segment: fix copying stream metadata

To get mpegts metadata copied when segmenting.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/segment.c

@@ -160,6 +160,7 @@ static int segment_mux_init(AVFormatContext *s)
             ocodec->codec_tag = 0;
         }
         st->sample_aspect_ratio = s->streams[i]->sample_aspect_ratio;
+        av_dict_copy(&st->metadata, s->streams[i]->metadata, 0);
     }
 
     return 0;