49 lines
1.8 KiB
JavaScript
49 lines
1.8 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.Common = void 0;
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const Token = require("token-types");
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const FourCC_1 = require("../common/FourCC");
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class Common {
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constructor(header, isAifc) {
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this.isAifc = isAifc;
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const minimumChunkSize = isAifc ? 22 : 18;
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if (header.chunkSize < minimumChunkSize)
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throw new Error(`COMMON CHUNK size should always be at least ${minimumChunkSize}`);
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this.len = header.chunkSize;
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}
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get(buf, off) {
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// see: https://cycling74.com/forums/aiffs-80-bit-sample-rate-value
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const shift = buf.readUInt16BE(off + 8) - 16398;
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const baseSampleRate = buf.readUInt16BE(off + 8 + 2);
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const res = {
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numChannels: buf.readUInt16BE(off),
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numSampleFrames: buf.readUInt32BE(off + 2),
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sampleSize: buf.readUInt16BE(off + 6),
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sampleRate: shift < 0 ? baseSampleRate >> Math.abs(shift) : baseSampleRate << shift
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};
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if (this.isAifc) {
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res.compressionType = FourCC_1.FourCcToken.get(buf, off + 18);
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if (this.len > 22) {
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const strLen = buf.readInt8(off + 22);
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if (strLen > 0) {
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const padding = (strLen + 1) % 2;
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if (23 + strLen + padding === this.len) {
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res.compressionName = new Token.StringType(strLen, 'binary').get(buf, off + 23);
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}
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else {
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throw new Error('Illegal pstring length');
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}
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}
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else {
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res.compressionName = undefined;
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}
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}
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}
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else {
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res.compressionName = 'PCM';
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}
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return res;
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}
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}
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exports.Common = Common;
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