[FFmpeg-cvslog] avformat/matroskadec: ignore CodecPrivate if the stream is VP9

[James Almer]

ffmpeg | branch: release/3.4 | James Almer <jamrial at gmail.com> | Sat Jan 13 16:04:21 2018 -0300| [3fdff40a32e31b8bfe9127841f75472f20e30354] | committer: James Almer

avformat/matroskadec: ignore CodecPrivate if the stream is VP9

Defined in a recent revision of https://www.webmproject.org/docs/container/

This prevents storing the contents of CodecPrivate into extradata for
a codec that doesn't need nor expect any. It will among other things
prevent matroska specific binary data from being dumped onto other
formats during remuxing.

Signed-off-by: James Almer <jamrial at gmail.com>
(cherry picked from commit acdea9e7c56b74b05c56b4733acc855b959ba073)

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=3fdff40a32e31b8bfe9127841f75472f20e30354
---

 libavformat/matroskadec.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index e6631097b8..95189525e3 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -2390,6 +2390,10 @@ static int matroska_parse_tracks(AVFormatContext *s)
                 return ret;
         } else if (codec_id == AV_CODEC_ID_PRORES && track->codec_priv.size == 4) {
             fourcc = AV_RL32(track->codec_priv.data);
+        } else if (codec_id == AV_CODEC_ID_VP9 && track->codec_priv.size) {
+            /* we don't need any value stored in CodecPrivate.
+               make sure that it's not exported as extradata. */
+            track->codec_priv.size = 0;
         }
         track->codec_priv.size -= extradata_offset;