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ffmpeg / libavformat / matroskaenc.c @ 02f487fc

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/*
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 * Matroska file muxer
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 * Copyright (c) 2007 David Conrad
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "avformat.h"
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#include "riff.h"
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#include "xiph.h"
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#include "matroska.h"
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typedef struct MatroskaMuxContext {
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    offset_t    segment;
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    offset_t    cluster;
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    uint64_t    cluster_pts;
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    offset_t    duration_offset;
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    uint64_t    duration;
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} MatroskaMuxContext;
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static void put_ebml_id(ByteIOContext *pb, unsigned int id)
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{
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    if (id >= 0x3fffff)
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        put_byte(pb, id >> 24);
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    if (id >= 0x7fff)
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        put_byte(pb, id >> 16);
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    if (id >= 0xff)
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        put_byte(pb, id >> 8);
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    put_byte(pb, id);
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}
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// XXX: test this thoroughly and get rid of minbytes hack (currently needed to
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// use up all of the space reserved in start_ebml_master)
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static void put_ebml_size(ByteIOContext *pb, uint64_t size, int minbytes)
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{
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    int bytes = minbytes;
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    // sizes larger than this are currently undefined in EBML
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    // so write "unknown" size
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    size = FFMIN(size, (1ULL<<56)-1);
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    while (size >> (bytes*7 + 7)) bytes++;
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    put_byte(pb, (0x80 >> bytes) | (size >> bytes*8));
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    for (bytes -= 1; bytes >= 0; bytes--)
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        put_byte(pb, size >> bytes*8);
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}
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static void put_ebml_uint(ByteIOContext *pb, unsigned int elementid, uint64_t val)
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{
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    int bytes = 1;
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    while (val >> bytes*8) bytes++;
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    put_ebml_id(pb, elementid);
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    put_ebml_size(pb, bytes, 0);
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    for (bytes -= 1; bytes >= 0; bytes--)
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        put_byte(pb, val >> bytes*8);
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}
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static void put_ebml_float(ByteIOContext *pb, unsigned int elementid, double val)
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{
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    // XXX: single-precision floats?
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    put_ebml_id(pb, elementid);
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    put_ebml_size(pb, 8, 0);
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    put_be64(pb, av_dbl2int(val));
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}
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static void put_ebml_binary(ByteIOContext *pb, unsigned int elementid,
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                            const uint8_t *buf, int size)
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{
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    put_ebml_id(pb, elementid);
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    put_ebml_size(pb, size, 0);
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    put_buffer(pb, buf, size);
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}
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static void put_ebml_string(ByteIOContext *pb, unsigned int elementid, const char *str)
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{
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    put_ebml_binary(pb, elementid, str, strlen(str));
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}
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// this reserves exactly the amount of space specified by size, which must be at least 2
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static void put_ebml_void(ByteIOContext *pb, uint64_t size)
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{
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    offset_t currentpos = url_ftell(pb);
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    if (size < 2)
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        return;
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    put_ebml_id(pb, EBML_ID_VOID);
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    // we need to subtract the length needed to store the size from the size we need to reserve
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    // so 2 cases, we use 8 bytes to store the size if possible, 1 byte otherwise
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    if (size < 10)
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        put_ebml_size(pb, size-1, 0);
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    else
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        put_ebml_size(pb, size-9, 7);
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    url_fseek(pb, currentpos + size, SEEK_SET);
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}
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static offset_t start_ebml_master(ByteIOContext *pb, unsigned int elementid)
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{
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    put_ebml_id(pb, elementid);
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    // XXX: this always reserves the maximum needed space to store any size value
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    // we should be smarter (additional parameter for expected size?)
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    put_ebml_size(pb, (1ULL<<56)-1, 0);     // largest unknown size
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    return url_ftell(pb);
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}
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static void end_ebml_master(ByteIOContext *pb, offset_t start)
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{
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    offset_t pos = url_ftell(pb);
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    url_fseek(pb, start - 8, SEEK_SET);
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    put_ebml_size(pb, pos - start, 7);
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    url_fseek(pb, pos, SEEK_SET);
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}
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static int mkv_write_header(AVFormatContext *s)
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{
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    MatroskaMuxContext *mkv = s->priv_data;
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    ByteIOContext *pb = &s->pb;
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    offset_t ebml_header, segment_info, tracks;
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    int i, j, k;
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    ebml_header = start_ebml_master(pb, EBML_ID_HEADER);
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    put_ebml_uint   (pb, EBML_ID_EBMLVERSION        ,           1);
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    put_ebml_uint   (pb, EBML_ID_EBMLREADVERSION    ,           1);
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    put_ebml_uint   (pb, EBML_ID_EBMLMAXIDLENGTH    ,           4);
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    put_ebml_uint   (pb, EBML_ID_EBMLMAXSIZELENGTH  ,           8);
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    put_ebml_string (pb, EBML_ID_DOCTYPE            ,  "matroska");
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    put_ebml_uint   (pb, EBML_ID_DOCTYPEVERSION     ,           2);
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    put_ebml_uint   (pb, EBML_ID_DOCTYPEREADVERSION ,           2);
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    end_ebml_master(pb, ebml_header);
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    mkv->segment = start_ebml_master(pb, MATROSKA_ID_SEGMENT);
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    segment_info = start_ebml_master(pb, MATROSKA_ID_INFO);
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    put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
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    if (strlen(s->title))
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        put_ebml_string(pb, MATROSKA_ID_TITLE, s->title);
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    if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
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        put_ebml_string(pb, MATROSKA_ID_MUXINGAPP, LIBAVFORMAT_IDENT);
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        // XXX: both are required; something better for writing app?
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        put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
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    }
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    // XXX: segment UID
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    // reserve space for the duration
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    mkv->duration = 0;
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    mkv->duration_offset = url_ftell(pb);
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    put_ebml_void(pb, 11);                  // assumes double-precision float to be written
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    end_ebml_master(pb, segment_info);
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    tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS);
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    for (i = 0; i < s->nb_streams; i++) {
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        AVStream *st = s->streams[i];
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        AVCodecContext *codec = st->codec;
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        offset_t subinfo, track;
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        int native_id = 0;
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        track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY);
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        put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER     , i + 1);
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        put_ebml_uint (pb, MATROSKA_ID_TRACKUID        , i + 1);
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        put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0);    // no lacing (yet)
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        if (st->language[0])
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            put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, st->language);
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        // look for a codec id string specific to mkv to use, if none are found, use AVI codes
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        for (j = 0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++) {
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            if (ff_mkv_codec_tags[j].id == codec->codec_id) {
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                put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
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                native_id = 1;
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                break;
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            }
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        }
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        // XXX: CodecPrivate for vorbis, theora, aac, native mpeg4, ...
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        if (native_id) {
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            offset_t codecprivate;
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            if (codec->codec_id == CODEC_ID_VORBIS || codec->codec_id == CODEC_ID_THEORA) {
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                uint8_t *header_start[3];
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                int header_len[3];
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                int first_header_size;
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                if (codec->codec_id == CODEC_ID_VORBIS)
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                    first_header_size = 30;
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                else
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                    first_header_size = 42;
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                if (ff_split_xiph_headers(codec->extradata, codec->extradata_size,
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                                          first_header_size, header_start, header_len) < 0) {
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                    av_log(s, AV_LOG_ERROR, "Extradata corrupt.\n");
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                    return -1;
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                }
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                codecprivate = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
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                put_byte(pb, 2);                    // number packets - 1
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                for (j = 0; j < 2; j++) {
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                    for (k = 0; k < header_len[j] / 255; k++)
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                        put_byte(pb, 255);
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                    put_byte(pb, header_len[j] % 255);
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                }
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                for (j = 0; j < 3; j++)
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                    put_buffer(pb, header_start[j], header_len[j]);
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                end_ebml_master(pb, codecprivate);
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            } else {
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                put_ebml_binary(pb, MATROSKA_ID_CODECPRIVATE, codec->extradata, codec->extradata_size);
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            }
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        }
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        switch (codec->codec_type) {
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            case CODEC_TYPE_VIDEO:
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                put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
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                if (!native_id) {
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                    offset_t bmp_header;
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                    // if there is no mkv-specific codec id, use VFW mode
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                    if (!codec->codec_tag)
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                        codec->codec_tag = codec_get_tag(codec_bmp_tags, codec->codec_id);
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                    put_ebml_string(pb, MATROSKA_ID_CODECID, MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC);
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                    // XXX: codec private isn't a master; is there a better way to re-use put_bmp_header?
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                    bmp_header = start_ebml_master(pb, MATROSKA_ID_CODECPRIVATE);
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                    put_bmp_header(pb, codec, codec_bmp_tags, 0);
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                    end_ebml_master(pb, bmp_header);
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                }
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                subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO);
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                // XXX: interlace flag?
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                put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
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                put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
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                // XXX: display width/height
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                end_ebml_master(pb, subinfo);
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                break;
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            case CODEC_TYPE_AUDIO:
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                put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
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                // XXX: A_MS/ACM
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                subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO);
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                put_ebml_uint  (pb, MATROSKA_ID_AUDIOCHANNELS    , codec->channels);
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                put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, codec->sample_rate);
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                // XXX: output sample freq (for sbr) and bitdepth (for pcm)
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                end_ebml_master(pb, subinfo);
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                break;
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            default:
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                av_log(s, AV_LOG_ERROR, "Only audio and video are supported for Matroska.");
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                break;
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        }
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        end_ebml_master(pb, track);
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        // ms precision is the de-facto standard timescale for mkv files
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        av_set_pts_info(st, 64, 1, 1000);
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    }
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    end_ebml_master(pb, tracks);
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    mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER);
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    put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, 0);
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    mkv->cluster_pts = 0;
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    return 0;
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}
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static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
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{
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    MatroskaMuxContext *mkv = s->priv_data;
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    ByteIOContext *pb = &s->pb;
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    offset_t block;
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    // start a new cluster every 5 MB or 5 sec
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    if (url_ftell(pb) > mkv->cluster + 5*1024*1024 || pkt->pts > mkv->cluster_pts + 5000) {
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        end_ebml_master(pb, mkv->cluster);
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        mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER);
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        put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
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        mkv->cluster_pts = pkt->pts;
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    }
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    block = start_ebml_master(pb, MATROSKA_ID_SIMPLEBLOCK);
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    put_byte(pb, 0x80 | (pkt->stream_index + 1));     // this assumes stream_index is less than 126
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    put_be16(pb, pkt->pts - mkv->cluster_pts);
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    put_byte(pb, !!(pkt->flags & PKT_FLAG_KEY));
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    put_buffer(pb, pkt->data, pkt->size);
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    end_ebml_master(pb, block);
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    mkv->duration = pkt->pts + pkt->duration;
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    return 0;
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}
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static int mkv_write_trailer(AVFormatContext *s)
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{
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    MatroskaMuxContext *mkv = s->priv_data;
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    ByteIOContext *pb = &s->pb;
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    offset_t currentpos;
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    end_ebml_master(pb, mkv->cluster);
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    // update the duration
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    currentpos = url_ftell(pb);
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    url_fseek(pb, mkv->duration_offset, SEEK_SET);
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    put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
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    url_fseek(pb, currentpos, SEEK_SET);
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    end_ebml_master(pb, mkv->segment);
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    return 0;
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}
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AVOutputFormat matroska_muxer = {
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    "matroska",
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    "Matroska File Format",
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    "video/x-matroska",
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    "mkv",
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    sizeof(MatroskaMuxContext),
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    CODEC_ID_MP2,
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    CODEC_ID_MPEG4,
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    mkv_write_header,
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    mkv_write_packet,
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    mkv_write_trailer,
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    .codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},
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};