avconv: check that the output format context exists before accessing it

Fixes a segfault in exit_program() if opening an output file fails.

1 files changed, 1 insertions, 1 deletions

diff --git a/avconv.c b/avconv.c
index cce9a83e6a..480823506f 100644
--- a/avconv.c
+++ b/avconv.c
@@ -167,7 +167,7 @@ static void exit_program(void)
     /* close files */
     for (i = 0; i < nb_output_files; i++) {
         AVFormatContext *s = output_files[i]->ctx;
-        if (!(s->oformat->flags & AVFMT_NOFILE) && s->pb)
+        if (s && s->oformat && !(s->oformat->flags & AVFMT_NOFILE) && s->pb)
             avio_close(s->pb);
         avformat_free_context(s);
         av_dict_free(&output_files[i]->opts);