recorderx

Record and export audio in the browser via WebRTC api.

Support output raw, pcm and wav format.

Support Typescript.

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Demo

Install

NPM

npm install recorderx --sava

Yarn

yarn add recorderx

Quick Start

import Recorderx, { ENCODE_TYPE } from "recorderx";

const rc = new Recorderx();

// start recorderx
rc.start()
  .then(() => {
    console.log("start recording");
  })
  .catch(error => {
    console.log("Recording failed.", error);
  });

// pause recorderx
rc.pause();

// get wav, a Blob
var wav = rc.getRecord({
  encodeTo: ENCODE_TYPE.WAV,
  compressible: true
});

// get wav, but disable compression
var wav = rc.getRecord({
  encodeTo: ENCODE_TYPE.WAV
});

Usage

Recorderx constructor

Creates a recorderx instance

• recordable: boolean

  Whether to support continuous recording, default to true.

• sampleRate: number

  Wav sampling rate, default to 16000.

• sampleBits: number

  Wav sampling bits, default to 16.

  Optional value: 16 or 8

• bufferSize: number

  The buffer size in units of sample-frames, default to 16384.

  Optional value: 256, 512, 1024, 2048, 4096, 8192, 16384.

interface RecorderxConstructorOptions {
  recordable?: boolean
  bufferSize?: number
  sampleRate?: number
  sampleBits?: number
}

constructor ({ recordable, bufferSize, sampleRate, sampleBits }?: RecorderxConstructorOptions)

Recorderx property

recorder state

enum RECORDER_STATE {
  READY,
  RECORDING
}

readonly state: RECORDER_STATE

AudioContext instance

readonly ctx: AudioContext

Recorderx methods

start recording

audioprocessCallback: The onaudioprocess event handler of the ScriptProcessorNode, refer to MDN

data: current frame audio data

You can do special processing on the audio data of each frame in this callback function

start (audioprocessCallback?: (data: Float32Array) => any): Promise<MediaStream>

pause recording

pause (): void

clear recording buffer

clear (): void

get recording data

Support for exporting WAV, PCM, RAW

• encodeTo: ENCODE_TYPE

  Export format, default to RAW.

• compressible: boolean

  Whether to enable compression, default to false.

  • If compression is enabled, the exported WAV, PCM, RAW will be compressed data, and the audio sample rate is the sampleRate passed in when the Recorderx is instantiated.

  • If compression is enabled, the exported WAV, PCM, RAW will be compressed data, and the audio sample rate is the sampleRate passed in when the Recorderx is instantiated.

  • The compression algorithm is based on linear extraction and is distorted at some sample rates.

enum ENCODE_TYPE {
  RAW = 'raw',
  PCM = 'pcm',
  WAV = 'wav'
}

/**
 * Get RAW recording data.
 */
getRecord ({ encodeTo, compressible }?: { encodeTo?: ENCODE_TYPE.RAW, compressible?: boolean }): Float32Array

/**
 * Get PCM recording data.
 */
getRecord ({ encodeTo, compressible }?: { encodeTo?: ENCODE_TYPE.PCM, compressible?: boolean }): ArrayBuffer

/**
 * Get WAV recording data.
 */
getRecord ({ encodeTo, compressible }?: { encodeTo?: ENCODE_TYPE.WAV, compressible?: boolean }): Blob

Audio Tools

import { audioTools } from "Recorderx";

/*
audioTools.merge();
audioTools.compress();
audioTools.encodeToPCM();
audioTools.encodeToWAV();
*/

Merge Float32Array

function merge(bufferList: Array<Float32Array>, length: number): Float32Array;

Compress Float32Array

function compress(
  buffer: Float32Array,
  inputSampleRate: number,
  outputSampleRate: number
): Float32Array;

Convert to PCM

function encodeToPCM(bytes: Float32Array, sampleBits: number): ArrayBuffer;

Convert to WAV

function encodeToWAV(
  bytes: Float32Array,
  sampleBits: number,
  sampleRate: number
): Blob;

Browser Support

All browsers that implement getUserMedia.

WeChat browser is not supported, only Safari is supported under IOS.

For details, please refer to MDN

License

MIT

Else

Audio compression and conversion to wav method reference from recording.