47 lines
2.3 KiB
JavaScript
47 lines
2.3 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.MpcSv7Parser = void 0;
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const debug_1 = require("debug");
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const BasicParser_1 = require("../../common/BasicParser");
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const APEv2Parser_1 = require("../../apev2/APEv2Parser");
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const BitReader_1 = require("./BitReader");
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const SV7 = require("./StreamVersion7");
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const debug = (0, debug_1.default)('music-metadata:parser:musepack');
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class MpcSv7Parser extends BasicParser_1.BasicParser {
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constructor() {
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super(...arguments);
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this.audioLength = 0;
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}
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async parse() {
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const header = await this.tokenizer.readToken(SV7.Header);
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if (header.signature !== 'MP+')
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throw new Error('Unexpected magic number');
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debug(`stream-version=${header.streamMajorVersion}.${header.streamMinorVersion}`);
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this.metadata.setFormat('container', 'Musepack, SV7');
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this.metadata.setFormat('sampleRate', header.sampleFrequency);
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const numberOfSamples = 1152 * (header.frameCount - 1) + header.lastFrameLength;
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this.metadata.setFormat('numberOfSamples', numberOfSamples);
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this.duration = numberOfSamples / header.sampleFrequency;
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this.metadata.setFormat('duration', this.duration);
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this.bitreader = new BitReader_1.BitReader(this.tokenizer);
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this.metadata.setFormat('numberOfChannels', header.midSideStereo || header.intensityStereo ? 2 : 1);
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const version = await this.bitreader.read(8);
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this.metadata.setFormat('codec', (version / 100).toFixed(2));
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await this.skipAudioData(header.frameCount);
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debug(`End of audio stream, switching to APEv2, offset=${this.tokenizer.position}`);
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return APEv2Parser_1.APEv2Parser.tryParseApeHeader(this.metadata, this.tokenizer, this.options);
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}
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async skipAudioData(frameCount) {
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while (frameCount-- > 0) {
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const frameLength = await this.bitreader.read(20);
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this.audioLength += 20 + frameLength;
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await this.bitreader.ignore(frameLength);
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}
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// last frame
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const lastFrameLength = await this.bitreader.read(11);
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this.audioLength += lastFrameLength;
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this.metadata.setFormat('bitrate', this.audioLength / this.duration);
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}
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}
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exports.MpcSv7Parser = MpcSv7Parser;
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