mp4-generator.js
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(function(window, videojs, undefined) {
'use strict';
var box, dinf, ftyp, mdat, mfhd, minf, moof, moov, mvex, mvhd, trak,
tkhd, mdia, mdhd, hdlr, sdtp, stbl, stsd, styp, traf, trex, trun,
types, MAJOR_BRAND, MINOR_VERSION, AVC1_BRAND, VIDEO_HDLR,
AUDIO_HDLR, HDLR_TYPES, ESDS, VMHD, SMHD, DREF, STCO, STSC, STSZ, STTS,
Uint8Array, DataView;
Uint8Array = window.Uint8Array;
DataView = window.DataView;
// pre-calculate constants
(function() {
var i;
types = {
avc1: [], // codingname
avcC: [],
btrt: [],
dinf: [],
dref: [],
esds: [],
ftyp: [],
hdlr: [],
mdat: [],
mdhd: [],
mdia: [],
mfhd: [],
minf: [],
moof: [],
moov: [],
mp4a: [], // codingname
mvex: [],
mvhd: [],
sdtp: [],
smhd: [],
stbl: [],
stco: [],
stsc: [],
stsd: [],
stsz: [],
stts: [],
styp: [],
tfdt: [],
tfhd: [],
traf: [],
trak: [],
trun: [],
trex: [],
tkhd: [],
vmhd: []
};
for (i in types) {
if (types.hasOwnProperty(i)) {
types[i] = [
i.charCodeAt(0),
i.charCodeAt(1),
i.charCodeAt(2),
i.charCodeAt(3)
];
}
}
MAJOR_BRAND = new Uint8Array([
'i'.charCodeAt(0),
's'.charCodeAt(0),
'o'.charCodeAt(0),
'm'.charCodeAt(0)
]);
AVC1_BRAND = new Uint8Array([
'a'.charCodeAt(0),
'v'.charCodeAt(0),
'c'.charCodeAt(0),
'1'.charCodeAt(0)
]);
MINOR_VERSION = new Uint8Array([0, 0, 0, 1]);
VIDEO_HDLR = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x00, // pre_defined
0x76, 0x69, 0x64, 0x65, // handler_type: 'vide'
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x56, 0x69, 0x64, 0x65,
0x6f, 0x48, 0x61, 0x6e,
0x64, 0x6c, 0x65, 0x72, 0x00 // name: 'VideoHandler'
]);
AUDIO_HDLR = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x00, // pre_defined
0x73, 0x6f, 0x75, 0x6e, // handler_type: 'soun'
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x53, 0x6f, 0x75, 0x6e,
0x64, 0x48, 0x61, 0x6e,
0x64, 0x6c, 0x65, 0x72, 0x00 // name: 'SoundHandler'
]);
HDLR_TYPES = {
"video":VIDEO_HDLR,
"audio": AUDIO_HDLR
};
DREF = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x01, // entry_count
0x00, 0x00, 0x00, 0x0c, // entry_size
0x75, 0x72, 0x6c, 0x20, // 'url' type
0x00, // version 0
0x00, 0x00, 0x01 // entry_flags
]);
ESDS = new Uint8Array([
0x00, // version
0x00, 0x00, 0x00, // flags
// ES_Descriptor
0x03, // tag, ES_DescrTag
0x19, // length
0x00, 0x00, // ES_ID
0x00, // streamDependenceFlag, URL_flag, reserved, streamPriority
// DecoderConfigDescriptor
0x04, // tag, DecoderConfigDescrTag
0x11, // length
0x40, // object type
0x15, // streamType
0x00, 0x06, 0x00, // bufferSizeDB
0x00, 0x00, 0xda, 0xc0, // maxBitrate
0x00, 0x00, 0xda, 0xc0, // avgBitrate
// DecoderSpecificInfo
0x05, // tag, DecoderSpecificInfoTag
0x02, // length
// ISO/IEC 14496-3, AudioSpecificConfig
0x11, // AudioObjectType, AAC LC.
0x90, // samplingFrequencyIndex, 8 -> 16000. channelConfig, 2 -> stereo.
0x06, 0x01, 0x02 // GASpecificConfig
]);
SMHD = new Uint8Array([
0x00, // version
0x00, 0x00, 0x00, // flags
0x00, 0x00, // balance, 0 means centered
0x00, 0x00 // reserved
]);
STCO = new Uint8Array([
0x00, // version
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x00 // entry_count
]);
STSC = STCO;
STSZ = new Uint8Array([
0x00, // version
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x00, // sample_size
0x00, 0x00, 0x00, 0x00, // sample_count
]);
STTS = STCO;
VMHD = new Uint8Array([
0x00, // version
0x00, 0x00, 0x01, // flags
0x00, 0x00, // graphicsmode
0x00, 0x00,
0x00, 0x00,
0x00, 0x00 // opcolor
]);
})();
box = function(type) {
var
payload = Array.prototype.slice.call(arguments, 1),
size = 0,
i = payload.length,
result,
view;
// calculate the total size we need to allocate
while (i--) {
size += payload[i].byteLength;
}
result = new Uint8Array(size + 8);
view = new DataView(result.buffer, result.byteOffset, result.byteLength);
view.setUint32(0, result.byteLength);
result.set(type, 4);
// copy the payload into the result
for (i = 0, size = 8; i < payload.length; i++) {
result.set(payload[i], size);
size += payload[i].byteLength;
}
return result;
};
dinf = function() {
return box(types.dinf, box(types.dref, DREF));
};
ftyp = function() {
return box(types.ftyp, MAJOR_BRAND, MINOR_VERSION, MAJOR_BRAND, AVC1_BRAND);
};
hdlr = function(type) {
return box(types.hdlr, HDLR_TYPES[type]);
};
mdat = function(data) {
return box(types.mdat, data);
};
mdhd = function(track) {
var result = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x02, // creation_time
0x00, 0x00, 0x00, 0x03, // modification_time
0x00, 0x01, 0x5f, 0x90, // timescale, 90,000 "ticks" per second
(track.duration >>> 24),
(track.duration >>> 16) & 0xFF,
(track.duration >>> 8) & 0xFF,
track.duration & 0xFF, // duration
0x55, 0xc4, // 'und' language (undetermined)
0x00, 0x00
]);
// Use the sample rate from the track metadata, when it is
// defined. The sample rate can be parsed out of an ADTS header, for
// instance.
if (track.samplerate) {
result[12] = (track.samplerate >>> 24);
result[13] = (track.samplerate >>> 16) & 0xFF;
result[14] = (track.samplerate >>> 8) & 0xFF;
result[15] = (track.samplerate) & 0xFF;
}
return box(types.mdhd, result);
};
mdia = function(track) {
return box(types.mdia, mdhd(track), hdlr(track.type), minf(track));
};
mfhd = function(sequenceNumber) {
return box(types.mfhd, new Uint8Array([
0x00,
0x00, 0x00, 0x00, // flags
(sequenceNumber & 0xFF000000) >> 24,
(sequenceNumber & 0xFF0000) >> 16,
(sequenceNumber & 0xFF00) >> 8,
sequenceNumber & 0xFF, // sequence_number
]));
};
minf = function(track) {
return box(types.minf,
track.type === 'video' ? box(types.vmhd, VMHD) : box(types.smhd, SMHD),
dinf(),
stbl(track));
};
moof = function(sequenceNumber, tracks) {
var
trackFragments = [],
i = tracks.length;
// build traf boxes for each track fragment
while (i--) {
trackFragments[i] = traf(tracks[i]);
}
return box.apply(null, [
types.moof,
mfhd(sequenceNumber)
].concat(trackFragments));
};
/**
* Returns a movie box.
* @param tracks {array} the tracks associated with this movie
* @see ISO/IEC 14496-12:2012(E), section 8.2.1
*/
moov = function(tracks) {
var
i = tracks.length,
boxes = [];
while (i--) {
boxes[i] = trak(tracks[i]);
}
return box.apply(null, [types.moov, mvhd(0xffffffff)].concat(boxes).concat(mvex(tracks)));
};
mvex = function(tracks) {
var
i = tracks.length,
boxes = [];
while (i--) {
boxes[i] = trex(tracks[i]);
}
return box.apply(null, [types.mvex].concat(boxes));
};
mvhd = function(duration) {
var
bytes = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x01, // creation_time
0x00, 0x00, 0x00, 0x02, // modification_time
0x00, 0x01, 0x5f, 0x90, // timescale, 90,000 "ticks" per second
(duration & 0xFF000000) >> 24,
(duration & 0xFF0000) >> 16,
(duration & 0xFF00) >> 8,
duration & 0xFF, // duration
0x00, 0x01, 0x00, 0x00, // 1.0 rate
0x01, 0x00, // 1.0 volume
0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x01, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x01, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x40, 0x00, 0x00, 0x00, // transformation: unity matrix
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, // pre_defined
0xff, 0xff, 0xff, 0xff // next_track_ID
]);
return box(types.mvhd, bytes);
};
sdtp = function(track) {
var
samples = track.samples || [],
bytes = new Uint8Array(4 + samples.length),
sample,
i;
// leave the full box header (4 bytes) all zero
// write the sample table
for (i = 0; i < samples.length; i++) {
sample = samples[i];
bytes[i + 4] = (sample.flags.dependsOn << 4) |
(sample.flags.isDependedOn << 2) |
(sample.flags.hasRedundancy);
}
return box(types.sdtp,
bytes);
};
stbl = function(track) {
return box(types.stbl,
stsd(track),
box(types.stts, STTS),
box(types.stsc, STSC),
box(types.stsz, STSZ),
box(types.stco, STCO));
};
(function() {
var videoSample, audioSample;
stsd = function(track) {
return box(types.stsd, new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x01
]), track.type === 'video' ? videoSample(track) : audioSample(track));
};
videoSample = function(track) {
var sequenceParameterSets = [], pictureParameterSets = [], i;
// assemble the SPSs
for (i = 0; i < track.sps.length; i++) {
sequenceParameterSets.push((track.sps[i].byteLength & 0xFF00) >>> 8);
sequenceParameterSets.push((track.sps[i].byteLength & 0xFF)); // sequenceParameterSetLength
sequenceParameterSets = sequenceParameterSets.concat(Array.prototype.slice.call(track.sps[i])); // SPS
}
// assemble the PPSs
for (i = 0; i < track.pps.length; i++) {
pictureParameterSets.push((track.pps[i].byteLength & 0xFF00) >>> 8);
pictureParameterSets.push((track.pps[i].byteLength & 0xFF));
pictureParameterSets = pictureParameterSets.concat(Array.prototype.slice.call(track.pps[i]));
}
return box(types.avc1, new Uint8Array([
0x00, 0x00, 0x00,
0x00, 0x00, 0x00, // reserved
0x00, 0x01, // data_reference_index
0x00, 0x00, // pre_defined
0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, // pre_defined
(track.width & 0xff00) >> 8,
track.width & 0xff, // width
(track.height & 0xff00) >> 8,
track.height & 0xff, // height
0x00, 0x48, 0x00, 0x00, // horizresolution
0x00, 0x48, 0x00, 0x00, // vertresolution
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x01, // frame_count
0x13,
0x76, 0x69, 0x64, 0x65,
0x6f, 0x6a, 0x73, 0x2d,
0x63, 0x6f, 0x6e, 0x74,
0x72, 0x69, 0x62, 0x2d,
0x68, 0x6c, 0x73, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, // compressorname
0x00, 0x18, // depth = 24
0x11, 0x11 // pre_defined = -1
]), box(types.avcC, new Uint8Array([
0x01, // configurationVersion
track.profileIdc, // AVCProfileIndication
track.profileCompatibility, // profile_compatibility
track.levelIdc, // AVCLevelIndication
0xff // lengthSizeMinusOne, hard-coded to 4 bytes
].concat([
track.sps.length // numOfSequenceParameterSets
]).concat(sequenceParameterSets).concat([
track.pps.length // numOfPictureParameterSets
]).concat(pictureParameterSets))), // "PPS"
box(types.btrt, new Uint8Array([
0x00, 0x1c, 0x9c, 0x80, // bufferSizeDB
0x00, 0x2d, 0xc6, 0xc0, // maxBitrate
0x00, 0x2d, 0xc6, 0xc0
])) // avgBitrate
);
};
audioSample = function(track) {
return box(types.mp4a, new Uint8Array([
// SampleEntry, ISO/IEC 14496-12
0x00, 0x00, 0x00,
0x00, 0x00, 0x00, // reserved
0x00, 0x01, // data_reference_index
// AudioSampleEntry, ISO/IEC 14496-12
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, 0x00, 0x00, // reserved
(track.channelcount & 0xff00) >> 8,
(track.channelcount & 0xff), // channelcount
(track.samplesize & 0xff00) >> 8,
(track.samplesize & 0xff), // samplesize
0x00, 0x00, // pre_defined
0x00, 0x00, // reserved
(track.samplerate & 0xff00) >> 8,
(track.samplerate & 0xff),
0x00, 0x00 // samplerate, 16.16
// MP4AudioSampleEntry, ISO/IEC 14496-14
]), box(types.esds, ESDS));
};
})();
styp = function() {
return box(types.styp, MAJOR_BRAND, MINOR_VERSION, MAJOR_BRAND);
};
tkhd = function(track) {
var result = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x07, // flags
0x00, 0x00, 0x00, 0x00, // creation_time
0x00, 0x00, 0x00, 0x00, // modification_time
(track.id & 0xFF000000) >> 24,
(track.id & 0xFF0000) >> 16,
(track.id & 0xFF00) >> 8,
track.id & 0xFF, // track_ID
0x00, 0x00, 0x00, 0x00, // reserved
(track.duration & 0xFF000000) >> 24,
(track.duration & 0xFF0000) >> 16,
(track.duration & 0xFF00) >> 8,
track.duration & 0xFF, // duration
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, // reserved
0x00, 0x00, // layer
0x00, 0x00, // alternate_group
0x01, 0x00, // non-audio track volume
0x00, 0x00, // reserved
0x00, 0x01, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x01, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x40, 0x00, 0x00, 0x00, // transformation: unity matrix
(track.width & 0xFF00) >> 8,
track.width & 0xFF,
0x00, 0x00, // width
(track.height & 0xFF00) >> 8,
track.height & 0xFF,
0x00, 0x00 // height
]);
return box(types.tkhd, result);
};
traf = function(track) {
var sampleDependencyTable = sdtp(track);
return box(types.traf,
box(types.tfhd, new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
(track.id & 0xFF000000) >> 24,
(track.id & 0xFF0000) >> 16,
(track.id & 0xFF00) >> 8,
(track.id & 0xFF) // track_ID
])),
box(types.tfdt, new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
0x00, 0x00, 0x00, 0x00 // baseMediaDecodeTime
])),
trun(track,
sampleDependencyTable.length +
16 + // tfhd
16 + // tfdt
8 + // traf header
16 + // mfhd
8 + // moof header
8), // mdat header
sampleDependencyTable);
};
/**
* Generate a track box.
* @param track {object} a track definition
* @return {Uint8Array} the track box
*/
trak = function(track) {
track.duration = track.duration || 0xffffffff;
return box(types.trak,
tkhd(track),
mdia(track));
};
trex = function(track) {
var result = new Uint8Array([
0x00, // version 0
0x00, 0x00, 0x00, // flags
(track.id & 0xFF000000) >> 24,
(track.id & 0xFF0000) >> 16,
(track.id & 0xFF00) >> 8,
(track.id & 0xFF), // track_ID
0x00, 0x00, 0x00, 0x01, // default_sample_description_index
0x00, 0x00, 0x00, 0x00, // default_sample_duration
0x00, 0x00, 0x00, 0x00, // default_sample_size
0x00, 0x01, 0x00, 0x01 // default_sample_flags
]);
// the last two bytes of default_sample_flags is the sample
// degradation priority, a hint about the importance of this sample
// relative to others. Lower the degradation priority for all sample
// types other than video.
if (track.type !== 'video') {
result[result.length - 1] = 0x00;
}
return box(types.trex, result);
};
trun = function(track, offset) {
var bytes, samples, sample, i;
samples = track.samples || [];
offset += 8 + 12 + (16 * samples.length);
bytes = [
0x00, // version 0
0x00, 0x0f, 0x01, // flags
(samples.length & 0xFF000000) >>> 24,
(samples.length & 0xFF0000) >>> 16,
(samples.length & 0xFF00) >>> 8,
samples.length & 0xFF, // sample_count
(offset & 0xFF000000) >>> 24,
(offset & 0xFF0000) >>> 16,
(offset & 0xFF00) >>> 8,
offset & 0xFF // data_offset
];
for (i = 0; i < samples.length; i++) {
sample = samples[i];
bytes = bytes.concat([
(sample.duration & 0xFF000000) >>> 24,
(sample.duration & 0xFF0000) >>> 16,
(sample.duration & 0xFF00) >>> 8,
sample.duration & 0xFF, // sample_duration
(sample.size & 0xFF000000) >>> 24,
(sample.size & 0xFF0000) >>> 16,
(sample.size & 0xFF00) >>> 8,
sample.size & 0xFF, // sample_size
(sample.flags.isLeading << 2) | sample.flags.dependsOn,
(sample.flags.isDependedOn << 6) |
(sample.flags.hasRedundancy << 4) |
(sample.flags.paddingValue << 1) |
sample.flags.isNonSyncSample,
sample.flags.degradationPriority & 0xF0 << 8,
sample.flags.degradationPriority & 0x0F, // sample_flags
(sample.compositionTimeOffset & 0xFF000000) >>> 24,
(sample.compositionTimeOffset & 0xFF0000) >>> 16,
(sample.compositionTimeOffset & 0xFF00) >>> 8,
sample.compositionTimeOffset & 0xFF // sample_composition_time_offset
]);
}
return box(types.trun, new Uint8Array(bytes));
};
window.videojs.mp4 = {
ftyp: ftyp,
mdat: mdat,
moof: moof,
moov: moov,
initSegment: function(tracks) {
var
fileType = ftyp(),
movie = moov(tracks),
result;
result = new Uint8Array(fileType.byteLength + movie.byteLength);
result.set(fileType);
result.set(movie, fileType.byteLength);
return result;
}
};
})(window, window.videojs);