mode\n");
+                init_get_bits(&s->gb, &buf[buf_index + 1 - consumed], 8*nalsize);
+                ff_h264_decode_seq_parameter_set(h);
+            }
 
             if (s->flags& CODEC_FLAG_LOW_DELAY ||
                 (h->sps.bitstream_restriction_flag && !h->sps.num_reorder_frames))

libavcodec/h264_ps.c

@@ -228,7 +228,6 @@ static inline int decode_vui_parameters(H264Context *h, SPS *sps){
         get_ue_golomb(&s->gb); /*max_dec_frame_buffering*/
 
         if(s->gb.size_in_bits < get_bits_count(&s->gb)){
-            av_log(h->s.avctx, AV_LOG_ERROR, "Overread VUI by %d bits\n", get_bits_count(&s->gb) - s->gb.size_in_bits);
             sps->num_reorder_frames=0;
             sps->bitstream_restriction_flag= 0;
         }
@@ -238,6 +237,10 @@ static inline int decode_vui_parameters(H264Context *h, SPS *sps){
             return -1;
         }
     }
+    if(s->gb.size_in_bits < get_bits_count(&s->gb)){
+        av_log(h->s.avctx, AV_LOG_ERROR, "Overread VUI by %d bits\n", get_bits_count(&s->gb) - s->gb.size_in_bits);
+        return -1;
+    }
 
     return 0;
 }