@echogarden/wave-codec
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A fully-featured WAVE format encoder and decoder. Written in pure TypeScript.
123 lines • 5.79 kB
JavaScript
import { readUint16LE, readUint32LE, writeAscii, writeUint16LE, writeUint32LE } from './utilities/BinaryUtilities.js';
import { encodeHex, decodeHex } from './encodings/Hex.js';
export class WaveFormatHeader {
sampleFormat; // 2 bytes LE
channelCount; // 2 bytes LE
sampleRate; // 4 bytes LE
get byteRate() { return this.sampleRate * this.bytesPerSample * this.channelCount; } // 4 bytes LE
get blockAlign() { return this.bytesPerSample * this.channelCount; } // 2 bytes LE
bitDepth; // 2 bytes LE
speakerPositionMask; // 4 bytes LE
get guid() { return sampleFormatToGuid[this.sampleFormat]; } // 16 bytes BE
// Helpers:
get bytesPerSample() { return this.bitDepth / 8; }
constructor(channelCount, sampleRate, bitDepth, sampleFormat, speakerPositionMask = 0) {
this.sampleFormat = sampleFormat;
this.channelCount = channelCount;
this.sampleRate = sampleRate;
this.bitDepth = bitDepth;
this.speakerPositionMask = speakerPositionMask;
}
serialize(useExtensibleFormat) {
let sampleFormatId = this.sampleFormat;
if (useExtensibleFormat) {
sampleFormatId = 65534;
}
const serializedSize = sampleFormatToSerializedSize[sampleFormatId];
const result = new Uint8Array(serializedSize);
writeAscii(result, 'fmt ', 0); // + 4
writeUint32LE(result, serializedSize - 8, 4); // + 4
writeUint16LE(result, sampleFormatId, 8); // + 2
writeUint16LE(result, this.channelCount, 10); // + 2
writeUint32LE(result, this.sampleRate, 12); // + 4
writeUint32LE(result, this.byteRate, 16); // + 4
writeUint16LE(result, this.blockAlign, 20); // + 2
writeUint16LE(result, this.bitDepth, 22); // + 2
if (useExtensibleFormat) {
writeUint16LE(result, serializedSize - 26, 24); // + 2 (extension size)
writeUint16LE(result, this.bitDepth, 26); // + 2 (valid bits per sample)
writeUint32LE(result, this.speakerPositionMask, 28); // + 2 (speaker position mask)
if (this.guid) {
result.set(decodeHex(this.guid), 32);
}
else {
throw new Error(`Extensible format is not supported for sample format ${this.sampleFormat}`);
}
}
return result;
}
static deserializeFrom(formatChunkBody) {
let sampleFormat = readUint16LE(formatChunkBody, 0); // + 2
const channelCount = readUint16LE(formatChunkBody, 2); // + 2
const sampleRate = readUint32LE(formatChunkBody, 4); // + 4
const bitDepth = readUint16LE(formatChunkBody, 14);
let speakerPositionMask = 0;
if (sampleFormat === 65534) {
if (formatChunkBody.length < 40) {
throw new Error(`Format subchunk specifies a format id of 65534 (extensible) but its body size is ${formatChunkBody.length} bytes, which is smaller than the minimum expected of 40 bytes`);
}
speakerPositionMask = readUint16LE(formatChunkBody, 20);
const guid = encodeHex(formatChunkBody.subarray(24, 40));
if (guid === sampleFormatToGuid[SampleFormat.PCM]) {
sampleFormat = SampleFormat.PCM;
}
else if (guid === sampleFormatToGuid[SampleFormat.Float]) {
sampleFormat = SampleFormat.Float;
}
else if (guid === sampleFormatToGuid[SampleFormat.Alaw]) {
sampleFormat = SampleFormat.Alaw;
}
else if (guid === sampleFormatToGuid[SampleFormat.Mulaw]) {
sampleFormat = SampleFormat.Mulaw;
}
else {
throw new Error(`Unsupported format GUID in extended format subchunk: ${guid}`);
}
}
if (sampleFormat === SampleFormat.PCM) {
if (bitDepth !== 8 && bitDepth !== 16 && bitDepth !== 24 && bitDepth !== 32) {
throw new Error(`PCM audio has a bit depth of ${bitDepth}, which is not supported`);
}
}
else if (sampleFormat === SampleFormat.Float) {
if (bitDepth !== 32 && bitDepth !== 64) {
throw new Error(`IEEE float audio has a bit depth of ${bitDepth}, which is not supported`);
}
}
else if (sampleFormat === SampleFormat.Alaw) {
if (bitDepth !== 8) {
throw new Error(`Alaw audio has a bit depth of ${bitDepth}, which is not supported`);
}
}
else if (sampleFormat === SampleFormat.Mulaw) {
if (bitDepth !== 8) {
throw new Error(`Mulaw audio has a bit depth of ${bitDepth}, which is not supported`);
}
}
else {
throw new Error(`Wave audio format id ${sampleFormat} is not supported`);
}
return new WaveFormatHeader(channelCount, sampleRate, bitDepth, sampleFormat, speakerPositionMask);
}
}
export var SampleFormat;
(function (SampleFormat) {
SampleFormat[SampleFormat["PCM"] = 1] = "PCM";
SampleFormat[SampleFormat["Float"] = 3] = "Float";
SampleFormat[SampleFormat["Alaw"] = 6] = "Alaw";
SampleFormat[SampleFormat["Mulaw"] = 7] = "Mulaw";
})(SampleFormat || (SampleFormat = {}));
const sampleFormatToSerializedSize = {
[SampleFormat.PCM]: 24,
[SampleFormat.Float]: 26,
[SampleFormat.Alaw]: 26,
[SampleFormat.Mulaw]: 26,
65534: 48
};
const sampleFormatToGuid = {
[SampleFormat.PCM]: '0100000000001000800000aa00389b71',
[SampleFormat.Float]: '0300000000001000800000aa00389b71',
[SampleFormat.Alaw]: '0600000000001000800000aa00389b71',
[SampleFormat.Mulaw]: '0700000000001000800000aa00389b71',
};
//# sourceMappingURL=WaveFormatHeader.js.map