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

patches/to_upstream/24_ogg_index.patch

+diff -wurp -N orig/libavformat/oggdec.c ffmpeg-mt/libavformat/oggdec.c
+--- orig/libavformat/oggdec.c   2011-02-25 03:23:22.663626821 -0800
++++ ffmpeg-mt/libavformat/oggdec.c      2011-02-25 07:30:11.045572658 -0800
+@@ -610,10 +610,9 @@ ogg_read_timestamp (AVFormatContext * s,
+                     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 @@ ogg_read_timestamp (AVFormatContext * s,
+ 
+     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 @@ static int ogg_read_seek(AVFormatContext
+         os->keyframe_seek = 1;
+ 
+     ret = av_seek_frame_binary(s, stream_index, timestamp, flags);
++    os = ogg->streams + stream_index;
+     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;
+ 
+     // Since we have seeked to the beginning then reset lastpts and lastdts to 0.
+     if (!seek_pts) {