Jan 13, 2021, 18:46 by tfo...@gmail.com:
By default the time code scale in a MKV file in millisecond. With this
option we can set the time code scale to microsecond or nanoseconds for
very high frame rate.
---
libavformat/matroskaenc.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 233c472b8f..cfad6a4693 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -158,6 +158,8 @@ typedef struct MatroskaMuxContext {
int default_mode;
uint32_t segment_uid[4];
+
+ int64_t timecodescale;
} MatroskaMuxContext;
/** 2 bytes * 7 for EBML IDs, 7 1-byte EBML lengths, 6 1-byte uint,
@@ -1827,7 +1829,7 @@ static int mkv_write_header(AVFormatContext *s)
return ret;
pb = mkv->info.bc;
- put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
+ put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, mkv->timecodescale);
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)) {
@@ -1927,12 +1929,12 @@ 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 = 5*(1000000000/mkv->timecodescale);
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 = 1*(1000000000/mkv->timecodescale);
if (mkv->cluster_size_limit < 0)
mkv->cluster_size_limit = 32 * 1024;
}
@@ -2708,7 +2710,7 @@ static int mkv_init(struct AVFormatContext *s)
}
// ms precision is the de-facto standard timescale for mkv files
- avpriv_set_pts_info(st, 64, 1, 1000);
+ avpriv_set_pts_info(st, 64, 1, 1000000000/mkv->timecodescale);
if (st->codecpar->codec_type == AVMEDIA_TYPE_ATTACHMENT) {
if (mkv->mode == MODE_WEBM) {
@@ -2795,6 +2797,7 @@ 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" },
+ { "timecodescale", "Time code scale for all tracks in nanoseconds",
OFFSET(timecodescale), AV_OPT_TYPE_INT64, { .i64 = 1000000 }, 1,
1000000000, FLAGS },
{ NULL },
};
This, x10000000000000000!
Can we make it 1ns by default? Or maybe autodetect the highest precision
timebase of all streams and use it?
