jessibuca
Version:
a h5 live stream player
882 lines (809 loc) • 31.2 kB
text/typescript
class MP4 {
static types: Record<string, number[]> = {
avc1: [],
avcC: [],
btrt: [],
dinf: [],
dref: [],
esds: [],
ftyp: [], // 视频类型
hdlr: [],
mdat: [], // 视频数据
mdhd: [],
mdia: [],
mfhd: [],
minf: [],
moof: [], //
moov: [], // 视频信息(视频参数)
mp4a: [],
mvex: [],
mvhd: [],
sdtp: [],
stbl: [],
stco: [],
stsc: [],
stsd: [],
stsz: [],
stts: [],
tfdt: [],
tfhd: [],
traf: [],
// 视频参数（moov）中主要的子box 为track,每个track都是一个随时间变化的媒体序列，
// 时间单位为一个sample，可以是一帧数据，或者音频（注意，一帧音频可以分解成多个音频sample，所以音频一般用sample作为单位，而不用帧）
trak: [],
trun: [],
trex: [],
tkhd: [],
vmhd: [],
smhd: [],
free: [],
edts: [],
elst: [],
stss: []
} as const;
static constants: Record<string, Uint8Array> = {
FTYP: new Uint8Array([
0x69, 0x73, 0x6F, 0x6D, // major_brand: isom
0x0, 0x0, 0x02, 0x0, // minor_version: 0x20
0x69, 0x73, 0x6F, 0x6D, // isom
0x69, 0x73, 0x6F, 0x32, // iso
0x61, 0x76, 0x63, 0x31, // avc1
0x6D, 0x70, 0x34, 0x31, // MP4
0x00, 0x00, 0x00, 0x00
]),
STSD_PREFIX: new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
0x00, 0x00, 0x00, 0x01 // entry_count
]),
STTS: new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
0x00, 0x00, 0x00, 0x00 // entry_count
]),
STSZ: new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
0x00, 0x00, 0x00, 0x00, // sample_size
0x00, 0x00, 0x00, 0x00 // sample_count
]),
HDLR_VIDEO: new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
0x00, 0x00, 0x00, 0x00, // pre_defined
0x76, 0x69, 0x64, 0x65, // handler_type: 'vide'
0x00, 0x00, 0x00, 0x00, // reserved: 3 * 4 bytes
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x56, 0x69, 0x64, 0x65,
0x6F, 0x48, 0x61, 0x6E,
0x64, 0x6C, 0x65, 0x72, 0x00 // name: VideoHandler
]),
HDLR_AUDIO: new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
0x00, 0x00, 0x00, 0x00, // pre_defined
0x73, 0x6F, 0x75, 0x6E, // handler_type: 'soun'
0x00, 0x00, 0x00, 0x00, // reserved: 3 * 4 bytes
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x53, 0x6F, 0x75, 0x6E,
0x64, 0x48, 0x61, 0x6E,
0x64, 0x6C, 0x65, 0x72, 0x00 // name: SoundHandler
]),
DREF: new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
0x00, 0x00, 0x00, 0x01, // entry_count
0x00, 0x00, 0x00, 0x0C, // entry_size
0x75, 0x72, 0x6C, 0x20, // type 'url '
0x00, 0x00, 0x00, 0x01 // version(0) + flags
]),
// Sound media header
SMHD: new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
0x00, 0x00, 0x00, 0x00 // balance(2) + reserved(2)
]),
// video media header
VMHD: new Uint8Array([
0x00, 0x00, 0x00, 0x01, // version(0) + flags
0x00, 0x00, // graphicsmode: 2 bytes
0x00, 0x00, 0x00, 0x00, // opcolor: 3 * 2 bytes
0x00, 0x00
]),
};
// Generate a box
// Type是box的类型
// box的参数除了第一个为类型，其他参数都需要是二进制的arraybuffer类型。
static box(type: number[], ...datas: Uint8Array[]) {
// box前8位为预留位，这8位中前4位为数据size，
// 当size值为0时，表示该box为文件的最后一个box（仅存在于mdat box中），
// 当size值为1时，表示该box的size为large size（8位）
let size = 8;
let result = null;
let arrayCount = datas.length;
for (let i = 0; i < arrayCount; i++) {
size += datas[i].byteLength;
}
result = new Uint8Array(size);
result[0] = (size >>> 24) & 0xFF; // size
result[1] = (size >>> 16) & 0xFF;
result[2] = (size >>> 8) & 0xFF;
result[3] = (size) & 0xFF;
result.set(type, 4); // type
let offset = 8;
for (let i = 0; i < arrayCount; i++) { // data body
result.set(datas[i], offset);
offset += datas[i].byteLength;
}
return result;
}
// emit ftyp & moov
static generateInitSegment(meta: any, trakList: any, mdatBytes: number) {
// Ftypbox 是一个由四个字符组成的码字，用来表示编码类型、兼容协议或者媒体文件的用途。
// 在普通MP4文件中，ftyp box有且仅有一个，在文件的开始位置。
let ftyp = MP4.box(MP4.types.ftyp, MP4.constants.FTYP);
//
let free = MP4.box(MP4.types.free);
// allocate mdatbox init fps = 25
let offset = 8;
let mdatbox = new Uint8Array();
if (mdatBytes + offset >= Math.pow(2, 32) - 1) { //large size
offset = 16;
mdatbox = new Uint8Array(mdatBytes + offset);
mdatbox.set(new Uint8Array([0x00, 0x00, 0x00, 0x01]), 0);
mdatbox.set(MP4.types.mdat, 4);
mdatbox.set(new Uint8Array([
(mdatBytes + 8 >>> 56) & 0xFF,
(mdatBytes + 8 >>> 48) & 0xFF,
(mdatBytes + 8 >>> 40) & 0xFF,
(mdatBytes + 8 >>> 32) & 0xFF,
(mdatBytes + 8 >>> 24) & 0xFF,
(mdatBytes + 8 >>> 16) & 0xFF,
(mdatBytes + 8 >>> 8) & 0xFF,
(mdatBytes + 8) & 0xFF
]), 8);
} else {
mdatbox = new Uint8Array(mdatBytes + offset);
mdatbox[0] = (mdatBytes + 8 >>> 24) & 0xFF;
mdatbox[1] = (mdatBytes + 8 >>> 16) & 0xFF;
mdatbox[2] = (mdatBytes + 8 >>> 8) & 0xFF;
mdatbox[3] = (mdatBytes + 8) & 0xFF;
mdatbox.set(MP4.types.mdat, 4);
}
// Write samples into mdatbox
for (let i = 0; i < trakList.length; i++) {
let trak = trakList[i];
trak.duration = trak.refSampleDuration * trak.sequenceNumber;
for (let j = 0; j < trak.sequenceNumber; j++) {
let sample = trak.samples[j];
sample.chunkOffset = ftyp.byteLength + free.byteLength + offset;
let units = [], unitLen = sample.units.length;
for (let n = 0; n < unitLen; n++) {
units[n] = Object.assign({}, sample.units[n]);
}
while (units.length) {
let unit = units.shift();
let data = unit.data;
mdatbox.set(data, offset);
offset += data.byteLength;
}
}
}
// Moov box中存放着媒体信息，上面提到的stbl里存放帧信息，属于媒体信息，也在moov box里。Moov box 用来描述媒体数据。
// Moov box 主要包含 mvhd、trak、mvex三种子box。
let moov = MP4.moov(meta, trakList);
//
let result = new Uint8Array(ftyp.byteLength + moov.byteLength + mdatbox.byteLength + free.byteLength);
result.set(ftyp, 0);
result.set(free, ftyp.byteLength);
result.set(mdatbox, ftyp.byteLength + free.byteLength);
result.set(moov, ftyp.byteLength + mdatbox.byteLength + free.byteLength);
return result;
}
// Movie metadata box
// Moov box 主要包含 mvhd、trak、mvex三种子box。
static moov(meta: any, trakList: any) {
let timescale = meta.timescale;
let duration = meta.duration;
let trakLen = trakList.length;
// Mvhd box定义了整个文件的特性
let mvhd = MP4.mvhd(timescale, duration);
let trakArrayBuffer = new Uint8Array();
for (let i = 0; i < trakLen; i++) {
let trak = MP4.trak(trakList[i]);
let arrayBuffer = new Uint8Array(trak.byteLength + trakArrayBuffer.byteLength);
arrayBuffer.set(trakArrayBuffer, 0);
arrayBuffer.set(trak, trakArrayBuffer.byteLength);
trakArrayBuffer = new Uint8Array(arrayBuffer.byteLength);
trakArrayBuffer.set(arrayBuffer, 0);
}
return MP4.box(MP4.types.moov, mvhd, trakArrayBuffer);
}
// Movie header box
// 这里写mp4时需要传入的参数为Time scale 和 Duration，其他的使用默认值即可。
static mvhd(timescale: number, duration: number) {
//
return MP4.box(MP4.types.mvhd, new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
0xCE, 0xBA, 0xFD, 0xA8, // creation_time
0xCE, 0xBA, 0xFD, 0xA8, // modification_time
(timescale >>> 24) & 0xFF, // timescale: 4 bytes
(timescale >>> 16) & 0xFF,
(timescale >>> 8) & 0xFF,
(timescale) & 0xFF,
(duration >>> 24) & 0xFF, // duration: 4 bytes
(duration >>> 16) & 0xFF,
(duration >>> 8) & 0xFF,
(duration) & 0xFF,
0x00, 0x01, 0x00, 0x00, // Preferred rate: 1.0
0x01, 0x00, 0x00, 0x00, // PreferredVolume(1.0, 2bytes) + reserved(2bytes)
0x00, 0x00, 0x00, 0x00, // reserved: 4 + 4 bytes
0x00, 0x00, 0x00, 0x00,
0x00, 0x01, 0x00, 0x00, // ----begin composition matrix----
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, // ----end composition matrix----
0x00, 0x00, 0x00, 0x00, // ----begin pre_defined 6 * 4 bytes----
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, // ----end pre_defined 6 * 4 bytes----
0x00, 0x00, 0x00, 0x03 // next_track_ID: 4 bytes 3
]));
}
// Track box
// 一个Track box定义了movie中的一个track。一部movie可以包含一个或多个tracks，它们之间相互独立，各自有各自的时间和空间信息。每个track box 都有与之关联的mdat box。
// 包含媒体数据引用和描述
// 包含modifier track
// 写mp4时仅用到第一个目的，所以这里只介绍媒体数据的引用和描述。
// 一个trak box一般主要包含了tkhd box、 edts box 、mdia box
static trak(trak: any) {
return MP4.box(MP4.types.trak, MP4.tkhd(trak)!, MP4.mdia(trak));
}
// Track header box
// 用来描述trak box的header 信息，定义了一个trak的时间、空间、音量信息。
static tkhd(trak: any) {
let trackId = trak.id, duration = trak.duration;
let width = trak.presentWidth, height = trak.presentHeight;
if (trak.type === 'video') {
return MP4.box(MP4.types.tkhd, new Uint8Array([
0x00, 0x00, 0x00, 0x0F, // version(0) + flags
0xCE, 0xBA, 0xFD, 0xA8, // creation_time
0xCE, 0xBA, 0xFD, 0xA8, // modification_time
(trackId >>> 24) & 0xFF, // track_ID: 4 bytes
(trackId >>> 16) & 0xFF,
(trackId >>> 8) & 0xFF,
(trackId) & 0xFF,
0x00, 0x00, 0x00, 0x00, // reserved: 4 bytes
(duration >>> 24) & 0xFF, // duration: 4 bytes
(duration >>> 16) & 0xFF,
(duration >>> 8) & 0xFF,
(duration) & 0xFF,
0x00, 0x00, 0x00, 0x00, // reserved: 2 * 4 bytes
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, // layer(2bytes) + alternate_group(2bytes)
0x00, 0x00, 0x00, 0x00, // volume(2bytes) + reserved(2bytes)
0x00, 0x01, 0x00, 0x00, // ----begin composition matrix----
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, // ----end composition matrix----
(width >>> 8) & 0xFF, // width and height
(width) & 0xFF,
0x00, 0x00,
(height >>> 8) & 0xFF,
(height) & 0xFF,
0x00, 0x00
]));
} else if (trak.type === 'audio') {
return MP4.box(MP4.types.tkhd, new Uint8Array([
0x00, 0x00, 0x00, 0x0F, // version(0) + flags
0xCE, 0xBA, 0xFD, 0xA8, // creation_time
0xCE, 0xBA, 0xFD, 0xA8, // modification_time
(trackId >>> 24) & 0xFF, // track_ID: 4 bytes
(trackId >>> 16) & 0xFF,
(trackId >>> 8) & 0xFF,
(trackId) & 0xFF,
0x00, 0x00, 0x00, 0x00, // reserved: 4 bytes
(duration >>> 24) & 0xFF, // duration: 4 bytes
(duration >>> 16) & 0xFF,
(duration >>> 8) & 0xFF,
(duration) & 0xFF,
0x00, 0x00, 0x00, 0x00, // reserved: 2 * 4 bytes
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, // layer(2bytes) + alternate_group(2bytes)
0x00, 0x00, 0x00, 0x00, // volume(2bytes) + reserved(2bytes)
0x00, 0x01, 0x00, 0x00, // ----begin composition matrix----
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, // ----end composition matrix----
0x00, 0x00, 0x00, 0x00, // audio （8 bytes 0）
0x00, 0x00, 0x00, 0x00
]));
}
}
static edts(meta: any, i: number) {
return MP4.box(MP4.types.edts, MP4.elst(meta, i));
}
// 该box为edst box的唯一子box，不是所有的MP4文件都有edst box，这个box是使其对应的trak box的时间戳产生偏移。
// 暂时未发现需要该偏移量的地方，编码时也未对该box进行编码。
static elst(meta: any, i: number) {
let videoList = [], videoDelayDuration = 0;
for (let j = 0; j < i; j++) {
if (meta[j].type === 'video') {
videoDelayDuration += meta[j].duration;
}
}
let duration = meta[i].duration;
if (videoDelayDuration === 0) {
videoDelayDuration = meta[i].refSampleDuration;
}
return MP4.box(MP4.types.elst, new Uint8Array([
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x02,
(videoDelayDuration >>> 24) & 0xFF, // SampleDuration: 4 bytes
(videoDelayDuration >>> 16) & 0xFF,
(videoDelayDuration >>> 8) & 0xFF,
(videoDelayDuration) & 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, //media_time
0x00, 0x01, 0x00, 0x00, // media_rate(2byte) + Media rate fraction(3byte)
(duration >>> 24) & 0xFF, // Duration: 4 bytes
(duration >>> 16) & 0xFF,
(duration >>> 8) & 0xFF,
(duration) & 0xFF,
0x00, 0x00, 0x00, 0x00,
0x00, 0x01, 0x00, 0x00
]));
}
// Media Box
// 该box定义了trak box的类型和sample的信息。
static mdia(trak: any) {
return MP4.box(MP4.types.mdia, MP4.mdhd(trak), MP4.hdlr(trak), MP4.minf(trak));
}
// Media header box
static mdhd(trak: any) {
let timescale = trak.timescale / trak.refSampleDuration;
let duration = timescale * trak.duration / trak.timescale;
return MP4.box(MP4.types.mdhd, new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
0xCE, 0xBA, 0xFD, 0xA8, // creation_time
0xCE, 0xBA, 0xFD, 0xA8, // modification_time
(timescale >>> 24) & 0xFF, // timescale: 4 bytes
(timescale >>> 16) & 0xFF,
(timescale >>> 8) & 0xFF,
(timescale) & 0xFF,
(duration >>> 24) & 0xFF, // duration: 4 bytes
(duration >>> 16) & 0xFF,
(duration >>> 8) & 0xFF,
(duration) & 0xFF,
0x55, 0xC4, // language: und (undetermined)
0x00, 0x00 // pre_defined = 0
]));
}
// Media handler reference box
static hdlr(meta: any) {
let data = null;
if (meta.type === 'audio') {
data = MP4.constants.HDLR_AUDIO;
} else {
data = MP4.constants.HDLR_VIDEO;
}
return MP4.box(MP4.types.hdlr, data);
}
// Media infomation box
static minf(trak: any) {
let xmhd = null;
if (trak.type === 'audio') {
xmhd = MP4.box(MP4.types.smhd, MP4.constants.SMHD);
} else {
xmhd = MP4.box(MP4.types.vmhd, MP4.constants.VMHD);
}
return MP4.box(MP4.types.minf, xmhd, MP4.dinf(), MP4.stbl(trak));
}
// Data infomation box
static dinf() {
return MP4.box(MP4.types.dinf,
MP4.box(MP4.types.dref, MP4.constants.DREF)
);
}
// Sample table box
// 在普通mp4中，在获取数据之前，需要解析每个帧数据所在位置，每个帧数据都存放在mdat中，而这些帧的信息全部存放在stbl box 中，
// 所以，若要mp4文件能够正常播放，需要在写mp4文件时，将所有的帧数据信息写入 stbl box中。
static stbl(trak: any) {
let sampleList = trak.samples;
let sampleToChunk = [
{
No: 1,
num: 0,
sampleDelte: 1,
chunkNo: 1,
duration: sampleList[0].duration
}
];
let durationList = [sampleList[0].duration];
let len = sampleList.length;
for (let i = 0; i < len; i++) {
for (let j = 0; j < sampleToChunk.length; j++) {
if (sampleList[i].duration === sampleToChunk[j].duration) {
sampleToChunk[j].num++;
} else {
if (durationList.indexOf(sampleList[i].duration) < 0) {
durationList.push(sampleList[i].duration);
sampleToChunk.push({
No: 2,
num: 0,
sampleDelte: 1,
chunkNo: i + 1,
duration: sampleList[i].duration
});
}
}
}
}
return MP4.box(MP4.types.stbl, // type: stbl
MP4.stsd(trak), // Sample Description Table
MP4.stts(sampleToChunk), // Time-To-Sample
MP4.stss(sampleList),
MP4.stsc(sampleToChunk), //Sample-To-Chunk
MP4.stsz(sampleList), // Sample size
MP4.stco(sampleToChunk, sampleList)// Chunk offset
);
}
static stts(sampleToChunk: any) {
let sampleToChunkLen = sampleToChunk.length;
let stts = new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
(sampleToChunkLen >>> 24) & 0xFF, // entry_count: 4 bytes
(sampleToChunkLen >>> 16) & 0xFF,
(sampleToChunkLen >>> 8) & 0xFF,
(sampleToChunkLen) & 0xFF
]);
let offset = stts.byteLength, sttsInfo = new Uint8Array(offset + sampleToChunkLen * 8);
sttsInfo.set(stts, 0);
for (let index = 0; index < sampleToChunkLen; index++) {
sttsInfo.set(new Uint8Array([
(sampleToChunk[index].num >>> 24) & 0xFF, // samplesPerChunk: 4 bytes
(sampleToChunk[index].num >>> 16) & 0xFF,
(sampleToChunk[index].num >>> 8) & 0xFF,
(sampleToChunk[index].num) & 0xFF,
(sampleToChunk[index].sampleDelte >>> 24) & 0xFF, // samplesDescription index: 4 bytes
(sampleToChunk[index].sampleDelte >>> 16) & 0xFF,
(sampleToChunk[index].sampleDelte >>> 8) & 0xFF,
(sampleToChunk[index].sampleDelte) & 0xFF
]), offset);
offset += 8;
}
return MP4.box(MP4.types.stts, sttsInfo);
}
static stss(mdatDataList: any) {
let keyFrameMap = [], len = mdatDataList.length;
for (let i = 0; i < len; i++) {
if (mdatDataList[i].isKeyframe === true) {
keyFrameMap.push(i + 1);
}
}
let keyFrameLen = keyFrameMap.length;
let stss = new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
(keyFrameLen >>> 24) & 0xFF, // entry_count: 4 bytes
(keyFrameLen >>> 16) & 0xFF,
(keyFrameLen >>> 8) & 0xFF,
(keyFrameLen) & 0xFF
]);
let offset = stss.byteLength, stssInfo = new Uint8Array(offset + keyFrameLen * 4);
stssInfo.set(stss, 0);
for (let index = 0; index < keyFrameLen; index++) {
stssInfo.set(new Uint8Array([
(keyFrameMap[index] >>> 24) & 0xFF, // entry_count: 4 bytes
(keyFrameMap[index] >>> 16) & 0xFF,
(keyFrameMap[index] >>> 8) & 0xFF,
(keyFrameMap[index]) & 0xFF
]), offset);
offset += 4;
}
return MP4.box(MP4.types.stss, stssInfo);
}
static stsc(sampleToChunk: any) {
let sampleToChunkLen = sampleToChunk.length;
let stsc = new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
(sampleToChunkLen >>> 24) & 0xFF, // entry_count: 4 bytes
(sampleToChunkLen >>> 16) & 0xFF,
(sampleToChunkLen >>> 8) & 0xFF,
(sampleToChunkLen) & 0xFF
]);
let offset = stsc.byteLength, stscInfo = new Uint8Array(offset + sampleToChunkLen * 12);
stscInfo.set(stsc, 0);
for (let index = 0; index < sampleToChunkLen; index++) {
let firstChunk = sampleToChunk[index].chunkNo, samplesPerChunk = sampleToChunk[index].num,
sampleDelte = sampleToChunk[index].sampleDelte;
stscInfo.set(new Uint8Array([
(firstChunk >>> 24) & 0xFF, // firstChunk: 4 bytes
(firstChunk >>> 16) & 0xFF,
(firstChunk >>> 8) & 0xFF,
(firstChunk) & 0xFF,
(samplesPerChunk >>> 24) & 0xFF, // samplesPerChunk: 4 bytes
(samplesPerChunk >>> 16) & 0xFF,
(samplesPerChunk >>> 8) & 0xFF,
(samplesPerChunk) & 0xFF,
(sampleDelte >>> 24) & 0xFF, // samplesDescription index: 4 bytes
(sampleDelte >>> 16) & 0xFF,
(sampleDelte >>> 8) & 0xFF,
(sampleDelte) & 0xFF
]), offset);
offset += 12;
}
return MP4.box(MP4.types.stsc, stscInfo);
}
static stsz(mdatDataList: any) {
let len = mdatDataList.length;
let stsz = new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
0x00, 0x00, 0x00, 0x00, // sample size 当所有sample的size都一样时，该值为sample的size ，否则为0
(len >>> 24) & 0xFF, // sample count: 4 bytes
(len >>> 16) & 0xFF,
(len >>> 8) & 0xFF,
(len) & 0xFF
]);
let offset = stsz.byteLength, stszInfo = new Uint8Array(offset + len * 4);
stszInfo.set(stsz, 0);
for (let i = 0; i < len; i++) {
let units = mdatDataList[i].units;
while (units.length) {
let unit = units.shift();
let data = unit.data;
let dataLen = data.byteLength;
if (offset < stszInfo.length) {
stszInfo.set(new Uint8Array([
(dataLen >>> 24) & 0xFF, //per sample size: 4 bytes
(dataLen >>> 16) & 0xFF,
(dataLen >>> 8) & 0xFF,
(dataLen) & 0xFF
]), offset);
offset += 4;
}
}
}
return MP4.box(MP4.types.stsz, stszInfo);
}
static stco(sampleToChunk: any, mdatDataList: any) {
let offset = mdatDataList[0].chunkOffset;
return MP4.box(MP4.types.stco, new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
0x00, 0x00, 0x00, 0x01, // entry_count: 4 bytes //默认只有视频时，只有一段chunk
(offset >>> 24) & 0xFF, // samplesPerChunk: 4 bytes
(offset >>> 16) & 0xFF,
(offset >>> 8) & 0xFF,
(offset) & 0xFF
]));
}
// Sample description box
static stsd(meta: any) {
if (meta.type === 'audio') {
// else: aac -> mp4a
return MP4.box(MP4.types.stsd, MP4.constants.STSD_PREFIX, MP4.mp4a(meta));
} else {
return MP4.box(MP4.types.stsd, MP4.constants.STSD_PREFIX, MP4.avc1(meta));
}
}
static mp4a(meta: any) {
let channelCount = meta.channelCount;
let sampleRate = meta.audioSampleRate;
let data = new Uint8Array([
0x00, 0x00, 0x00, 0x00, // reserved(4)
0x00, 0x00, 0x00, 0x01, // reserved(2) + data_reference_index(2)
0x00, 0x00, 0x00, 0x00, // reserved: 2 * 4 bytes
0x00, 0x00, 0x00, 0x00,
0x00, channelCount, // channelCount(2)
0x00, 0x10, // sampleSize(2)
0x00, 0x00, 0x00, 0x00, // reserved(4)
(sampleRate >>> 8) & 0xFF, // Audio sample rate
(sampleRate) & 0xFF,
0x00, 0x00
]);
return MP4.box(MP4.types.mp4a, data, MP4.esds(meta));
}
static esds(meta: any) {
let config = meta.config || [];
let configSize = config.length;
let data = new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version 0 + flags
0x03, // descriptor_type
0x17 + configSize, // length3
0x00, 0x01, // es_id
0x00, // stream_priority
0x04, // descriptor_type
0x0F + configSize, // length
0x40, // codec: mpeg4_audio
0x15, // stream_type: Audio
0x00, 0x00, 0x00, // buffer_size
0x00, 0x00, 0x00, 0x00, // maxBitrate
0x00, 0x00, 0x00, 0x00, // avgBitrate
0x05 // descriptor_type
].concat([
configSize
]).concat(
config
).concat([
0x06, 0x01, 0x02 // GASpecificConfig
]));
return MP4.box(MP4.types.esds, data);
}
static avc1(meta: any) {
let avcc = meta.avcc;
let width = meta.codecWidth, height = meta.codecHeight;
let data = new Uint8Array([
0x00, 0x00, 0x00, 0x00, // reserved(4)
0x00, 0x00, 0x00, 0x01, // reserved(2) + data_reference_index(2)
0x00, 0x00, 0x00, 0x00, // pre_defined(2) + reserved(2)
0x00, 0x00, 0x00, 0x00, // pre_defined: 3 * 4 bytes
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
(width >>> 8) & 0xFF, // width: 2 bytes
(width) & 0xFF,
(height >>> 8) & 0xFF, // height: 2 bytes
(height) & 0xFF,
0x00, 0x48, 0x00, 0x00, // horizresolution: 4 bytes
0x00, 0x48, 0x00, 0x00, // vertresolution: 4 bytes
0x00, 0x00, 0x00, 0x00, // reserved: 4 bytes
0x00, 0x01, // frame_count
0x0A, // strlen 10bytes
0x78, 0x71, 0x71, 0x2F, // compressorname: 32 bytes xqq/flv.js
0x66, 0x6C, 0x76, 0x2E,
0x6A, 0x73, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00,
0x00, 0x18, // depth
0xFF, 0xFF // pre_defined = -1
]);
return MP4.box(MP4.types.avc1, data, MP4.box(MP4.types.avcC, avcc));
}
// Movie Extends box
static mvex(meta: any) {
return MP4.box(MP4.types.mvex, MP4.trex(meta));
}
// Track Extends box
static trex(meta: any) {
let trackId = meta.id;
let data = new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) + flags
(trackId >>> 24) & 0xFF, // track_ID
(trackId >>> 16) & 0xFF,
(trackId >>> 8) & 0xFF,
(trackId) & 0xFF,
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
]);
return MP4.box(MP4.types.trex, data);
}
// Movie fragment box
static moof(track: any, baseMediaDecodeTime: number) {
return MP4.box(MP4.types.moof, MP4.mfhd(track.sequenceNumber), MP4.traf(track, baseMediaDecodeTime));
}
static mfhd(sequenceNumber: number) {
let data = new Uint8Array([
0x00, 0x00, 0x00, 0x00,
(sequenceNumber >>> 24) & 0xFF, // sequence_number: int32
(sequenceNumber >>> 16) & 0xFF,
(sequenceNumber >>> 8) & 0xFF,
(sequenceNumber) & 0xFF
]);
return MP4.box(MP4.types.mfhd, data);
}
// Track fragment box
static traf(track: any, baseMediaDecodeTime: number) {
let trackId = track.id;
// Track fragment header box
let tfhd = MP4.box(MP4.types.tfhd, new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) & flags
(trackId >>> 24) & 0xFF, // track_ID
(trackId >>> 16) & 0xFF,
(trackId >>> 8) & 0xFF,
(trackId) & 0xFF
]));
// Track Fragment Decode Time
let tfdt = MP4.box(MP4.types.tfdt, new Uint8Array([
0x00, 0x00, 0x00, 0x00, // version(0) & flags
(baseMediaDecodeTime >>> 24) & 0xFF, // baseMediaDecodeTime: int32
(baseMediaDecodeTime >>> 16) & 0xFF,
(baseMediaDecodeTime >>> 8) & 0xFF,
(baseMediaDecodeTime) & 0xFF
]));
let sdtp = MP4.sdtp(track);
let trun = MP4.trun(track, sdtp.byteLength + 16 + 16 + 8 + 16 + 8 + 8);
return MP4.box(MP4.types.traf, tfhd, tfdt, trun, sdtp);
}
// Sample Dependency Type box
static sdtp(track: any) {
let samples = track.samples || [];
let sampleCount = samples.length;
let data = new Uint8Array(4 + sampleCount);
// 0~4 bytes: version(0) & flags
for (let i = 0; i < sampleCount; i++) {
let flags = samples[i].flags;
data[i + 4] = (flags.isLeading << 6) // is_leading: 2 (bit)
| (flags.dependsOn << 4) // sample_depends_on
| (flags.isDependedOn << 2) // sample_is_depended_on
| (flags.hasRedundancy); // sample_has_redundancy
}
return MP4.box(MP4.types.sdtp, data);
}
// Track fragment run box
static trun(track: any, offset: number) {
let samples = track.samples || [];
let sampleCount = samples.length;
let dataSize = 12 + 16 * sampleCount;
let data = new Uint8Array(dataSize);
offset += 8 + dataSize;
data.set([
0x00, 0x00, 0x0F, 0x01, // version(0) & flags
(sampleCount >>> 24) & 0xFF, // sample_count
(sampleCount >>> 16) & 0xFF,
(sampleCount >>> 8) & 0xFF,
(sampleCount) & 0xFF,
(offset >>> 24) & 0xFF, // data_offset
(offset >>> 16) & 0xFF,
(offset >>> 8) & 0xFF,
(offset) & 0xFF
], 0);
for (let i = 0; i < sampleCount; i++) {
let duration = samples[i].duration;
let size = samples[i].size;
let flags = samples[i].flags;
let cts = samples[i].cts;
data.set([
(duration >>> 24) & 0xFF, // sample_duration
(duration >>> 16) & 0xFF,
(duration >>> 8) & 0xFF,
(duration) & 0xFF,
(size >>> 24) & 0xFF, // sample_size
(size >>> 16) & 0xFF,
(size >>> 8) & 0xFF,
(size) & 0xFF,
(flags.isLeading << 2) | flags.dependsOn, // sample_flags
(flags.isDependedOn << 6) | (flags.hasRedundancy << 4) | flags.isNonSync,
0x00, 0x00, // sample_degradation_priority
(cts >>> 24) & 0xFF, // sample_composition_time_offset
(cts >>> 16) & 0xFF,
(cts >>> 8) & 0xFF,
(cts) & 0xFF
], 12 + 16 * i);
}
return MP4.box(MP4.types.trun, data);
}
// Mdat box 中包含了MP4文件的媒体数据，在文件中的位置可以在moov的前面，也可以在moov的后面，
// 因我们这里用到MP4文件格式用来写mp4文件，需要计算每一帧媒体数据在文件中的偏移量，为了方便计算，mdat放置moov前面。
// Mdat box数据格式单一，无子box。主要分为box header 和box body，box header中存放box size 和box type（mdat），box body中存放所有媒体数据，媒体数据以sample为数据单元。
// 这里使用时，视频数据中，每一个sample是一个视频帧，存放sample时，需要根据帧数据类型进行拼帧处理后存放。
static mdat(data: Uint8Array) {
return MP4.box(MP4.types.mdat, data);
}
}
for (let name in MP4.types) {
if (MP4.types.hasOwnProperty(name)) {
MP4.types[name] = [
name.charCodeAt(0),
name.charCodeAt(1),
name.charCodeAt(2),
name.charCodeAt(3)
];
}
}
MP4.constants.STSC = MP4.constants.STTS;
MP4.constants.STCO = MP4.constants.STTS;
export default MP4;