music-metadata
Version:
Music metadata parser for Node.js, supporting virtual any audio and tag format.
57 lines • 3.02 kB
JavaScript
import initDebug from 'debug';
import { AbstractID3Parser } from '../id3v2/AbstractID3Parser.js';
import { ChunkHeader, DsdChunk, FormatChunk } from './DsfChunk.js';
import { ID3v2Parser } from "../id3v2/ID3v2Parser.js";
import { makeUnexpectedFileContentError } from '../ParseError.js';
const debug = initDebug('music-metadata:parser:DSF');
export class DsdContentParseError extends makeUnexpectedFileContentError('DSD') {
}
/**
* DSF (dsd stream file) File Parser
* Ref: https://dsd-guide.com/sites/default/files/white-papers/DSFFileFormatSpec_E.pdf
*/
export class DsfParser extends AbstractID3Parser {
async postId3v2Parse() {
const p0 = this.tokenizer.position; // mark start position, normally 0
const chunkHeader = await this.tokenizer.readToken(ChunkHeader);
if (chunkHeader.id !== 'DSD ')
throw new DsdContentParseError('Invalid chunk signature');
this.metadata.setFormat('container', 'DSF');
this.metadata.setFormat('lossless', true);
const dsdChunk = await this.tokenizer.readToken(DsdChunk);
if (dsdChunk.metadataPointer === BigInt(0)) {
debug("No ID3v2 tag present");
}
else {
debug(`expect ID3v2 at offset=${dsdChunk.metadataPointer}`);
await this.parseChunks(dsdChunk.fileSize - chunkHeader.size);
// Jump to ID3 header
await this.tokenizer.ignore(Number(dsdChunk.metadataPointer) - this.tokenizer.position - p0);
return new ID3v2Parser().parse(this.metadata, this.tokenizer, this.options);
}
}
async parseChunks(bytesRemaining) {
while (bytesRemaining >= ChunkHeader.len) {
const chunkHeader = await this.tokenizer.readToken(ChunkHeader);
debug(`Parsing chunk name=${chunkHeader.id} size=${chunkHeader.size}`);
switch (chunkHeader.id) {
case 'fmt ': {
const formatChunk = await this.tokenizer.readToken(FormatChunk);
this.metadata.setFormat('numberOfChannels', formatChunk.channelNum);
this.metadata.setFormat('sampleRate', formatChunk.samplingFrequency);
this.metadata.setFormat('bitsPerSample', formatChunk.bitsPerSample);
this.metadata.setFormat('numberOfSamples', formatChunk.sampleCount);
this.metadata.setFormat('duration', Number(formatChunk.sampleCount) / formatChunk.samplingFrequency);
const bitrate = formatChunk.bitsPerSample * formatChunk.samplingFrequency * formatChunk.channelNum;
this.metadata.setFormat('bitrate', bitrate);
return; // We got what we want, stop further processing of chunks
}
default:
this.tokenizer.ignore(Number(chunkHeader.size) - ChunkHeader.len);
break;
}
bytesRemaining -= chunkHeader.size;
}
}
}
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