77 lines
3.1 KiB
JavaScript
77 lines
3.1 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.WavPack = 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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const SampleRates = [6000, 8000, 9600, 11025, 12000, 16000, 22050, 24000, 32000, 44100,
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48000, 64000, 88200, 96000, 192000, -1];
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class WavPack {
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static isBitSet(flags, bitOffset) {
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return WavPack.getBitAllignedNumber(flags, bitOffset, 1) === 1;
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}
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static getBitAllignedNumber(flags, bitOffset, len) {
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return (flags >>> bitOffset) & (0xffffffff >>> (32 - len));
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}
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}
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/**
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* WavPack Block Header
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*
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* 32-byte little-endian header at the front of every WavPack block
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*
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* Ref: http://www.wavpack.com/WavPack5FileFormat.pdf (page 2/6: 2.0 "Block Header")
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*/
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WavPack.BlockHeaderToken = {
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len: 32,
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get: (buf, off) => {
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const flags = Token.UINT32_LE.get(buf, off + 24);
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const res = {
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// should equal 'wvpk'
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BlockID: FourCC_1.FourCcToken.get(buf, off),
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// 0x402 to 0x410 are valid for decode
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blockSize: Token.UINT32_LE.get(buf, off + 4),
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// 0x402 (1026) to 0x410 are valid for decode
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version: Token.UINT16_LE.get(buf, off + 8),
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// 40-bit total samples for entire file (if block_index == 0 and a value of -1 indicates an unknown length)
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totalSamples: /* replace with bigint? (Token.UINT8.get(buf, off + 11) << 32) + */ Token.UINT32_LE.get(buf, off + 12),
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// 40-bit block_index
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blockIndex: /* replace with bigint? (Token.UINT8.get(buf, off + 10) << 32) + */ Token.UINT32_LE.get(buf, off + 16),
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// 40-bit total samples for entire file (if block_index == 0 and a value of -1 indicates an unknown length)
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blockSamples: Token.UINT32_LE.get(buf, off + 20),
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// various flags for id and decoding
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flags: {
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bitsPerSample: (1 + WavPack.getBitAllignedNumber(flags, 0, 2)) * 8,
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isMono: WavPack.isBitSet(flags, 2),
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isHybrid: WavPack.isBitSet(flags, 3),
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isJointStereo: WavPack.isBitSet(flags, 4),
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crossChannel: WavPack.isBitSet(flags, 5),
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hybridNoiseShaping: WavPack.isBitSet(flags, 6),
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floatingPoint: WavPack.isBitSet(flags, 7),
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samplingRate: SampleRates[WavPack.getBitAllignedNumber(flags, 23, 4)],
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isDSD: WavPack.isBitSet(flags, 31)
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},
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// crc for actual decoded data
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crc: new Token.Uint8ArrayType(4).get(buf, off + 28)
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};
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if (res.flags.isDSD) {
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res.totalSamples *= 8;
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}
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return res;
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}
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};
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/**
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* 3.0 Metadata Sub-Blocks
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* Ref: http://www.wavpack.com/WavPack5FileFormat.pdf (page 4/6: 3.0 "Metadata Sub-Block")
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*/
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WavPack.MetadataIdToken = {
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len: 1,
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get: (buf, off) => {
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return {
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functionId: WavPack.getBitAllignedNumber(buf[off], 0, 6),
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isOptional: WavPack.isBitSet(buf[off], 5),
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isOddSize: WavPack.isBitSet(buf[off], 6),
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largeBlock: WavPack.isBitSet(buf[off], 7)
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};
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}
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};
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exports.WavPack = WavPack;
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