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ffmpeg/libavformat/matroskaenc.c
David Conrad 7bb83d8ddf matroskaenc: Write codec time base as default duration for video tracks. 
This isn't exactly semantically equivalent, but the field has already been
long abused to mean this, and writing it helps in determining a decent cfr
time base when transcoding from a mkv where the video codec stores none (VP8).

Originally committed as revision 23284 to svn://svn.ffmpeg.org/ffmpeg/trunk
2010-05-24 08:58:19 +00:00

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/*
* Matroska muxer
* Copyright (c) 2007 David Conrad
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "riff.h"
#include "isom.h"
#include "matroska.h"
#include "avc.h"
#include "flacenc.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/md5.h"
#include "libavcodec/xiph.h"
#include "libavcodec/mpeg4audio.h"
typedef struct ebml_master {
int64_t pos; ///< absolute offset in the file where the master's elements start
int sizebytes; ///< how many bytes were reserved for the size
} ebml_master;
typedef struct mkv_seekhead_entry {
unsigned int elementid;
uint64_t segmentpos;
} mkv_seekhead_entry;
typedef struct mkv_seekhead {
int64_t filepos;
int64_t segment_offset; ///< the file offset to the beginning of the segment
int reserved_size; ///< -1 if appending to file
int max_entries;
mkv_seekhead_entry *entries;
int num_entries;
} mkv_seekhead;
typedef struct {
uint64_t pts;
int tracknum;
int64_t cluster_pos; ///< file offset of the cluster containing the block
} mkv_cuepoint;
typedef struct {
int64_t segment_offset;
mkv_cuepoint *entries;
int num_entries;
} mkv_cues;
typedef struct {
int write_dts;
} mkv_track;
typedef struct MatroskaMuxContext {
ByteIOContext *dyn_bc;
ebml_master segment;
int64_t segment_offset;
int64_t segment_uid;
ebml_master cluster;
int64_t cluster_pos; ///< file offset of the current cluster
int64_t cluster_pts;
int64_t duration_offset;
int64_t duration;
mkv_seekhead *main_seekhead;
mkv_seekhead *cluster_seekhead;
mkv_cues *cues;
mkv_track *tracks;
struct AVMD5 *md5_ctx;
} MatroskaMuxContext;
/** 2 bytes * 3 for EBML IDs, 3 1-byte EBML lengths, 8 bytes for 64 bit
* offset, 4 bytes for target EBML ID */
#define MAX_SEEKENTRY_SIZE 21
/** per-cuepoint-track - 3 1-byte EBML IDs, 3 1-byte EBML sizes, 2
* 8-byte uint max */
#define MAX_CUETRACKPOS_SIZE 22
/** per-cuepoint - 2 1-byte EBML IDs, 2 1-byte EBML sizes, 8-byte uint max */
#define MAX_CUEPOINT_SIZE(num_tracks) 12 + MAX_CUETRACKPOS_SIZE*num_tracks
static int ebml_id_size(unsigned int id)
{
return (av_log2(id+1)-1)/7+1;
}
static void put_ebml_id(ByteIOContext *pb, unsigned int id)
{
int i = ebml_id_size(id);
while (i--)
put_byte(pb, id >> (i*8));
}
/**
* Write an EBML size meaning "unknown size".
*
* @param bytes The number of bytes the size should occupy (maximum: 8).
*/
static void put_ebml_size_unknown(ByteIOContext *pb, int bytes)
{
assert(bytes <= 8);
put_byte(pb, 0x1ff >> bytes);
while (--bytes)
put_byte(pb, 0xff);
}
/**
* Calculate how many bytes are needed to represent a given number in EBML.
*/
static int ebml_num_size(uint64_t num)
{
int bytes = 1;
while ((num+1) >> bytes*7) bytes++;
return bytes;
}
/**
* Write a number in EBML variable length format.
*
* @param bytes The number of bytes that need to be used to write the number.
* If zero, any number of bytes can be used.
*/
static void put_ebml_num(ByteIOContext *pb, uint64_t num, int bytes)
{
int i, needed_bytes = ebml_num_size(num);
// sizes larger than this are currently undefined in EBML
assert(num < (1ULL<<56)-1);
if (bytes == 0)
// don't care how many bytes are used, so use the min
bytes = needed_bytes;
// the bytes needed to write the given size would exceed the bytes
// that we need to use, so write unknown size. This shouldn't happen.
assert(bytes >= needed_bytes);
num |= 1ULL << bytes*7;
for (i = bytes - 1; i >= 0; i--)
put_byte(pb, num >> i*8);
}
static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val)
{
int i, bytes = 1;
uint64_t tmp = val;
while (tmp>>=8) bytes++;
put_ebml_id(pb, elementid);
put_ebml_num(pb, bytes, 0);
for (i = bytes - 1; i >= 0; i--)
put_byte(pb, val >> i*8);
}
static void put_ebml_float(ByteIOContext *pb, unsigned int elementid, double val)
{
put_ebml_id(pb, elementid);
put_ebml_num(pb, 8, 0);
put_be64(pb, av_dbl2int(val));
}
static void put_ebml_binary(ByteIOContext *pb, unsigned int elementid,
const uint8_t *buf, int size)
{
put_ebml_id(pb, elementid);
put_ebml_num(pb, size, 0);
put_buffer(pb, buf, size);
}
static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, const char *str)
{
put_ebml_binary(pb, elementid, str, strlen(str));
}
/**
* Writes a void element of a given size. Useful for reserving space in
* the file to be written to later.
*
* @param size The number of bytes to reserve, which must be at least 2.
*/
static void put_ebml_void(ByteIOContext *pb, uint64_t size)
{
int64_t currentpos = url_ftell(pb);
assert(size >= 2);
put_ebml_id(pb, EBML_ID_VOID);
// we need to subtract the length needed to store the size from the
// size we need to reserve so 2 cases, we use 8 bytes to store the
// size if possible, 1 byte otherwise
if (size < 10)
put_ebml_num(pb, size-1, 0);
else
put_ebml_num(pb, size-9, 8);
while(url_ftell(pb) < currentpos + size)
put_byte(pb, 0);
}
static ebml_master start_ebml_master(ByteIOContext *pb, unsigned int elementid, uint64_t expectedsize)
{
int bytes = expectedsize ? ebml_num_size(expectedsize) : 8;
put_ebml_id(pb, elementid);
put_ebml_size_unknown(pb, bytes);
return (ebml_master){ url_ftell(pb), bytes };
}
static void end_ebml_master(ByteIOContext *pb, ebml_master master)
{
int64_t pos = url_ftell(pb);
if (url_fseek(pb, master.pos - master.sizebytes, SEEK_SET) < 0)
return;
put_ebml_num(pb, pos - master.pos, master.sizebytes);
url_fseek(pb, pos, SEEK_SET);
}
static void put_xiph_size(ByteIOContext *pb, int size)
{
int i;
for (i = 0; i < size / 255; i++)
put_byte(pb, 255);
put_byte(pb, size % 255);
}
/**
* Initialize a mkv_seekhead element to be ready to index level 1 Matroska
* elements. If a maximum number of elements is specified, enough space
* will be reserved at the current file location to write a seek head of
* that size.
*
* @param segment_offset The absolute offset to the position in the file
* where the segment begins.
* @param numelements The maximum number of elements that will be indexed
* by this seek head, 0 if unlimited.
*/
static mkv_seekhead * mkv_start_seekhead(ByteIOContext *pb, int64_t segment_offset, int numelements)
{
mkv_seekhead *new_seekhead = av_mallocz(sizeof(mkv_seekhead));
if (new_seekhead == NULL)
return NULL;
new_seekhead->segment_offset = segment_offset;
if (numelements > 0) {
new_seekhead->filepos = url_ftell(pb);
// 21 bytes max for a seek entry, 10 bytes max for the SeekHead ID
// and size, and 3 bytes to guarantee that an EBML void element
// will fit afterwards
new_seekhead->reserved_size = numelements * MAX_SEEKENTRY_SIZE + 13;
new_seekhead->max_entries = numelements;
put_ebml_void(pb, new_seekhead->reserved_size);
}
return new_seekhead;
}
static int mkv_add_seekhead_entry(mkv_seekhead *seekhead, unsigned int elementid, uint64_t filepos)
{
mkv_seekhead_entry *entries = seekhead->entries;
// don't store more elements than we reserved space for
if (seekhead->max_entries > 0 && seekhead->max_entries <= seekhead->num_entries)
return -1;
entries = av_realloc(entries, (seekhead->num_entries + 1) * sizeof(mkv_seekhead_entry));
if (entries == NULL)
return AVERROR(ENOMEM);
entries[seekhead->num_entries ].elementid = elementid;
entries[seekhead->num_entries++].segmentpos = filepos - seekhead->segment_offset;
seekhead->entries = entries;
return 0;
}
/**
* Write the seek head to the file and free it. If a maximum number of
* elements was specified to mkv_start_seekhead(), the seek head will
* be written at the location reserved for it. Otherwise, it is written
* at the current location in the file.
*
* @return The file offset where the seekhead was written,
* -1 if an error occurred.
*/
static int64_t mkv_write_seekhead(ByteIOContext *pb, mkv_seekhead *seekhead)
{
ebml_master metaseek, seekentry;
int64_t currentpos;
int i;
currentpos = url_ftell(pb);
if (seekhead->reserved_size > 0)
if (url_fseek(pb, seekhead->filepos, SEEK_SET) < 0)
return -1;
metaseek = start_ebml_master(pb, MATROSKA_ID_SEEKHEAD, seekhead->reserved_size);
for (i = 0; i < seekhead->num_entries; i++) {
mkv_seekhead_entry *entry = &seekhead->entries[i];
seekentry = start_ebml_master(pb, MATROSKA_ID_SEEKENTRY, MAX_SEEKENTRY_SIZE);
put_ebml_id(pb, MATROSKA_ID_SEEKID);
put_ebml_num(pb, ebml_id_size(entry->elementid), 0);
put_ebml_id(pb, entry->elementid);
put_ebml_uint(pb, MATROSKA_ID_SEEKPOSITION, entry->segmentpos);
end_ebml_master(pb, seekentry);
}
end_ebml_master(pb, metaseek);
if (seekhead->reserved_size > 0) {
uint64_t remaining = seekhead->filepos + seekhead->reserved_size - url_ftell(pb);
put_ebml_void(pb, remaining);
url_fseek(pb, currentpos, SEEK_SET);
currentpos = seekhead->filepos;
}
av_free(seekhead->entries);
av_free(seekhead);
return currentpos;
}
static mkv_cues * mkv_start_cues(int64_t segment_offset)
{
mkv_cues *cues = av_mallocz(sizeof(mkv_cues));
if (cues == NULL)
return NULL;
cues->segment_offset = segment_offset;
return cues;
}
static int mkv_add_cuepoint(mkv_cues *cues, int stream, int64_t ts, int64_t cluster_pos)
{
mkv_cuepoint *entries = cues->entries;
entries = av_realloc(entries, (cues->num_entries + 1) * sizeof(mkv_cuepoint));
if (entries == NULL)
return AVERROR(ENOMEM);
if (ts < 0)
return 0;
entries[cues->num_entries ].pts = ts;
entries[cues->num_entries ].tracknum = stream + 1;
entries[cues->num_entries++].cluster_pos = cluster_pos - cues->segment_offset;
cues->entries = entries;
return 0;
}
static int64_t mkv_write_cues(ByteIOContext *pb, mkv_cues *cues, int num_tracks)
{
ebml_master cues_element;
int64_t currentpos;
int i, j;
currentpos = url_ftell(pb);
cues_element = start_ebml_master(pb, MATROSKA_ID_CUES, 0);
for (i = 0; i < cues->num_entries; i++) {
ebml_master cuepoint, track_positions;
mkv_cuepoint *entry = &cues->entries[i];
uint64_t pts = entry->pts;
cuepoint = start_ebml_master(pb, MATROSKA_ID_POINTENTRY, MAX_CUEPOINT_SIZE(num_tracks));
put_ebml_uint(pb, MATROSKA_ID_CUETIME, pts);
// put all the entries from different tracks that have the exact same
// timestamp into the same CuePoint
for (j = 0; j < cues->num_entries - i && entry[j].pts == pts; j++) {
track_positions = start_ebml_master(pb, MATROSKA_ID_CUETRACKPOSITION, MAX_CUETRACKPOS_SIZE);
put_ebml_uint(pb, MATROSKA_ID_CUETRACK , entry[j].tracknum );
put_ebml_uint(pb, MATROSKA_ID_CUECLUSTERPOSITION, entry[j].cluster_pos);
end_ebml_master(pb, track_positions);
}
i += j - 1;
end_ebml_master(pb, cuepoint);
}
end_ebml_master(pb, cues_element);
av_free(cues->entries);
av_free(cues);
return currentpos;
}
static int put_xiph_codecpriv(AVFormatContext *s, ByteIOContext *pb, AVCodecContext *codec)
{
uint8_t *header_start[3];
int header_len[3];
int first_header_size;
int j;
if (codec->codec_id == CODEC_ID_VORBIS)
first_header_size = 30;
else
first_header_size = 42;
if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
first_header_size, header_start, header_len) < 0) {
av_log(s, AV_LOG_ERROR, "Extradata corrupt.\n");
return -1;
}
put_byte(pb, 2); // number packets - 1
for (j = 0; j < 2; j++) {
put_xiph_size(pb, header_len[j]);
}
for (j = 0; j < 3; j++)
put_buffer(pb, header_start[j], header_len[j]);
return 0;
}
static void get_aac_sample_rates(AVFormatContext *s, AVCodecContext *codec, int *sample_rate, int *output_sample_rate)
{
int sri;
if (codec->extradata_size < 2) {
av_log(s, AV_LOG_WARNING, "No AAC extradata, unable to determine samplerate.\n");
return;
}
sri = ((codec->extradata[0] << 1) & 0xE) | (codec->extradata[1] >> 7);
if (sri > 12) {
av_log(s, AV_LOG_WARNING, "AAC samplerate index out of bounds\n");
return;
}
*sample_rate = ff_mpeg4audio_sample_rates[sri];
// if sbr, get output sample rate as well
if (codec->extradata_size == 5) {
sri = (codec->extradata[4] >> 3) & 0xF;
if (sri > 12) {
av_log(s, AV_LOG_WARNING, "AAC output samplerate index out of bounds\n");
return;
}
*output_sample_rate = ff_mpeg4audio_sample_rates[sri];
}
}
static int mkv_write_codecprivate(AVFormatContext *s, ByteIOContext *pb, AVCodecContext *codec, int native_id, int qt_id)
{
ByteIOContext *dyn_cp;
uint8_t *codecpriv;
int ret, codecpriv_size;
ret = url_open_dyn_buf(&dyn_cp);
if(ret < 0)
return ret;
if (native_id) {
if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA)
ret = put_xiph_codecpriv(s, dyn_cp, codec);
else if (codec->codec_id == CODEC_ID_FLAC)
ret = ff_flac_write_header(dyn_cp, codec, 1);
else if (codec->codec_id == CODEC_ID_H264)
ret = ff_isom_write_avcc(dyn_cp, codec->extradata, codec->extradata_size);
else if (codec->extradata_size)
put_buffer(dyn_cp, codec->extradata, codec->extradata_size);
} else if (codec->codec_type == AVMEDIA_TYPE_VIDEO) {
if (qt_id) {
if (!codec->codec_tag)
codec->codec_tag = ff_codec_get_tag(codec_movvideo_tags, codec->codec_id);
if (codec->extradata_size)
put_buffer(dyn_cp, codec->extradata, codec->extradata_size);
} else {
if (!codec->codec_tag)
codec->codec_tag = ff_codec_get_tag(ff_codec_bmp_tags, codec->codec_id);
if (!codec->codec_tag) {
av_log(s, AV_LOG_ERROR, "No bmp codec ID found.\n");
ret = -1;
}
ff_put_bmp_header(dyn_cp, codec, ff_codec_bmp_tags, 0);
}
} else if (codec->codec_type == AVMEDIA_TYPE_AUDIO) {
unsigned int tag;
tag = ff_codec_get_tag(ff_codec_wav_tags, codec->codec_id);
if (!tag) {
av_log(s, AV_LOG_ERROR, "No wav codec ID found.\n");
ret = -1;
}
if (!codec->codec_tag)
codec->codec_tag = tag;
ff_put_wav_header(dyn_cp, codec);
}
codecpriv_size = url_close_dyn_buf(dyn_cp, &codecpriv);
if (codecpriv_size)
put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codecpriv, codecpriv_size);
av_free(codecpriv);
return ret;
}
static int mkv_write_tracks(AVFormatContext *s)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = s->pb;
ebml_master tracks;
int i, j, ret;
ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, url_ftell(pb));
if (ret < 0) return ret;
tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS, 0);
for (i = 0; i < s->nb_streams; i++) {
AVStream *st = s->streams[i];
AVCodecContext *codec = st->codec;
ebml_master subinfo, track;
int native_id = 0;
int qt_id = 0;
int bit_depth = av_get_bits_per_sample(codec->codec_id);
int sample_rate = codec->sample_rate;
int output_sample_rate = 0;
AVMetadataTag *tag;
if (!bit_depth)
bit_depth = av_get_bits_per_sample_format(codec->sample_fmt);
if (codec->codec_id == CODEC_ID_AAC)
get_aac_sample_rates(s, codec, &sample_rate, &output_sample_rate);
track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY, 0);
put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER , i + 1);
put_ebml_uint (pb, MATROSKA_ID_TRACKUID , i + 1);
put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0); // no lacing (yet)
if ((tag = av_metadata_get(st->metadata, "title", NULL, 0)))
put_ebml_string(pb, MATROSKA_ID_TRACKNAME, tag->value);
tag = av_metadata_get(st->metadata, "language", NULL, 0);
put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, tag ? tag->value:"und");
if (st->disposition)
put_ebml_uint(pb, MATROSKA_ID_TRACKFLAGDEFAULT, !!(st->disposition & AV_DISPOSITION_DEFAULT));
// look for a codec ID string specific to mkv to use,
// if none are found, use AVI codes
for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
if (ff_mkv_codec_tags[j].id == codec->codec_id) {
put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
native_id = 1;
break;
}
}
switch (codec->codec_type) {
case AVMEDIA_TYPE_VIDEO:
put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
put_ebml_uint(pb, MATROSKA_ID_TRACKDEFAULTDURATION, av_q2d(codec->time_base)*1E9);
if (!native_id &&
ff_codec_get_tag(codec_movvideo_tags, codec->codec_id) &&
(!ff_codec_get_tag(ff_codec_bmp_tags, codec->codec_id)
|| codec->codec_id == CODEC_ID_SVQ1
|| codec->codec_id == CODEC_ID_SVQ3
|| codec->codec_id == CODEC_ID_CINEPAK))
qt_id = 1;
if (qt_id)
put_ebml_string(pb, MATROSKA_ID_CODECID, "V_QUICKTIME");
else if (!native_id) {
// if there is no mkv-specific codec ID, use VFW mode
put_ebml_string(pb, MATROSKA_ID_CODECID, "V_MS/VFW/FOURCC");
mkv->tracks[i].write_dts = 1;
}
subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO, 0);
// XXX: interlace flag?
put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
if (st->sample_aspect_ratio.num) {
int d_width = codec->width*av_q2d(st->sample_aspect_ratio);
put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , d_width);
put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, codec->height);
}
end_ebml_master(pb, subinfo);
break;
case AVMEDIA_TYPE_AUDIO:
put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
if (!native_id)
// no mkv-specific ID, use ACM mode
put_ebml_string(pb, MATROSKA_ID_CODECID, "A_MS/ACM");
subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO, 0);
put_ebml_uint (pb, MATROSKA_ID_AUDIOCHANNELS , codec->channels);
put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
if (output_sample_rate)
put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
if (bit_depth)
put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
end_ebml_master(pb, subinfo);
break;
case AVMEDIA_TYPE_SUBTITLE:
put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_SUBTITLE);
break;
default:
av_log(s, AV_LOG_ERROR, "Only audio, video, and subtitles are supported for Matroska.");
break;
}
ret = mkv_write_codecprivate(s, pb, codec, native_id, qt_id);
if (ret < 0) return ret;
end_ebml_master(pb, track);
// ms precision is the de-facto standard timescale for mkv files
av_set_pts_info(st, 64, 1, 1000);
}
end_ebml_master(pb, tracks);
return 0;
}
static int mkv_write_chapters(AVFormatContext *s)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = s->pb;
ebml_master chapters, editionentry;
AVRational scale = {1, 1E9};
int i, ret;
if (!s->nb_chapters)
return 0;
ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CHAPTERS, url_ftell(pb));
if (ret < 0) return ret;
chapters = start_ebml_master(pb, MATROSKA_ID_CHAPTERS , 0);
editionentry = start_ebml_master(pb, MATROSKA_ID_EDITIONENTRY, 0);
put_ebml_uint(pb, MATROSKA_ID_EDITIONFLAGDEFAULT, 1);
put_ebml_uint(pb, MATROSKA_ID_EDITIONFLAGHIDDEN , 0);
for (i = 0; i < s->nb_chapters; i++) {
ebml_master chapteratom, chapterdisplay;
AVChapter *c = s->chapters[i];
AVMetadataTag *t = NULL;
chapteratom = start_ebml_master(pb, MATROSKA_ID_CHAPTERATOM, 0);
put_ebml_uint(pb, MATROSKA_ID_CHAPTERUID, c->id);
put_ebml_uint(pb, MATROSKA_ID_CHAPTERTIMESTART,
av_rescale_q(c->start, c->time_base, scale));
put_ebml_uint(pb, MATROSKA_ID_CHAPTERTIMEEND,
av_rescale_q(c->end, c->time_base, scale));
put_ebml_uint(pb, MATROSKA_ID_CHAPTERFLAGHIDDEN , 0);
put_ebml_uint(pb, MATROSKA_ID_CHAPTERFLAGENABLED, 1);
if ((t = av_metadata_get(c->metadata, "title", NULL, 0))) {
chapterdisplay = start_ebml_master(pb, MATROSKA_ID_CHAPTERDISPLAY, 0);
put_ebml_string(pb, MATROSKA_ID_CHAPSTRING, t->value);
put_ebml_string(pb, MATROSKA_ID_CHAPLANG , "und");
end_ebml_master(pb, chapterdisplay);
}
end_ebml_master(pb, chapteratom);
}
end_ebml_master(pb, editionentry);
end_ebml_master(pb, chapters);
return 0;
}
static int mkv_write_header(AVFormatContext *s)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = s->pb;
ebml_master ebml_header, segment_info;
AVMetadataTag *tag;
int ret;
mkv->md5_ctx = av_mallocz(av_md5_size);
av_md5_init(mkv->md5_ctx);
mkv->tracks = av_mallocz(s->nb_streams * sizeof(*mkv->tracks));
ebml_header = start_ebml_master(pb, EBML_ID_HEADER, 0);
put_ebml_uint (pb, EBML_ID_EBMLVERSION , 1);
put_ebml_uint (pb, EBML_ID_EBMLREADVERSION , 1);
put_ebml_uint (pb, EBML_ID_EBMLMAXIDLENGTH , 4);
put_ebml_uint (pb, EBML_ID_EBMLMAXSIZELENGTH , 8);
put_ebml_string (pb, EBML_ID_DOCTYPE , "matroska");
put_ebml_uint (pb, EBML_ID_DOCTYPEVERSION , 2);
put_ebml_uint (pb, EBML_ID_DOCTYPEREADVERSION , 2);
end_ebml_master(pb, ebml_header);
mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT, 0);
mkv->segment_offset = url_ftell(pb);
// we write 2 seek heads - one at the end of the file to point to each
// cluster, and one at the beginning to point to all other level one
// elements (including the seek head at the end of the file), which
// isn't more than 10 elements if we only write one of each other
// currently defined level 1 element
mkv->main_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 10);
mkv->cluster_seekhead = mkv_start_seekhead(pb, mkv->segment_offset, 0);
if (mkv->main_seekhead == NULL || mkv->cluster_seekhead == NULL)
return AVERROR(ENOMEM);
ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_INFO, url_ftell(pb));
if (ret < 0) return ret;
segment_info = start_ebml_master(pb, MATROSKA_ID_INFO, 0);
put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
if ((tag = av_metadata_get(s->metadata, "title", NULL, 0)))
put_ebml_string(pb, MATROSKA_ID_TITLE, tag->value);
if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
put_ebml_string(pb, MATROSKA_ID_MUXINGAPP , LIBAVFORMAT_IDENT);
put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
// reserve space to write the segment UID later
mkv->segment_uid = url_ftell(pb);
put_ebml_void(pb, 19);
}
// reserve space for the duration
mkv->duration = 0;
mkv->duration_offset = url_ftell(pb);
put_ebml_void(pb, 11); // assumes double-precision float to be written
end_ebml_master(pb, segment_info);
ret = mkv_write_tracks(s);
if (ret < 0) return ret;
ret = mkv_write_chapters(s);
if (ret < 0) return ret;
if (url_is_streamed(s->pb))
mkv_write_seekhead(pb, mkv->main_seekhead);
mkv->cues = mkv_start_cues(mkv->segment_offset);
if (mkv->cues == NULL)
return AVERROR(ENOMEM);
put_flush_packet(pb);
return 0;
}
static int mkv_blockgroup_size(int pkt_size)
{
int size = pkt_size + 4;
size += ebml_num_size(size);
size += 2; // EBML ID for block and block duration
size += 8; // max size of block duration
size += ebml_num_size(size);
size += 1; // blockgroup EBML ID
return size;
}
static int ass_get_duration(const uint8_t *p)
{
int sh, sm, ss, sc, eh, em, es, ec;
uint64_t start, end;
if (sscanf(p, "%*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d",
&sh, &sm, &ss, &sc, &eh, &em, &es, &ec) != 8)
return 0;
start = 3600000*sh + 60000*sm + 1000*ss + 10*sc;
end = 3600000*eh + 60000*em + 1000*es + 10*ec;
return end - start;
}
static int mkv_write_ass_blocks(AVFormatContext *s, ByteIOContext *pb, AVPacket *pkt)
{
MatroskaMuxContext *mkv = s->priv_data;
int i, layer = 0, max_duration = 0, size, line_size, data_size = pkt->size;
uint8_t *start, *end, *data = pkt->data;
ebml_master blockgroup;
char buffer[2048];
while (data_size) {
int duration = ass_get_duration(data);
max_duration = FFMAX(duration, max_duration);
end = memchr(data, '\n', data_size);
size = line_size = end ? end-data+1 : data_size;
size -= end ? (end[-1]=='\r')+1 : 0;
start = data;
for (i=0; i<3; i++, start++)
if (!(start = memchr(start, ',', size-(start-data))))
return max_duration;
size -= start - data;
sscanf(data, "Dialogue: %d,", &layer);
i = snprintf(buffer, sizeof(buffer), "%"PRId64",%d,",
s->streams[pkt->stream_index]->nb_frames++, layer);
size = FFMIN(i+size, sizeof(buffer));
memcpy(buffer+i, start, size-i);
av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size %d, "
"pts %" PRId64 ", duration %d\n",
url_ftell(pb), size, pkt->pts, duration);
blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(size));
put_ebml_id(pb, MATROSKA_ID_BLOCK);
put_ebml_num(pb, size+4, 0);
put_byte(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126
put_be16(pb, pkt->pts - mkv->cluster_pts);
put_byte(pb, 0);
put_buffer(pb, buffer, size);
put_ebml_uint(pb, MATROSKA_ID_BLOCKDURATION, duration);
end_ebml_master(pb, blockgroup);
data += line_size;
data_size -= line_size;
}
return max_duration;
}
static void mkv_write_block(AVFormatContext *s, ByteIOContext *pb,
unsigned int blockid, AVPacket *pkt, int flags)
{
MatroskaMuxContext *mkv = s->priv_data;
AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
uint8_t *data = NULL;
int size = pkt->size;
int64_t ts = mkv->tracks[pkt->stream_index].write_dts ? pkt->dts : pkt->pts;
av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size %d, "
"pts %" PRId64 ", dts %" PRId64 ", duration %d, flags %d\n",
url_ftell(pb), pkt->size, pkt->pts, pkt->dts, pkt->duration, flags);
if (codec->codec_id == CODEC_ID_H264 && codec->extradata_size > 0 &&
(AV_RB24(codec->extradata) == 1 || AV_RB32(codec->extradata) == 1))
ff_avc_parse_nal_units_buf(pkt->data, &data, &size);
else
data = pkt->data;
put_ebml_id(pb, blockid);
put_ebml_num(pb, size+4, 0);
put_byte(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126
put_be16(pb, ts - mkv->cluster_pts);
put_byte(pb, flags);
put_buffer(pb, data, size);
if (data != pkt->data)
av_free(data);
}
static void mkv_flush_dynbuf(AVFormatContext *s)
{
MatroskaMuxContext *mkv = s->priv_data;
int bufsize;
uint8_t *dyn_buf;
if (!mkv->dyn_bc)
return;
bufsize = url_close_dyn_buf(mkv->dyn_bc, &dyn_buf);
put_buffer(s->pb, dyn_buf, bufsize);
av_free(dyn_buf);
mkv->dyn_bc = NULL;
}
static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = s->pb;
AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
int keyframe = !!(pkt->flags & AV_PKT_FLAG_KEY);
int duration = pkt->duration;
int ret;
int64_t ts = mkv->tracks[pkt->stream_index].write_dts ? pkt->dts : pkt->pts;
if (ts == AV_NOPTS_VALUE) {
av_log(s, AV_LOG_ERROR, "Can't write packet with unknown timestamp\n");
return AVERROR(EINVAL);
}
if (url_is_streamed(s->pb)) {
if (!mkv->dyn_bc)
url_open_dyn_buf(&mkv->dyn_bc);
pb = mkv->dyn_bc;
}
if (!mkv->cluster_pos) {
ret = mkv_add_seekhead_entry(mkv->cluster_seekhead, MATROSKA_ID_CLUSTER, url_ftell(pb));
if (ret < 0) return ret;
mkv->cluster_pos = url_ftell(s->pb);
mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, FFMAX(0, ts));
mkv->cluster_pts = FFMAX(0, ts);
av_md5_update(mkv->md5_ctx, pkt->data, FFMIN(200, pkt->size));
}
if (codec->codec_type != AVMEDIA_TYPE_SUBTITLE) {
mkv_write_block(s, pb, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe << 7);
} else if (codec->codec_id == CODEC_ID_SSA) {
duration = mkv_write_ass_blocks(s, pb, pkt);
} else {
ebml_master blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(pkt->size));
duration = pkt->convergence_duration;
mkv_write_block(s, pb, MATROSKA_ID_BLOCK, pkt, 0);
put_ebml_uint(pb, MATROSKA_ID_BLOCKDURATION, duration);
end_ebml_master(pb, blockgroup);
}
if (codec->codec_type == AVMEDIA_TYPE_VIDEO && keyframe) {
ret = mkv_add_cuepoint(mkv->cues, pkt->stream_index, ts, mkv->cluster_pos);
if (ret < 0) return ret;
}
// start a new cluster every 5 MB or 5 sec, or 32k / 1 sec for streaming
if ((url_is_streamed(s->pb) && (url_ftell(pb) > 32*1024 || ts > mkv->cluster_pts + 1000))
|| url_ftell(pb) > mkv->cluster_pos + 5*1024*1024 || ts > mkv->cluster_pts + 5000) {
av_log(s, AV_LOG_DEBUG, "Starting new cluster at offset %" PRIu64
" bytes, pts %" PRIu64 "\n", url_ftell(pb), ts);
end_ebml_master(pb, mkv->cluster);
mkv->cluster_pos = 0;
if (mkv->dyn_bc)
mkv_flush_dynbuf(s);
}
mkv->duration = FFMAX(mkv->duration, ts + duration);
return 0;
}
static int mkv_write_trailer(AVFormatContext *s)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = s->pb;
int64_t currentpos, second_seekhead, cuespos;
int ret;
if (mkv->dyn_bc) {
end_ebml_master(mkv->dyn_bc, mkv->cluster);
mkv_flush_dynbuf(s);
} else if (mkv->cluster_pos) {
end_ebml_master(pb, mkv->cluster);
}
if (!url_is_streamed(pb)) {
cuespos = mkv_write_cues(pb, mkv->cues, s->nb_streams);
second_seekhead = mkv_write_seekhead(pb, mkv->cluster_seekhead);
ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CUES , cuespos);
if (ret < 0) return ret;
if (second_seekhead >= 0) {
ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_SEEKHEAD, second_seekhead);
if (ret < 0) return ret;
}
mkv_write_seekhead(pb, mkv->main_seekhead);
// update the duration
av_log(s, AV_LOG_DEBUG, "end duration = %" PRIu64 "\n", mkv->duration);
currentpos = url_ftell(pb);
url_fseek(pb, mkv->duration_offset, SEEK_SET);
put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
// write the md5sum of some frames as the segment UID
if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
uint8_t segment_uid[16];
av_md5_final(mkv->md5_ctx, segment_uid);
url_fseek(pb, mkv->segment_uid, SEEK_SET);
put_ebml_binary(pb, MATROSKA_ID_SEGMENTUID, segment_uid, 16);
}
url_fseek(pb, currentpos, SEEK_SET);
}
end_ebml_master(pb, mkv->segment);
av_free(mkv->md5_ctx);
av_free(mkv->tracks);
put_flush_packet(pb);
return 0;
}
AVOutputFormat matroska_muxer = {
"matroska",
NULL_IF_CONFIG_SMALL("Matroska file format"),
"video/x-matroska",
"mkv",
sizeof(MatroskaMuxContext),
CODEC_ID_MP2,
CODEC_ID_MPEG4,
mkv_write_header,
mkv_write_packet,
mkv_write_trailer,
.flags = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS,
.codec_tag = (const AVCodecTag* const []){ff_codec_bmp_tags, ff_codec_wav_tags, 0},
.subtitle_codec = CODEC_ID_TEXT,
};
AVOutputFormat matroska_audio_muxer = {
"matroska",
NULL_IF_CONFIG_SMALL("Matroska file format"),
"audio/x-matroska",
"mka",
sizeof(MatroskaMuxContext),
CODEC_ID_MP2,
CODEC_ID_NONE,
mkv_write_header,
mkv_write_packet,
mkv_write_trailer,
.flags = AVFMT_GLOBALHEADER,
.codec_tag = (const AVCodecTag* const []){ff_codec_wav_tags, 0},
};
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