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Implement MP3 demuxer

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This commit is contained in:
Vanilagy
2025-01-26 10:01:09 +01:00
parent 387c4dc525
commit 7205d9445b
6 changed files with 464 additions and 25 deletions
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src/wave/wave-demuxer.ts
+24 -24
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@@ -17,7 +17,7 @@ export enum WaveFormat {
}
export class WaveDemuxer extends Demuxer {
riffReader: RiffReader;
metadataReader: RiffReader;
chunkReader: RiffReader;
metadataPromise: Promise<void> | null = null;
@@ -36,38 +36,38 @@ export class WaveDemuxer extends Demuxer {
constructor(input: Input) {
super(input);
this.riffReader = new RiffReader(input._mainReader);
this.metadataReader = new RiffReader(input._mainReader);
this.chunkReader = new RiffReader(new Reader(input._source, 64 * 2 ** 20));
}
async readMetadata() {
return this.metadataPromise ??= (async () => {
const riffType = this.riffReader.readAscii(4);
this.riffReader.littleEndian = riffType === 'RIFF';
const riffType = this.metadataReader.readAscii(4);
this.metadataReader.littleEndian = riffType === 'RIFF';
const totalFileSize = this.riffReader.readU32() + 8;
const format = this.riffReader.readAscii(4);
const totalFileSize = this.metadataReader.readU32() + 8;
const format = this.metadataReader.readAscii(4);
if (format !== 'WAVE') {
throw new Error('Invalid WAVE file - wrong format');
}
this.riffReader.pos = 12;
while (this.riffReader.pos < totalFileSize) {
await this.riffReader.reader.loadRange(this.riffReader.pos, this.riffReader.pos + 8);
this.metadataReader.pos = 12;
while (this.metadataReader.pos < totalFileSize) {
await this.metadataReader.reader.loadRange(this.metadataReader.pos, this.metadataReader.pos + 8);
const chunkId = this.riffReader.readAscii(4);
const chunkSize = this.riffReader.readU32();
const startPos = this.riffReader.pos;
const chunkId = this.metadataReader.readAscii(4);
const chunkSize = this.metadataReader.readU32();
const startPos = this.metadataReader.pos;
if (chunkId === 'fmt ') {
await this.parseFmtChunk(chunkSize);
} else if (chunkId === 'data') {
this.dataStart = this.riffReader.pos;
this.dataStart = this.metadataReader.pos;
this.dataSize = chunkSize;
}
this.riffReader.pos = startPos + chunkSize + (chunkSize & 1); // Handle padding
this.metadataReader.pos = startPos + chunkSize + (chunkSize & 1); // Handle padding
}
if (!this.audioInfo) {
@@ -85,32 +85,32 @@ export class WaveDemuxer extends Demuxer {
}
private async parseFmtChunk(size: number) {
await this.riffReader.reader.loadRange(this.riffReader.pos, this.riffReader.pos + size);
await this.metadataReader.reader.loadRange(this.metadataReader.pos, this.metadataReader.pos + size);
let formatTag = this.riffReader.readU16();
const numChannels = this.riffReader.readU16();
const sampleRate = this.riffReader.readU32();
this.riffReader.pos += 4;
const blockAlign = this.riffReader.readU16();
let formatTag = this.metadataReader.readU16();
const numChannels = this.metadataReader.readU16();
const sampleRate = this.metadataReader.readU32();
this.metadataReader.pos += 4;
const blockAlign = this.metadataReader.readU16();
let bitsPerSample: number;
if (size === 14) { // Plain WAVEFORMAT
bitsPerSample = 8;
} else {
bitsPerSample = this.riffReader.readU16();
bitsPerSample = this.metadataReader.readU16();
}
// Handle WAVEFORMATEXTENSIBLE
if (size >= 18 && formatTag !== 0x0165) {
const cbSize = this.riffReader.readU16();
const cbSize = this.metadataReader.readU16();
const remainingSize = size - 18;
const extensionSize = Math.min(remainingSize, cbSize);
if (extensionSize >= 22 && formatTag === WaveFormat.EXTENSIBLE) {
// Parse WAVEFORMATEXTENSIBLE
this.riffReader.pos += 2 + 4;
const subFormat = this.riffReader.readBytes(16);
this.metadataReader.pos += 2 + 4;
const subFormat = this.metadataReader.readBytes(16);
// Get actual format from subFormat GUID
formatTag = subFormat[0]! | (subFormat[1]! << 8);