In order to determine whether the current cluster needs to be closed
because of the limits on cluster-size and cluster-time,
mkv_write_packet() would first get the size of the current cluster via
applying avio_tell() on the dynamic buffer holding the current cluster.
It did this without checking whether there is an open cluster right now,
so that avio_tell() returned AVERROR(EINVAL) which worked as expected
because the return value was put into a signed type (the call was
unchecked).
This is not good as it relied on avio_tell() (or actually, avio_seek())
to handle the case of an inexistent AVIOContext gracefully.
Fixing this is easy: Only check if a cluster needs to be closed if a
cluster is in fact open.
Essentially the same happened with the tags in mkv_write_trailer(). It
has been fixed, too.
Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@gmail.com>
---
I wonder whether we should rather check mkv->cluster_bc instead of
mkv->cluster_pos != -1. I would have made a commit to do so if I
understood this avio_write_marker stuff that seems be broken better (the
check below should probably be mkv->cluster_pos != -1 instead of != 0).
If opening a cluster fails, mkv->cluster_pos is still set; such problems
would be automatically fixed by such a switch.
libavformat/matroskaenc.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 39ad5d1ccf..f84e50f94e 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -2354,6 +2354,7 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket
*pkt)
if (ret < 0)
return ret;
+ if (mkv->cluster_pos != -1) {
if (mkv->tracks[pkt->stream_index].write_dts)
cluster_time = pkt->dts - mkv->cluster_pts;
else
@@ -2381,9 +2382,10 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket
*pkt)
start_new_cluster = 0;
}
- if (mkv->cluster_pos != -1 && start_new_cluster) {
+ if (start_new_cluster) {
mkv_end_cluster(s);
}
+ }
if (!mkv->cluster_pos)
avio_write_marker(s->pb,
@@ -2498,7 +2500,7 @@ static int mkv_write_trailer(AVFormatContext *s)
end_ebml_master_crc32(pb, &mkv->tracks_bc, mkv);
// update stream durations
- if (!mkv->is_live) {
+ if (mkv->tags_bc) {
int i;
int64_t curr = avio_tell(mkv->tags_bc);
for (i = 0; i < s->nb_streams; ++i) {
@@ -2522,8 +2524,6 @@ static int mkv_write_trailer(AVFormatContext *s)
}
}
avio_seek(mkv->tags_bc, curr, SEEK_SET);
- }
- if (mkv->tags_bc && !mkv->is_live) {
avio_seek(pb, mkv->tags_pos, SEEK_SET);
end_ebml_master_crc32(pb, &mkv->tags_bc, mkv);
}
--
2.20.1
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