[FFmpeg-cvslog] avformat/matroskaenc: Remove limit on the number of tracks
Andreas Rheinhardt
git at videolan.org
Tue Apr 21 08:14:27 EEST 2020
ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Wed Apr 15 04:49:46 2020 +0200| [13c12cd4702e621c7363be8f22a8b55c22a31a02] | committer: Andreas Rheinhardt
avformat/matroskaenc: Remove limit on the number of tracks
The Matroska file format has practically no limit on the number of
tracks (the current limit is 2^56 - 1); yet because they are encoded in
a variable length format in (Simple)Blocks this muxer has simply imposed
a limit on the number of tracks in order to ensure that they can always
be written on one byte in order to simplify the muxing process.
This commit removes said limit.
Also, zero is an invalid TrackNumber, so disallow this value in the
dash_track_number option.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=13c12cd4702e621c7363be8f22a8b55c22a31a02
---
libavformat/matroskaenc.c | 34 +++++++++++++---------------------
1 file changed, 13 insertions(+), 21 deletions(-)
diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index d3c6a7ea9b..116b89fb4d 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -93,6 +93,7 @@ typedef struct mkv_track {
int has_cue;
uint64_t uid;
unsigned track_num;
+ int track_num_size;
int sample_rate;
int64_t sample_rate_offset;
int64_t last_timestamp;
@@ -105,10 +106,6 @@ typedef struct mkv_track {
#define MODE_MATROSKAv2 0x01
#define MODE_WEBM 0x02
-/** Maximum number of tracks allowed in a Matroska file (with track numbers in
- * range 1 to 126 (inclusive) */
-#define MAX_TRACKS 126
-
typedef struct MatroskaMuxContext {
const AVClass *class;
int mode;
@@ -1899,9 +1896,9 @@ static int mkv_write_header(AVFormatContext *s)
return 0;
}
-static int mkv_blockgroup_size(int pkt_size)
+static int mkv_blockgroup_size(int pkt_size, int track_num_size)
{
- int size = pkt_size + 4;
+ int size = pkt_size + track_num_size + 3;
size += ebml_length_size(size);
size += 2; // EBML ID for block and block duration
size += 9; // max size of block duration incl. length field
@@ -2041,9 +2038,8 @@ static int mkv_write_block(AVFormatContext *s, AVIOContext *pb,
}
put_ebml_id(pb, blockid);
- put_ebml_length(pb, size + 4, 0);
- // this assumes stream_index is less than 126
- avio_w8(pb, 0x80 | track_number);
+ put_ebml_length(pb, size + track->track_num_size + 3, 0);
+ put_ebml_num(pb, track_number, track->track_num_size);
avio_wb16(pb, ts - mkv->cluster_pts);
avio_w8(pb, (blockid == MATROSKA_ID_SIMPLEBLOCK && keyframe) ? (1 << 7) : 0);
avio_write(pb, data + offset, size);
@@ -2106,11 +2102,12 @@ static int mkv_write_vtt_blocks(AVFormatContext *s, AVIOContext *pb, AVPacket *p
size, pkt->pts, pkt->dts, pkt->duration, avio_tell(pb),
mkv->cluster_pos, track->track_num, 1);
- blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(size));
+ blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP,
+ mkv_blockgroup_size(size, track->track_num_size));
put_ebml_id(pb, MATROSKA_ID_BLOCK);
- put_ebml_length(pb, size + 4, 0);
- avio_w8(pb, 0x80 | track->track_num); // this assumes track_num is less than 126
+ put_ebml_length(pb, size + track->track_num_size + 3, 0);
+ put_ebml_num(pb, track->track_num, track->track_num_size);
avio_wb16(pb, ts - mkv->cluster_pts);
avio_w8(pb, flags);
avio_printf(pb, "%.*s\n%.*s\n%.*s", id_size, id, settings_size, settings, pkt->size, pkt->data);
@@ -2284,7 +2281,8 @@ static int mkv_write_packet_internal(AVFormatContext *s, AVPacket *pkt, int add_
duration = mkv_write_vtt_blocks(s, pb, pkt);
} else {
ebml_master blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP,
- mkv_blockgroup_size(pkt->size));
+ mkv_blockgroup_size(pkt->size,
+ track->track_num_size));
#if FF_API_CONVERGENCE_DURATION
FF_DISABLE_DEPRECATION_WARNINGS
@@ -2646,13 +2644,7 @@ static int mkv_init(struct AVFormatContext *s)
nb_tracks++;
track->track_num = mkv->is_dash ? mkv->dash_track_number : nb_tracks;
- }
-
- if (nb_tracks > MAX_TRACKS) {
- av_log(s, AV_LOG_ERROR,
- "%u > "AV_STRINGIFY(MAX_TRACKS)" tracks (excluding attachments)"
- " not supported for muxing in Matroska\n", nb_tracks);
- return AVERROR(EINVAL);
+ track->track_num_size = ebml_num_size(track->track_num);
}
return 0;
@@ -2710,7 +2702,7 @@ static const AVOption options[] = {
{ "cluster_size_limit", "Store at most the provided amount of bytes in a cluster. ", OFFSET(cluster_size_limit), AV_OPT_TYPE_INT , { .i64 = -1 }, -1, INT_MAX, FLAGS },
{ "cluster_time_limit", "Store at most the provided number of milliseconds in a cluster.", OFFSET(cluster_time_limit), AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, FLAGS },
{ "dash", "Create a WebM file conforming to WebM DASH specification", OFFSET(is_dash), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
- { "dash_track_number", "Track number for the DASH stream", OFFSET(dash_track_number), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 127, FLAGS },
+ { "dash_track_number", "Track number for the DASH stream", OFFSET(dash_track_number), AV_OPT_TYPE_INT, { .i64 = 1 }, 1, INT_MAX, FLAGS },
{ "live", "Write files assuming it is a live stream.", OFFSET(is_live), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
{ "allow_raw_vfw", "allow RAW VFW mode", OFFSET(allow_raw_vfw), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
{ "write_crc32", "write a CRC32 element inside every Level 1 element", OFFSET(write_crc), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, FLAGS },
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