libsamplerate-js is a port of libsamplerate to Web Assembly exposed through a simple JS API for use in-browser or node. The simple API is ideal for resampling large pieces of audio. The full API is ideal for quickly resampling small portions (128+ samples) of a larger piece of audio such as audio received from a Websocket or WebRTC connection.
- works both in-browser and in node!
- 1-128 channels
- 1-192000 sample rates
- libsamplerate Full and Simple APIs
- See the libsamplerate docs for much more (and better) info
Install using NPM:
npm i @alexanderolsen/libsamplerate-jsSee Usage or API for more examples and instructions.
libsamplerate-js expects to receive Float32Array mono or multi-channel interleaved data, where each sample is -1 < sample < 1.
import { create, ConverterType } from "@alexanderolsen/libsamplerate-js";
let converterType = ConverterType.SRC_SINC_BEST_QUALITY;
let nChannels = 2;
let inputSampleRate = 44100;
let outputSampleRate = 48000;
create(nChannels, inputSampleRate, outputSampleRate, {
converterType: converterType, // default SRC_SINC_FASTEST. see API for more
}).then((src) => {
let data = new Float32Array(44100);
let resampledData = src.simple(data);
src.destroy(); // clean up
});or
const LibSampleRate = require("@alexanderolsen/libsamplerate-js");
let converterType = LibSampleRate.ConverterType.SRC_SINC_BEST_QUALITY;
let nChannels = 2;
let inputSampleRate = 44100;
let outputSampleRate = 48000;
LibSampleRate.create(nChannels, inputSampleRate, outputSampleRate, {
converterType: converterType, // default SRC_SINC_FASTEST. see API for more
}).then((src) => {
let data = new Float32Array(44100);
let resampledData = src.full(data);
src.destroy(); // clean up
});<script src="https://cdn.jsdelivr.net/npm/@alexanderolsen/libsamplerate-js"></script>
<script>
var converterType = LibSampleRate.ConverterType.SRC_SINC_BEST_QUALITY;
var nChannels = 2;
var inputSampleRate = 44100;
var outputSampleRate = 48000;
LibSampleRate.create(nChannels, inputSampleRate, outputSampleRate, {
converterType: converterType, // default SRC_SINC_FASTEST. see API for more
}).then((src) => {
var data = new Float32Array(44100);
let resampledData = src.full(data);
src.destroy(); // clean up
});
</script>Or use the libsamplerate.js file in the dist folder:
<script src="libsamplerate.js"></script>Once you've created the JS wrapper using create() or LibSampleRate.create(), the returned object exposes:
/**
* Calls the libsamplerate `simple` API. This should be used when resampling one individual chunk of audio,
* and no more calls to are required. If more calls are required, use the `full` API. If the array submitted
* is > 4MB, audio will be broken up into chunks and the `full` API will be used
*
* More (and better) info available at: http://www.mega-nerd.com/SRC/api_simple.html
*
* @param {Float32Array} dataIn Float32Array containing mono|interleaved audio data where -1 < dataIn[i] < 1
* @return {Float32Array} The resampled data
*/
simple(dataIn) { ... }/**
* Calls the libsamplerate `full` API. This should be used when resampling several chunks of the
* sample audio, e.g. receiving a live stream from WebRTC/websocket API.
*
* More (and better) info available at: http://www.mega-nerd.com/SRC/api_full.html
*
* @param {Float32Array} dataIn Float32Array containing mono|interleaved audio data where -1 < dataIn[i] < 1
* @param {Float32Array || null} dataOut Optionally, pass a Float32Array to avoid allocating an extra array for every esampling operation
* @return {Float32Array} The resampled data. If dataOut != null, dataOut is returned
*/
full(dataIn, dataOut=null) { ... }/**
* Cleans up WASM SRC resources. Once this is called on an instance, that instance must be
* reinitialized with src.init() before it can be used again.
*/
destroy() { ... }let nChannels = 2;
let inputSampleRate = 44100;
let outputSampleRate = 48000;
create(nChannels, inputSampleRate, outputSampleRate).then((src) => {
let data = new Float32Array(44100);
let resampled48k = src.simple(data); // returns ~48000 samples
src.outputSampleRate = 96000;
let resampled96k = src.simple(data); // returns ~96000 samples
});Converter types are as follows. More information can be found at the libsamplerate website.
const ConverterType = {
SRC_SINC_BEST_QUALITY: 0, // highest quality, slowest
SRC_SINC_MEDIUM_QUALITY: 1, //
SRC_SINC_FASTEST: 2, // in-between
SRC_ZERO_ORDER_HOLD: 3, // poor quality, "blindingly" fast
SRC_LINEAR: 4, // poor quality, "blindingly" fast
};cd libsamplerate-js/examples/cli
node index.js 48000 result.wavand listen to to the result
Run any server (http-server, etc) from the project directory:
cd libsamplerate-js
http-serverand visit localhost:8080/examples/basic or localhost:8080/examples/worker in a browser. Examples and benchmarks must be hosted from the root directory, as they need to access the files in dist.
Get a sense of how long resampling operations take in your environment:
cd libsamplerate-js
http-serverand visit localhost:8080/benchmarks. A minimalistic UI is provided to test different batch sizes, APIs, sample rates, and ConverterTypes.
Before you can compile the WASM code you need to download and install Empscripten and activate PATH variables for the current terminal. To build and compile the JS + WASM resources from source, run:
git clone https://github.com/aolsenjazz/libsamplerate-js
cd libsamplerate-js
npm i
npm run compile-wasm
npm run buildYou can also build with docker (either from scratch or the wasm only):
git clone https://github.com/aolsenjazz/libsamplerate-js
cd libsamplerate-js
git submodule update --init
cd scripts/library/
docker build -t gcc-emscripten .
cd ../../
npm run compile-library-docker
npm run compile-wasm-docker
npm run buildProduction files are placed in the dist directory.
Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.
Licenses are available in LICENSE.md.