ffmpeg source update for sep 09

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

Index: source/patched-ffmpeg-mt/libavformat/avidec.c
===================================================================
--- source/patched-ffmpeg-mt/libavformat/avidec.c	(revision 59334)
+++ source/patched-ffmpeg-mt/libavformat/avidec.c	(working copy)
@@ -759,7 +759,7 @@
     for (i=0; i<s->nb_streams; i++) {
         st  = s->streams[i];
         ast = st->priv_data;
-        if (st->discard < AVDISCARD_ALL && ast->sub_pkt.data) {
+        if (st->discard < AVDISCARD_ALL && ast && ast->sub_pkt.data) {
             ts = av_rescale_q(ast->sub_pkt.dts, st->time_base, AV_TIME_BASE_Q);
             if (ts <= next_ts && ts < ts_min) {
                 ts_min = ts;
@@ -1294,12 +1294,14 @@
         AVStream *st = s->streams[i];
         AVIStream *ast = st->priv_data;
         av_free(st->codec->palctrl);
-        if (ast->sub_ctx) {
-            av_freep(&ast->sub_ctx->pb);
-            av_close_input_stream(ast->sub_ctx);
+        if (ast) {
+            if (ast->sub_ctx) {
+                av_freep(&ast->sub_ctx->pb);
+                av_close_input_stream(ast->sub_ctx);
+            }
+            av_free(ast->sub_buffer);
+            av_free_packet(&ast->sub_pkt);
         }
-        av_free(ast->sub_buffer);
-        av_free_packet(&ast->sub_pkt);
     }
 
     if (avi->dv_demux)