Use last decoded SPS as current SPS in order to parse picture timing SEI

correctly. This works around an apparent H.264 standard deficiency.

Patch by Ivan Schreter, schreter gmx net

Originally committed as revision 17471 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h264.c

@@ -7223,6 +7223,7 @@ static inline int decode_seq_parameter_set(H264Context *h){
 
     av_free(h->sps_buffers[sps_id]);
     h->sps_buffers[sps_id]= sps;
+    h->sps = *sps;
     return 0;
 fail:
     av_free(sps);