opus-decoder

opus-decoder

opus-decoder is a Web Assembly Opus audio decoder.

See the homepage of this repository for more Web Assembly audio decoders like this one.

Installing

Install via NPM.

Usage

1. Create a new instance and wait for the WASM to finish compiling.

   import {OpusDecoder} from 'opus-decoder';
   
   const decoder = new OpusDecoder();
   
   // wait for the WASM to be compiled
   await decoder.ready;
   

2. Begin decoding Opus frames.

   // Decode an individual Opus frame
   const {channelData, samplesDecoded, sampleRate} = decoder.decodeFrame(opusFrame);
   
   // Decode an array of individual Opus frames
   const {channelData, samplesDecoded, sampleRate} = decoder.decodeFrames(opusFrameArray);
   

3. When done decoding, free up the memory being used by the WASM module. You will need to create a new instance to start decoding again.

   decoder.free();
   

API

Getters

• decoder.ready
  • Returns a promise that is resolved when the WASM is compiled and ready to use.

Methods

Each method returns an object containing the decoded audio, number of samples decoded, and sample rate of the decoded audio.

The channelData contains the raw decoded PCM for each channel (left, and right). Each Float32Array can be used directly in the WebAudio api.

// decoded audio return value
{
    channelData: [leftAudio, rightAudio],
    samplesDecoded: 1234,
    sampleRate: 48000
}

• decoder.decodeFrame(opusFrame)
  • opusFrame Uint8Array containing a single Opus frame.
• decoder.decodeFrames(opusFrames)
  • opusFrames Array of Uint8Arrays containing Opus frames.