May 19, 2021, 17:12 by d...@lynne.ee: > May 19, 2021, 03:44 by michael.di...@xaymar.com: > >> From: Michael Fabian 'Xaymar' Dirks <michael.di...@xaymar.com> >> >> Adds the "timestamp_precision" option to matroskaenc, which allows users >> to increase the time stamp precision up to 1 nanosecond. This aids with >> certain demuxers being unable to detect constant rate. It is a work >> around fix for the problems reported in 259, 6406, 7927, 8909 and 9124. >> >> Signed-off-by: Michael Fabian 'Xaymar' Dirks <michael.di...@xaymar.com> >> --- >> libavformat/matroskaenc.c | 25 ++++++++++++++++++------- >> 1 file changed, 18 insertions(+), 7 deletions(-) >> >> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c >> index b4284a8778..8e2813c36e 100644 >> --- a/libavformat/matroskaenc.c >> +++ b/libavformat/matroskaenc.c >> @@ -158,6 +158,8 @@ typedef struct MatroskaMuxContext { >> int default_mode; >> >> uint32_t segment_uid[4]; >> + >> + AVRational time_base; >> } MatroskaMuxContext; >> >> /** 2 bytes * 7 for EBML IDs, 7 1-byte EBML lengths, 6 1-byte uint, >> @@ -1816,6 +1818,7 @@ static int mkv_write_header(AVFormatContext *s) >> const AVDictionaryEntry *tag; >> int ret, i, version = 2; >> int64_t creation_time; >> + int64_t time_base = 1; >> >> if (mkv->mode != MODE_WEBM || >> av_dict_get(s->metadata, "stereo_mode", NULL, 0) || >> @@ -1852,7 +1855,10 @@ static int mkv_write_header(AVFormatContext *s) >> return ret; >> pb = mkv->info.bc; >> >> - put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000); >> + time_base = av_rescale_q(time_base, mkv->time_base, (AVRational){1, >> 1000000000}); >> + av_log(s, AV_LOG_DEBUG, "TimestampScale is: %" PRId64 " ns\n", >> time_base); >> + put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, time_base); >> + >> if ((tag = av_dict_get(s->metadata, "title", NULL, 0))) >> put_ebml_string(pb, MATROSKA_ID_TITLE, tag->value); >> if (!(s->flags & AVFMT_FLAG_BITEXACT)) { >> @@ -1885,11 +1891,11 @@ static int mkv_write_header(AVFormatContext *s) >> int64_t metadata_duration = get_metadata_duration(s); >> >> if (s->duration > 0) { >> - int64_t scaledDuration = av_rescale(s->duration, 1000, >> AV_TIME_BASE); >> + int64_t scaledDuration = av_rescale_q(s->duration, >> AV_TIME_BASE_Q, mkv->time_base); >> put_ebml_float(pb, MATROSKA_ID_DURATION, scaledDuration); >> av_log(s, AV_LOG_DEBUG, "Write early duration from recording time = %" >> PRIu64 "\n", scaledDuration); >> } else if (metadata_duration > 0) { >> - int64_t scaledDuration = av_rescale(metadata_duration, 1000, >> AV_TIME_BASE); >> + int64_t scaledDuration = av_rescale_q(metadata_duration, >> AV_TIME_BASE_Q, mkv->time_base); >> put_ebml_float(pb, MATROSKA_ID_DURATION, scaledDuration); >> av_log(s, AV_LOG_DEBUG, "Write early duration from metadata = %" PRIu64 >> "\n", scaledDuration); >> } else if (s->pb->seekable & AVIO_SEEKABLE_NORMAL) { >> @@ -1950,12 +1956,12 @@ static int mkv_write_header(AVFormatContext *s) >> // after 4k and on a keyframe >> if (IS_SEEKABLE(pb, mkv)) { >> if (mkv->cluster_time_limit < 0) >> - mkv->cluster_time_limit = 5000; >> + mkv->cluster_time_limit = av_rescale_q(5000, (AVRational){1, >> 1000}, mkv->time_base); >> if (mkv->cluster_size_limit < 0) >> mkv->cluster_size_limit = 5 * 1024 * 1024; >> } else { >> if (mkv->cluster_time_limit < 0) >> - mkv->cluster_time_limit = 1000; >> + mkv->cluster_time_limit = av_rescale_q(1000, (AVRational){1, >> 1000}, mkv->time_base); >> if (mkv->cluster_size_limit < 0) >> mkv->cluster_size_limit = 32 * 1024; >> } >> @@ -2736,8 +2742,8 @@ static int mkv_init(struct AVFormatContext *s) >> track->uid = mkv_get_uid(mkv->tracks, i, &c); >> } >> >> - // ms precision is the de-facto standard timescale for mkv files >> - avpriv_set_pts_info(st, 64, 1, 1000); >> + // Use user-defined timescale. >> + avpriv_set_pts_info(st, 64, mkv->time_base.num, mkv->time_base.den); >> >> if (st->codecpar->codec_type == AVMEDIA_TYPE_ATTACHMENT) { >> if (mkv->mode == MODE_WEBM) { >> @@ -2757,6 +2763,10 @@ static int mkv_init(struct AVFormatContext *s) >> track->track_num_size = ebml_num_size(track->track_num); >> } >> >> + // Scale the configured cluster_time_limit. >> + if (mkv->cluster_time_limit >= 0) >> + mkv->cluster_time_limit = av_rescale_q(mkv->cluster_time_limit, >> (AVRational){1, 1000}, mkv->time_base); >> + >> if (mkv->is_dash && nb_tracks != 1) >> return AVERROR(EINVAL); >> >> @@ -2824,6 +2834,7 @@ static const AVOption options[] = { >> { "infer", "For each track type, mark the first track of disposition >> default as default; if none exists, mark the first track as default.", 0, >> AV_OPT_TYPE_CONST, { .i64 = DEFAULT_MODE_INFER }, 0, 0, FLAGS, >> "default_mode" }, >> { "infer_no_subs", "For each track type, mark the first track of >> disposition default as default; for audio and video: if none exists, mark >> the first track as default.", 0, AV_OPT_TYPE_CONST, { .i64 = >> DEFAULT_MODE_INFER_NO_SUBS }, 0, 0, FLAGS, "default_mode" }, >> { "passthrough", "Use the disposition flag as-is", 0, AV_OPT_TYPE_CONST, { >> .i64 = DEFAULT_MODE_PASSTHROUGH }, 0, 0, FLAGS, "default_mode" }, >> + { "timestamp_precision", "Timestamp precision to use for the entire >> container", OFFSET(time_base), AV_OPT_TYPE_RATIONAL, { .dbl = 0.001 }, >> 0.000000001, 1.0, FLAGS}, >> { NULL }, >> }; >> > > Make the default 1 ns. > This is 2021. I'm not accepting any compromises. Matroska has > dragged its heels for long enough, video players have resorted to hacks > to fix time stamps, and high-framerate video is still unacceptably jittery. > > We're bumping to 5.0 next release anyway, and if any users have issues, > they can manually set this to 1ms. >
Or better yet, use the timebase to decide the value. That way, remuxing Matroska won't break anything, and the overhead will be lower. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".