[FFmpeg-cvslog] avformat/webmdashenc: Don't pass NULL to memcmp

[Andreas Rheinhardt]

ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Mon Sep 23 23:23:10 2019 +0200| [a42c47b77feda837a966aa96569ed8a2553b1c36] | committer: Andreas Rheinhardt

avformat/webmdashenc: Don't pass NULL to memcmp

Affects the FATE-tests webm-dash-manifest-unaligned-video-streams,
webm-dash-manifest and webm-dash-manifest-representations.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a42c47b77feda837a966aa96569ed8a2553b1c36
---

 libavformat/webmdashenc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/webmdashenc.c b/libavformat/webmdashenc.c
index 332d0466e1..1304c1a8c3 100644
--- a/libavformat/webmdashenc.c
+++ b/libavformat/webmdashenc.c
@@ -155,7 +155,8 @@ static int bitstream_switching(AVFormatContext *s, const AdaptationSet *as)
             !av_strstart(track_num->value, gold_track_num->value, NULL) ||
             gold_par->codec_id != par->codec_id ||
             gold_par->extradata_size != par->extradata_size ||
-            memcmp(gold_par->extradata, par->extradata, par->extradata_size)) {
+            (par->extradata_size > 0 &&
+             memcmp(gold_par->extradata, par->extradata, par->extradata_size))) {
             return 0;
         }
     }