The value zero for AVPacket.duration means that the duration is unknown,
which in practice means "play this subtitle until overridden by the next
subtitle". Yet for Matroska a BlockGroup with duration zero means
that the subtitle really has a duration zero. "Display until overridden"
is achieved by not setting a duration on the container level at all and
this is achieved by using a SimpleBlock or a BlockGroup without
duration. This commit implements this.
Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com>
---
libavformat/matroskaenc.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index a4ddf1fa6a..725e44c962 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -585,7 +585,7 @@ static int mkv_assemble_cues(AVStream **streams,
AVIOContext *dyn_cp,
put_ebml_uint(cuepoint, MATROSKA_ID_CUETRACK ,
tracks[idx].track_num);
put_ebml_uint(cuepoint, MATROSKA_ID_CUECLUSTERPOSITION ,
entry->cluster_pos);
put_ebml_uint(cuepoint, MATROSKA_ID_CUERELATIVEPOSITION,
entry->relative_pos);
- if (entry->duration != -1)
+ if (entry->duration > 0)
put_ebml_uint(cuepoint, MATROSKA_ID_CUEDURATION ,
entry->duration);
end_ebml_master(cuepoint, track_positions);
} while (++entry < end && entry->pts == pts);
@@ -2307,7 +2307,7 @@ static int mkv_write_packet_internal(AVFormatContext *s,
const AVPacket *pkt)
AVCodecParameters *par = s->streams[pkt->stream_index]->codecpar;
mkv_track *track = &mkv->tracks[pkt->stream_index];
int keyframe = !!(pkt->flags & AV_PKT_FLAG_KEY);
- int duration = pkt->duration;
+ int64_t duration = pkt->duration;
int ret;
int64_t ts = track->write_dts ? pkt->dts : pkt->pts;
int64_t relative_packet_pos;
@@ -2344,14 +2344,17 @@ static int mkv_write_packet_internal(AVFormatContext
*s, const AVPacket *pkt)
relative_packet_pos = avio_tell(pb);
- if (par->codec_type != AVMEDIA_TYPE_SUBTITLE) {
+ if (par->codec_type != AVMEDIA_TYPE_SUBTITLE ||
+ (par->codec_id != AV_CODEC_ID_WEBVTT && duration <= 0)) {
ret = mkv_write_block(s, pb, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe);
if (ret < 0)
return ret;
if (keyframe && IS_SEEKABLE(s->pb, mkv) &&
- (par->codec_type == AVMEDIA_TYPE_VIDEO || !mkv->have_video &&
!track->has_cue)) {
+ (par->codec_type == AVMEDIA_TYPE_VIDEO ||
+ par->codec_type == AVMEDIA_TYPE_SUBTITLE ||
+ !mkv->have_video && !track->has_cue)) {
ret = mkv_add_cuepoint(mkv, pkt->stream_index, ts,
- mkv->cluster_pos, relative_packet_pos, -1);
+ mkv->cluster_pos, relative_packet_pos, 0);
if (ret < 0)
return ret;
track->has_cue = 1;
--
2.27.0
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