wavefile

wavefile

Read & write wave files with 4, 8, 16, 24, 32 & 64-bit data.
Copyright (c) 2017-2018 Rafael da Silva Rocha.
https://github.com/rochars/wavefile

About

wavefile is a module to work with wav files. It is partly inspired by SoX and intended to run in both Node.js and the browser.

With wavefile you can:

• Create wav files from scratch
• Read existing wav files
• Encode/decode files as ADPCM, A-Law and mu-Law
• Read/write the data in a wav file header
• Turn RIFF files to RIFX and RIFX files to RIFF
• Edit BWF metada ("bext" chunk)

And more.

wavefile is extensively tested and contains samples of all supported formats. Please note that some formats (like 8-bit A-Law and 64-bit floating point) are not widely supported and may not load in every player.

Install

npm install wavefile

See it in action

https://tr2099.github.io/

Hit "Load in player" to generate wave files.

This website uses wavefile to create the files. The effects are provided by other libraries.

Some bit depths may not be supported by your browser, like 32-bit floating point or 64-bit floating point.

Use

let fs = require("fs");
let Wavefile = require("wavefile");

let wav = new Wavefile(fs.readFileSync("file.wav"));
console.log(wav.chunkId);
console.log(wav.chunkSize);
console.log(wav.fmtChunkId);
fs.writeFileSync(path, wav.toBuffer());

Create wave files from scratch

You must inform the number of channels, the sample rate, the bit depth and the samples (in this order). The samples are an array of numbers. The array may be multidimensional if there is more than one channel.

Possible values for the bit depth are:
"4" - 4-bit IMA-ADPCM
"8" - 8-bit
"8a" - 8-bit A-Law
"8m" - 8-bit mu-Law
"16" - 16-bit
"24" - 24-bit
"32" - 32-bit
"32f" - 32-bit floating point
"64" - 64-bit floating point

let wav = new WaveFile();

// Create a mono wave file, 44.1 kHz, 32-bit and 4 samples
wav.fromScratch(1, 44100, '32', [0, -2147483648, 2147483647, 4]);
fs.writeFileSync(path, wav.toBuffer());

// stereo, 48 kHz, 8-bit
// samples are de-interleaved
wav.fromScratch(2, 48000, '8', [
    [0, -2, 4, 3],
    [0, -1, 4, 3]
]);
// Interleaving the samples
wav.interleave();
fs.writeFileSync(path, wav.toBuffer());

// Default is RIFF. To create RIFX files:
wav.fromScratch(1, 44100, '32', samples, {"container": "RIFX"});
fs.writeFileSync(path, wav.toBuffer());

Interleave and de-interleave stereo samples

// Interleave stereo samples
wav.interleave();

// De-interleave the samples into multiple channels
wav.deInterleave();

RIFF to RIFX and RIFX to RIFF

// Turn a RIFF file to a RIFX file
wav.toRIFX();

// Turn a RIFX file to a RIFF file
wav.toRIFF();

IMA-ADPCM

16-bit 8000 Hz wave files can be compressed as IMA-ADPCM:

// Encode a 16-bit wave file as 4-bit IMA-ADPCM:
wav.toIMAADPCM();

To decode 4-bit IMA-ADPCM as 16-bit linear PCM:

// Decode 4-bit IMA-ADPCM as 16-bit:
wav.fromIMAADPCM();

IMA-ADPCM files compressed with wavefile will have a block align of 256 bytes.

wavefile also assumes a block align of 256 bytes when decoding IMA-ADPCM files, but you can also decode files with a different block align:

// Decode a 4-bit IMA-ADPCM with block align of 1024 bytes:
wav.fromIMAADPCM(1024);

A-Law

16-bit wave files can be encoded as A-Law:

// Encode a 16-bit wave file as 8-bit A-law:
wav.toALaw();

To decode 8-bit A-Law as 16-bit linear PCM:

// Decode 8-bit A-Law as 16-bit:
wav.fromALaw();

mu-Law

16-bit wave files can be encoded as mu-Law:

// Encode a 16-bit wave file as 8-bit mu-law:
wav.toMuLaw();

To decode 8-bit mu-Law as 16-bit linear PCM:

// Decode 8-bit mu-Law as 16-bit:
wav.fromMuLaw();

Change the bit depth

Currently there is no dithering when changing the bit depth.

If the samples are stereo they need to be interleaved before changing the bit depth.

Notice that you can't change to and from 4-bit ADPCM, 8-bit A-Law and 8-bit mu-Law. To encode/decode files as ADPCM, A-Law and mu-Law you must use the toIMAADPCM(), fromIMAADPCM(), toALaw(), fromALaw(), toMuLaw() and fromMuLaw() methods. Only 16-bit samples can be encoded, and decoding always result in 16-bit samples.

let wav = new Wavefile(fs.readFileSync("file.wav"));

// Possible values are:
//  "8", "16", "24", "32", "32f", "64"
wav.toBitDepth("24");

The properties

let wav = new Wavefile(fs.readFileSync("file.wav"));

// The container, "RIFF" or "RIFX"
console.log(wav.chunkId);
console.log(wav.chunkSize);
console.log(wav.format); // WAVE

// "fmt "
console.log(wav.fmtChunkId);
console.log(wav.fmtChunkSize);
console.log(wav.audioFormat);
console.log(wav.numChannels);
console.log(wav.sampleRate);
console.log(wav.byteRate);
console.log(wav.blockAlign);
console.log(wav.bitsPerSample);
console.log(wav.cbSize);
console.log(wav.validBitsPerSample);

// "fact"
console.log(wav.factChunkId);
console.log(wav.factChunkSize);
console.log(wav.dwSampleLength);

// "bext"
console.log(wav.bextChunkFields);

// "data"
console.log(wav.dataChunkId);
console.log(wav.dataChunkSize);

// array of numbers
console.log(wav.samples);

BWF data

BWF data ("bext" chunk) is stored in the bextChunkFields property in human-readable form.

wav.bextChunkFields = {
    "description": "", // 256 chars
    "originator": "", // 32 chars
    "originatorReference": "", // 32 chars
    "originationDate": "", // 10 chars
    "originationTime": "", // 8 chars
    "timeReference": "", // 64-bit value kept as an array of 8 bytes
    "version": "", // 16-bit number
    "UMID": "", // 64 chars
    "loudnessValue": "", // 16-bit number
    "loudnessRange": "", // 16-bit number
    "maxTruePeakLevel": "", // 16-bit number
    "maxMomentaryLoudness": "", // 16-bit number
    "maxShortTermLoudness": "", // 16-bit number
    "reserved": "", // 180 chars
    "codingHistory": "" // string, unlimited size
};

The samples

Range:

• 0 to 255 for 8-bit
• -32768 to 32767 for 16-bit
• -8388608 to 8388607 for 24-bit
• -2147483648 to 2147483647 for 32-bit
• -1.0 to 1.0 for 32-bit (float)
• -1.0 to 1.0 for 64-bit (float)

LICENSE

Copyright (c) 2017-2018 Rafael da Silva Rocha.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.