music-metadata
Version:
Music metadata parser for Node.js, supporting virtual any audio and tag format.
570 lines (569 loc) • 24.1 kB
JavaScript
import * as Token from 'token-types';
import { EndOfStreamError } from 'strtok3';
import initDebug from 'debug';
import * as common from '../common/Util.js';
import { AbstractID3Parser } from '../id3v2/AbstractID3Parser.js';
import { InfoTagHeaderTag, LameEncoderVersion, readXingHeader } from './XingTag.js';
import { makeUnexpectedFileContentError } from '../ParseError.js';
const debug = initDebug('music-metadata:parser:mpeg');
export class MpegContentError extends makeUnexpectedFileContentError('MPEG') {
}
/**
* Cache buffer size used for searching synchronization preabmle
*/
const maxPeekLen = 1024;
/**
* MPEG-4 Audio definitions
* Ref: https://wiki.multimedia.cx/index.php/MPEG-4_Audio
*/
const MPEG4 = {
/**
* Audio Object Types
*/
AudioObjectTypes: [
'AAC Main',
'AAC LC', // Low Complexity
'AAC SSR', // Scalable Sample Rate
'AAC LTP' // Long Term Prediction
],
/**
* Sampling Frequencies
* https://wiki.multimedia.cx/index.php/MPEG-4_Audio#Sampling_Frequencies
*/
SamplingFrequencies: [
96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, 16000, 12000, 11025, 8000, 7350, null, null, -1
]
/**
* Channel Configurations
*/
};
const MPEG4_ChannelConfigurations = [
undefined,
['front-center'],
['front-left', 'front-right'],
['front-center', 'front-left', 'front-right'],
['front-center', 'front-left', 'front-right', 'back-center'],
['front-center', 'front-left', 'front-right', 'back-left', 'back-right'],
['front-center', 'front-left', 'front-right', 'back-left', 'back-right', 'LFE-channel'],
['front-center', 'front-left', 'front-right', 'side-left', 'side-right', 'back-left', 'back-right', 'LFE-channel']
];
/**
* MPEG Audio Layer I/II/III frame header
* Ref: https://www.mp3-tech.org/programmer/frame_header.html
* Bit layout: AAAAAAAA AAABBCCD EEEEFFGH IIJJKLMM
* Ref: https://wiki.multimedia.cx/index.php/ADTS
*/
class MpegFrameHeader {
constructor(buf, off) {
// E(15,12): Bitrate index
this.bitrateIndex = null;
// F(11,10): Sampling rate frequency index
this.sampRateFreqIndex = null;
// G(9): Padding bit
this.padding = null;
// H(8): Private bit
this.privateBit = null;
// I(7,6): Channel Mode
this.channelModeIndex = null;
// J(5,4): Mode extension (Only used in Joint stereo)
this.modeExtension = null;
// L(2): Original
this.isOriginalMedia = null;
this.version = null;
this.bitrate = null;
this.samplingRate = null;
this.frameLength = 0;
// B(20,19): MPEG Audio versionIndex ID
this.versionIndex = common.getBitAllignedNumber(buf, off + 1, 3, 2);
// C(18,17): Layer description
this.layer = MpegFrameHeader.LayerDescription[common.getBitAllignedNumber(buf, off + 1, 5, 2)];
if (this.versionIndex > 1 && this.layer === 0) {
this.parseAdtsHeader(buf, off); // Audio Data Transport Stream (ADTS)
}
else {
this.parseMpegHeader(buf, off); // Conventional MPEG header
}
// D(16): Protection bit (if true 16-bit CRC follows header)
this.isProtectedByCRC = !common.isBitSet(buf, off + 1, 7);
}
calcDuration(numFrames) {
return this.samplingRate == null ? null : (numFrames * this.calcSamplesPerFrame() / this.samplingRate);
}
calcSamplesPerFrame() {
return MpegFrameHeader.samplesInFrameTable[this.version === 1 ? 0 : 1][this.layer];
}
calculateSideInfoLength() {
if (this.layer !== 3)
return 2;
if (this.channelModeIndex === 3) {
// mono
if (this.version === 1) {
return 17;
}
if (this.version === 2 || this.version === 2.5) {
return 9;
}
}
else {
if (this.version === 1) {
return 32;
}
if (this.version === 2 || this.version === 2.5) {
return 17;
}
}
return null;
}
calcSlotSize() {
return [null, 4, 1, 1][this.layer];
}
parseMpegHeader(buf, off) {
this.container = 'MPEG';
// E(15,12): Bitrate index
this.bitrateIndex = common.getBitAllignedNumber(buf, off + 2, 0, 4);
// F(11,10): Sampling rate frequency index
this.sampRateFreqIndex = common.getBitAllignedNumber(buf, off + 2, 4, 2);
// G(9): Padding bit
this.padding = common.isBitSet(buf, off + 2, 6);
// H(8): Private bit
this.privateBit = common.isBitSet(buf, off + 2, 7);
// I(7,6): Channel Mode
this.channelModeIndex = common.getBitAllignedNumber(buf, off + 3, 0, 2);
// J(5,4): Mode extension (Only used in Joint stereo)
this.modeExtension = common.getBitAllignedNumber(buf, off + 3, 2, 2);
// K(3): Copyright
this.isCopyrighted = common.isBitSet(buf, off + 3, 4);
// L(2): Original
this.isOriginalMedia = common.isBitSet(buf, off + 3, 5);
// M(3): The original bit indicates, if it is set, that the frame is located on its original media.
this.emphasis = common.getBitAllignedNumber(buf, off + 3, 7, 2);
this.version = MpegFrameHeader.VersionID[this.versionIndex];
this.channelMode = MpegFrameHeader.ChannelMode[this.channelModeIndex];
this.codec = `MPEG ${this.version} Layer ${this.layer}`;
// Calculate bitrate
const bitrateInKbps = this.calcBitrate();
if (!bitrateInKbps) {
throw new MpegContentError('Cannot determine bit-rate');
}
this.bitrate = bitrateInKbps * 1000;
// Calculate sampling rate
this.samplingRate = this.calcSamplingRate();
if (this.samplingRate == null) {
throw new MpegContentError('Cannot determine sampling-rate');
}
}
parseAdtsHeader(buf, off) {
debug("layer=0 => ADTS");
this.version = this.versionIndex === 2 ? 4 : 2;
this.container = `ADTS/MPEG-${this.version}`;
const profileIndex = common.getBitAllignedNumber(buf, off + 2, 0, 2);
this.codec = 'AAC';
this.codecProfile = MPEG4.AudioObjectTypes[profileIndex];
debug(`MPEG-4 audio-codec=${this.codec}`);
const samplingFrequencyIndex = common.getBitAllignedNumber(buf, off + 2, 2, 4);
this.samplingRate = MPEG4.SamplingFrequencies[samplingFrequencyIndex];
debug(`sampling-rate=${this.samplingRate}`);
const channelIndex = common.getBitAllignedNumber(buf, off + 2, 7, 3);
this.mp4ChannelConfig = MPEG4_ChannelConfigurations[channelIndex];
debug(`channel-config=${this.mp4ChannelConfig ? this.mp4ChannelConfig.join('+') : '?'}`);
this.frameLength = common.getBitAllignedNumber(buf, off + 3, 6, 2) << 11;
}
calcBitrate() {
if (this.bitrateIndex === 0x00 || // free
this.bitrateIndex === 0x0F) { // reserved
return null;
}
if (this.version && this.bitrateIndex) {
const codecIndex = 10 * Math.floor(this.version) + this.layer;
return MpegFrameHeader.bitrate_index[this.bitrateIndex][codecIndex];
}
return null;
}
calcSamplingRate() {
if (this.sampRateFreqIndex === 0x03 || this.version === null || this.sampRateFreqIndex == null)
return null; // 'reserved'
return MpegFrameHeader.sampling_rate_freq_index[this.version][this.sampRateFreqIndex];
}
}
MpegFrameHeader.SyncByte1 = 0xFF;
MpegFrameHeader.SyncByte2 = 0xE0;
MpegFrameHeader.VersionID = [2.5, null, 2, 1];
MpegFrameHeader.LayerDescription = [0, 3, 2, 1];
MpegFrameHeader.ChannelMode = ['stereo', 'joint_stereo', 'dual_channel', 'mono'];
MpegFrameHeader.bitrate_index = {
1: { 11: 32, 12: 32, 13: 32, 21: 32, 22: 8, 23: 8 },
2: { 11: 64, 12: 48, 13: 40, 21: 48, 22: 16, 23: 16 },
3: { 11: 96, 12: 56, 13: 48, 21: 56, 22: 24, 23: 24 },
4: { 11: 128, 12: 64, 13: 56, 21: 64, 22: 32, 23: 32 },
5: { 11: 160, 12: 80, 13: 64, 21: 80, 22: 40, 23: 40 },
6: { 11: 192, 12: 96, 13: 80, 21: 96, 22: 48, 23: 48 },
7: { 11: 224, 12: 112, 13: 96, 21: 112, 22: 56, 23: 56 },
8: { 11: 256, 12: 128, 13: 112, 21: 128, 22: 64, 23: 64 },
9: { 11: 288, 12: 160, 13: 128, 21: 144, 22: 80, 23: 80 },
10: { 11: 320, 12: 192, 13: 160, 21: 160, 22: 96, 23: 96 },
11: { 11: 352, 12: 224, 13: 192, 21: 176, 22: 112, 23: 112 },
12: { 11: 384, 12: 256, 13: 224, 21: 192, 22: 128, 23: 128 },
13: { 11: 416, 12: 320, 13: 256, 21: 224, 22: 144, 23: 144 },
14: { 11: 448, 12: 384, 13: 320, 21: 256, 22: 160, 23: 160 }
};
MpegFrameHeader.sampling_rate_freq_index = {
1: { 0: 44100, 1: 48000, 2: 32000 },
2: { 0: 22050, 1: 24000, 2: 16000 },
2.5: { 0: 11025, 1: 12000, 2: 8000 }
};
MpegFrameHeader.samplesInFrameTable = [
/* Layer I II III */
[0, 384, 1152, 1152], // MPEG-1
[0, 384, 1152, 576] // MPEG-2(.5
];
/**
* MPEG Audio Layer I/II/III
*/
const FrameHeader = {
len: 4,
get: (buf, off) => {
return new MpegFrameHeader(buf, off);
}
};
function getVbrCodecProfile(vbrScale) {
return `V${Math.floor((100 - vbrScale) / 10)}`;
}
export class MpegParser extends AbstractID3Parser {
constructor() {
super(...arguments);
this.frameCount = 0;
this.syncFrameCount = -1;
this.totalDataLength = 0;
this.bitrates = [];
this.offset = 0;
this.frame_size = 0;
this.calculateEofDuration = false;
this.samplesPerFrame = null;
this.buf_frame_header = new Uint8Array(4);
/**
* Number of bytes already parsed since beginning of stream / file
*/
this.mpegOffset = null;
this.syncPeek = {
buf: new Uint8Array(maxPeekLen),
len: 0
};
}
/**
* Called after ID3 headers have been parsed
*/
async postId3v2Parse() {
this.metadata.setFormat('lossless', false);
this.metadata.setAudioOnly();
try {
let quit = false;
while (!quit) {
await this.sync();
quit = await this.parseCommonMpegHeader();
}
}
catch (err) {
if (err instanceof EndOfStreamError) {
debug("End-of-stream");
if (this.calculateEofDuration) {
if (this.samplesPerFrame !== null) {
const numberOfSamples = this.frameCount * this.samplesPerFrame;
this.metadata.setFormat('numberOfSamples', numberOfSamples);
if (this.metadata.format.sampleRate) {
const duration = numberOfSamples / this.metadata.format.sampleRate;
debug(`Calculate duration at EOF: ${duration} sec.`, duration);
this.metadata.setFormat('duration', duration);
}
}
}
}
else {
throw err;
}
}
}
/**
* Called after file has been fully parsed, this allows, if present, to exclude the ID3v1.1 header length
*/
finalize() {
const format = this.metadata.format;
const hasID3v1 = !!this.metadata.native.ID3v1;
if (this.mpegOffset !== null) {
if (format.duration && this.tokenizer.fileInfo.size) {
const mpegSize = this.tokenizer.fileInfo.size - this.mpegOffset - (hasID3v1 ? 128 : 0);
if (format.codecProfile && format.codecProfile[0] === 'V') {
this.metadata.setFormat('bitrate', mpegSize * 8 / format.duration);
}
}
if (this.tokenizer.fileInfo.size && format.codecProfile === 'CBR') {
const mpegSize = this.tokenizer.fileInfo.size - this.mpegOffset - (hasID3v1 ? 128 : 0);
if (this.frame_size !== null && this.samplesPerFrame !== null) {
const numberOfSamples = Math.round(mpegSize / this.frame_size) * this.samplesPerFrame;
this.metadata.setFormat('numberOfSamples', numberOfSamples);
if (format.sampleRate && !format.duration) {
const duration = numberOfSamples / format.sampleRate;
debug("Calculate CBR duration based on file size: %s", duration);
this.metadata.setFormat('duration', duration);
}
}
}
}
}
async sync() {
let gotFirstSync = false;
while (true) {
let bo = 0;
this.syncPeek.len = await this.tokenizer.peekBuffer(this.syncPeek.buf, { length: maxPeekLen, mayBeLess: true });
if (this.syncPeek.len <= 163) {
throw new EndOfStreamError();
}
while (true) {
if (gotFirstSync && (this.syncPeek.buf[bo] & 0xE0) === 0xE0) {
this.buf_frame_header[0] = MpegFrameHeader.SyncByte1;
this.buf_frame_header[1] = this.syncPeek.buf[bo];
await this.tokenizer.ignore(bo);
debug(`Sync at offset=${this.tokenizer.position - 1}, frameCount=${this.frameCount}`);
if (this.syncFrameCount === this.frameCount) {
debug(`Re-synced MPEG stream, frameCount=${this.frameCount}`);
this.frameCount = 0;
this.frame_size = 0;
}
this.syncFrameCount = this.frameCount;
return; // sync
}
gotFirstSync = false;
bo = this.syncPeek.buf.indexOf(MpegFrameHeader.SyncByte1, bo);
if (bo === -1) {
if (this.syncPeek.len < this.syncPeek.buf.length) {
throw new EndOfStreamError();
}
await this.tokenizer.ignore(this.syncPeek.len);
break; // continue with next buffer
}
++bo;
gotFirstSync = true;
}
}
}
/**
* Combined ADTS & MPEG (MP2 & MP3) header handling
* @return {Promise<boolean>} true if parser should quit
*/
async parseCommonMpegHeader() {
if (this.frameCount === 0) {
this.mpegOffset = this.tokenizer.position - 1;
}
await this.tokenizer.peekBuffer(this.buf_frame_header.subarray(1), { length: 3 });
let header;
try {
header = FrameHeader.get(this.buf_frame_header, 0);
}
catch (err) {
await this.tokenizer.ignore(1);
if (err instanceof Error) {
this.metadata.addWarning(`Parse error: ${err.message}`);
return false; // sync
}
throw err;
}
await this.tokenizer.ignore(3);
this.metadata.setFormat('container', header.container);
this.metadata.setFormat('codec', header.codec);
this.metadata.setFormat('lossless', false);
this.metadata.setFormat('sampleRate', header.samplingRate);
this.frameCount++;
return header.version !== null && header.version >= 2 && header.layer === 0 ? this.parseAdts(header) : this.parseAudioFrameHeader(header);
}
/**
* @return {Promise<boolean>} true if parser should quit
*/
async parseAudioFrameHeader(header) {
this.metadata.setFormat('numberOfChannels', header.channelMode === 'mono' ? 1 : 2);
this.metadata.setFormat('bitrate', header.bitrate);
if (this.frameCount < 20 * 10000) {
debug('offset=%s MP%s bitrate=%s sample-rate=%s', this.tokenizer.position - 4, header.layer, header.bitrate, header.samplingRate);
}
const slot_size = header.calcSlotSize();
if (slot_size === null) {
throw new MpegContentError('invalid slot_size');
}
const samples_per_frame = header.calcSamplesPerFrame();
debug(`samples_per_frame=${samples_per_frame}`);
const bps = samples_per_frame / 8.0;
if (header.bitrate !== null && header.samplingRate != null) {
const fsize = (bps * header.bitrate / header.samplingRate) + ((header.padding) ? slot_size : 0);
this.frame_size = Math.floor(fsize);
}
this.audioFrameHeader = header;
if (header.bitrate !== null) {
this.bitrates.push(header.bitrate);
}
// xtra header only exists in first frame
if (this.frameCount === 1) {
this.offset = FrameHeader.len;
await this.skipSideInformation();
return false;
}
if (this.frameCount === 4) {
// the stream is CBR if the first 3 frame bitrates are the same
if (this.areAllSame(this.bitrates)) {
// Actual calculation will be done in finalize
this.samplesPerFrame = samples_per_frame;
this.metadata.setFormat('codecProfile', 'CBR');
if (this.tokenizer.fileInfo.size)
return true; // Will calculate duration based on the file size
}
else if (this.metadata.format.duration) {
return true; // We already got the duration, stop processing MPEG stream any further
}
if (!this.options.duration) {
return true; // Enforce duration not enabled, stop processing entire stream
}
}
// once we know the file is VBR attach listener to end of
// stream so we can do the duration calculation when we
// have counted all the frames
if (this.options.duration && this.frameCount === 4) {
this.samplesPerFrame = samples_per_frame;
this.calculateEofDuration = true;
}
this.offset = 4;
if (header.isProtectedByCRC) {
await this.parseCrc();
return false;
}
await this.skipSideInformation();
return false;
}
async parseAdts(header) {
const buf = new Uint8Array(3);
await this.tokenizer.readBuffer(buf);
header.frameLength += common.getBitAllignedNumber(buf, 0, 0, 11);
this.totalDataLength += header.frameLength;
this.samplesPerFrame = 1024;
if (header.samplingRate !== null) {
const framesPerSec = header.samplingRate / this.samplesPerFrame;
const bytesPerFrame = this.frameCount === 0 ? 0 : this.totalDataLength / this.frameCount;
const bitrate = 8 * bytesPerFrame * framesPerSec + 0.5;
this.metadata.setFormat('bitrate', bitrate);
debug(`frame-count=${this.frameCount}, size=${header.frameLength} bytes, bit-rate=${bitrate}`);
}
await this.tokenizer.ignore(header.frameLength > 7 ? header.frameLength - 7 : 1);
// Consume remaining header and frame data
if (this.frameCount === 3) {
this.metadata.setFormat('codecProfile', header.codecProfile);
if (header.mp4ChannelConfig) {
this.metadata.setFormat('numberOfChannels', header.mp4ChannelConfig.length);
}
if (this.options.duration) {
this.calculateEofDuration = true;
}
else {
return true; // Stop parsing after the third frame
}
}
return false;
}
async parseCrc() {
await this.tokenizer.ignore(Token.INT16_BE.len); // Ignore CRC
this.offset += Token.INT16_BE.len;
return this.skipSideInformation();
}
async skipSideInformation() {
if (this.audioFrameHeader) {
const sideinfo_length = this.audioFrameHeader.calculateSideInfoLength();
if (sideinfo_length !== null) {
await this.tokenizer.readToken(new Token.Uint8ArrayType(sideinfo_length));
// side information
this.offset += sideinfo_length;
await this.readXtraInfoHeader();
return;
}
}
}
async readXtraInfoHeader() {
const headerTag = await this.tokenizer.readToken(InfoTagHeaderTag);
this.offset += InfoTagHeaderTag.len; // 12
switch (headerTag) {
case 'Info':
this.metadata.setFormat('codecProfile', 'CBR');
return this.readXingInfoHeader();
case 'Xing': {
const infoTag = await this.readXingInfoHeader();
if (infoTag.vbrScale !== null) {
const codecProfile = getVbrCodecProfile(infoTag.vbrScale);
this.metadata.setFormat('codecProfile', codecProfile);
}
return null;
}
case 'Xtra':
// ToDo: ???
break;
case 'LAME': {
const version = await this.tokenizer.readToken(LameEncoderVersion);
if (this.frame_size !== null && this.frame_size >= this.offset + LameEncoderVersion.len) {
this.offset += LameEncoderVersion.len;
this.metadata.setFormat('tool', `LAME ${version}`);
await this.skipFrameData(this.frame_size - this.offset);
return null;
}
this.metadata.addWarning('Corrupt LAME header');
break;
}
// ToDo: ???
}
// ToDo: promise duration???
const frameDataLeft = this.frame_size - this.offset;
if (frameDataLeft < 0) {
this.metadata.addWarning(`Frame ${this.frameCount}corrupt: negative frameDataLeft`);
}
else {
await this.skipFrameData(frameDataLeft);
}
return null;
}
/**
* Ref: http://gabriel.mp3-tech.org/mp3infotag.html
* @returns {Promise<string>}
*/
async readXingInfoHeader() {
const offset = this.tokenizer.position;
const infoTag = await readXingHeader(this.tokenizer);
this.offset += this.tokenizer.position - offset;
if (infoTag.lame) {
this.metadata.setFormat('tool', `LAME ${common.stripNulls(infoTag.lame.version)}`);
if (infoTag.lame.extended) {
// this.metadata.setFormat('trackGain', infoTag.lame.extended.track_gain);
this.metadata.setFormat('trackPeakLevel', infoTag.lame.extended.track_peak);
if (infoTag.lame.extended.track_gain) {
this.metadata.setFormat('trackGain', infoTag.lame.extended.track_gain.adjustment);
}
if (infoTag.lame.extended.album_gain) {
this.metadata.setFormat('albumGain', infoTag.lame.extended.album_gain.adjustment);
}
this.metadata.setFormat('duration', infoTag.lame.extended.music_length / 1000);
}
}
if (infoTag.streamSize && this.audioFrameHeader && infoTag.numFrames !== null) {
const duration = this.audioFrameHeader.calcDuration(infoTag.numFrames);
this.metadata.setFormat('duration', duration);
debug('Get duration from Xing header: %s', this.metadata.format.duration);
return infoTag;
}
// frames field is not present
const frameDataLeft = this.frame_size - this.offset;
await this.skipFrameData(frameDataLeft);
return infoTag;
}
async skipFrameData(frameDataLeft) {
if (frameDataLeft < 0)
throw new MpegContentError('frame-data-left cannot be negative');
await this.tokenizer.ignore(frameDataLeft);
}
areAllSame(array) {
const first = array[0];
return array.every(element => {
return element === first;
});
}
}