Allow to get the the track number in the IPRT (part) tag in AVI.

Patch by Panagiotis Issaris % takis P issaris A uhasselt P be %
Original thread:
Date: Sep 6, 2006 6:00 PM
Subject: [Ffmpeg-devel] [PATCH] Enable track tag in AVI

Originally committed as revision 6190 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/avidec.c

@@ -215,6 +215,7 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
     AVStream *st;
     AVIStream *ast = NULL;
     int xan_video = 0;  /* hack to support Xan A/V */
+    char str_track[4];
 
     avi->stream_index= -1;
 
@@ -479,6 +480,10 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
         case MKTAG('I', 'P', 'R', 'D'):
             avi_read_tag(pb, s->album, sizeof(s->album), size);
             break;
+        case MKTAG('I', 'P', 'R', 'T'):
+            avi_read_tag(pb, str_track, sizeof(str_track), size);
+            sscanf(str_track, "%d", &s->track);
+            break;
         default:
             /* skip tag */
             size += (size & 1);