music-metadata/lib/ogg/flac/FlacStream.js

Music metadata parser for Node.js, supporting virtual any audio and tag format.

import initDebug from 'debug';
import * as Flac from '../../flac/FlacToken.js';
import { FlacParser } from '../../flac/FlacParser.js';
import { FourCcToken } from '../../common/FourCC.js';
import { VorbisPictureToken } from '../vorbis/Vorbis.js';
const debug = initDebug('music-metadata:parser:ogg:theora');
/**
 * Ref:
 * - https://xiph.org/flac/ogg_mapping.html
 */
export class FlacStream {
    constructor(metadata, options, tokenizer) {
        this.durationOnLastPage = false;
        this.metadata = metadata;
        this.options = options;
        this.tokenizer = tokenizer;
        this.flacParser = new FlacParser(this.metadata, this.tokenizer, options);
    }
    /**
     * Vorbis 1 parser
     * @param header Ogg Page Header
     * @param pageData Page data
     */
    async parsePage(header, pageData) {
        if (header.headerType.firstPage) {
            await this.parseFirstPage(header, pageData);
        }
    }
    calculateDuration() {
        debug('duration calculation not implemented');
    }
    /**
     * Parse first Theora Ogg page. the initial identification header packet
     */
    async parseFirstPage(_header, pageData) {
        debug('First Ogg/FLAC page');
        const fourCC = await FourCcToken.get(pageData, 9);
        if (fourCC.toString() !== 'fLaC') {
            throw new Error('Invalid FLAC preamble');
        }
        const blockHeader = await Flac.BlockHeader.get(pageData, 13);
        await this.parseDataBlock(blockHeader, pageData.subarray(13 + Flac.BlockHeader.len));
    }
    async parseDataBlock(blockHeader, pageData) {
        debug(`blockHeader type=${blockHeader.type}, length=${blockHeader.length}`);
        switch (blockHeader.type) {
            case Flac.BlockType.STREAMINFO: {
                const streamInfo = Flac.BlockStreamInfo.get(pageData, 0);
                return this.flacParser.processsStreamInfo(streamInfo);
            }
            case Flac.BlockType.PADDING:
                break;
            case Flac.BlockType.APPLICATION:
                break;
            case Flac.BlockType.SEEKTABLE:
                break;
            case Flac.BlockType.VORBIS_COMMENT:
                return this.flacParser.parseComment(pageData);
            case Flac.BlockType.PICTURE:
                if (!this.options.skipCovers) {
                    const picture = new VorbisPictureToken(pageData.length).get(pageData, 0);
                    return this.flacParser.addPictureTag(picture);
                }
                break;
            default:
                this.metadata.addWarning(`Unknown block type: ${blockHeader.type}`);
        }
        // Ignore data block
        return this.tokenizer.ignore(blockHeader.length).then();
    }
    flush() {
        return Promise.resolve();
    }
}