Merge commit '9455a023be9f3915ccf5511a0b8fdb5b8897b2b6' into release/1.1

* commit '9455a023be9f3915ccf5511a0b8fdb5b8897b2b6':
  matroskaenc: do not write negative timestamps

Conflicts:
	tests/ref/lavf/mkv
	tests/ref/seek/lavf-mkv

No change to fate as ffmpeg was not affected by these bugs

Merged-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 12 insertions, 1 deletions

diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 38cd6a92ed..a8b829c3b3 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -95,6 +95,8 @@ typedef struct MatroskaMuxContext {
     AVPacket        cur_audio_pkt;
 
     int have_attachments;
+
+    int64_t ts_offset;
 } MatroskaMuxContext;
 
 
@@ -1265,9 +1267,18 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
     AVIOContext *pb = s->pb->seekable ? s->pb : mkv->dyn_bc;
     AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
     int ret, keyframe = !!(pkt->flags & AV_PKT_FLAG_KEY);
-    int64_t ts = mkv->tracks[pkt->stream_index].write_dts ? pkt->dts : pkt->pts;
+    int64_t ts;
     int cluster_size = avio_tell(pb) - (s->pb->seekable ? mkv->cluster_pos : 0);
 
+    if (pkt->dts < 0 && !mkv->ts_offset)
+        mkv->ts_offset = -pkt->dts;
+
+    pkt->dts += mkv->ts_offset;
+    if (pkt->pts != AV_NOPTS_VALUE)
+        pkt->pts += mkv->ts_offset;
+
+    ts = mkv->tracks[pkt->stream_index].write_dts ? pkt->dts : pkt->pts;
+
     // start a new cluster every 5 MB or 5 sec, or 32k / 1 sec for streaming or
     // after 4k and on a keyframe
     if (mkv->cluster_pos != -1 &&