Initialize a variable, and revalidate indexes when necessary....

source/patched-ffmpeg-mt/libavformat/oggdec.c

Index: source/patched-ffmpeg-mt/libavformat/oggdec.c
===================================================================
--- source/patched-ffmpeg-mt/libavformat/oggdec.c	(revision 76041)
+++ source/patched-ffmpeg-mt/libavformat/oggdec.c	(working copy)
@@ -610,10 +610,9 @@
                     int64_t pos_limit)
 {
     struct ogg *ogg = s->priv_data;
-    struct ogg_stream *os = ogg->streams + stream_index;
     ByteIOContext *bc = s->pb;
     int64_t pts = AV_NOPTS_VALUE;
-    int i;
+    int i = -1;
     int packet = 0;
     int64_t start_pos = *pos_arg;
     url_fseek(bc, *pos_arg, SEEK_SET);
@@ -621,6 +620,7 @@
 
     while (url_ftell(bc) < pos_limit && !ogg_packet(s, &i, NULL, NULL, pos_arg)) {
         if (i == stream_index) {
+            struct ogg_stream *os = ogg->streams + stream_index;
             pts = ogg_calc_pts(s, i, NULL);
             if (os->keyframe_seek && !(os->pflags & AV_PKT_FLAG_KEY))
                 pts = AV_NOPTS_VALUE;
@@ -655,12 +655,14 @@
         os->keyframe_seek = 1;
 
     ret = av_seek_frame_binary(s, stream_index, timestamp, flags);
+    os = ogg->streams + stream_index;

[scherkus (not reviewing), 2011/02/26 00:42:27]

I'm lost as to what's changing streams/stream_index to force us to re-evaluate
os

     if (ret < 0)
         os->keyframe_seek = 0;
 
     // Save the position seeked to.
     pos_arg = seek_pos = url_ftell(s->pb);
     seek_pts = ogg_read_timestamp(s, stream_index, &pos_arg, url_fsize(s->pb));
+    os = ogg->streams + stream_index;

[scherkus (not reviewing), 2011/02/26 00:42:27]

ditto!

 
     // Since we have seeked to the beginning then reset lastpts and lastdts to 0.
     if (!seek_pts) {