AMRPlayer

AMRPlayer is a modernized version of amr.js, supporting the loading and playback of AMR audio format.

amr.js has ceased updates, utilizing numerous global variables, lacking support for strict mode, not supporting modularity, and missing documentation.

This project has modernized it, supporting ES Module, CommonJS, and IIFE formats, compatible with modern build tools (such as Webpack, Rollup, Vite, etc.). It also adds playback control support and convenient data writing methods.

I used AMR audio interpretation in my project and found that there are not many libraries to choose from. Although amr.js lacks maintenance, it is still usable. Thanks to the original authors for their contributions, and thus I also share my achievements with everyone.

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Features

• Easy loading of AMR audio files.
• Provides audio playback control.
• Supports converting AMR audio to WAV format.
• Compatible with modern JavaScript build tools.
• No longer uses multiple global variables; modular environments do not require global variables, and only one global variable is exposed in the browser environment.

Installation

You can install AMRPlayer via npm:

npm install amrplayer

Import Methods

Depending on your project environment, you can choose any of the following methods to import AMRPlayer.

1. ES Module (Recommended)

If your project uses ES Module (e.g., Vite or modern browser environments), you can import it as follows:

import AMRPlayer from 'amrplayer';

// Using AMRPlayer
const amrplayer = new AMRPlayer();

2. CommonJS

If your project uses CommonJS, you can import it as follows:

const AMRPlayer = require('amrplayer');

// Using AMRPlayer
const amrplayer = new AMRPlayer();

3. Browser

If you are directly using the <script> tag in the browser, you can import it as follows:

<script src="https://unpkg.com/amrplayer/dist/amrplayer.js"></script>
<script>
    // AMRPlayer will be exposed as a global variable
    const amrplayer = new AMRPlayer();
</script>

Usage Examples

Initializing AMRPlayer

import AMRPlayer from 'amrplayer';

const amrplayer = new AMRPlayer();

Loading AMR Audio Files

Loading from ArrayBuffer

fetch('audio.amr')
   .then(response => response.arrayBuffer())
   .then(arrayBuffer => amrplayer.setBuffer(arrayBuffer));

Loading from Blob

<input type="file" name="file" id="file" accept=".amr">

const file = document.getElementById('file').files[0];
// Note that setBlob is an asynchronous interface
await amrplayer.setBlob(file);

Converting to WAV Format

Convenient for playback using <audio>.

<audio id="audio" controls></audio>

const url = amrplayer.getWAV();
document.getElementById('audio').src = url;

Audio Playback

const amraudio = amrplayer.getAudio(() => console.log('Audio playback ended'));

// Synchronous interface
amraudio.start(); // Start playback
amraudio.stop(); // Stop playback

// Asynchronous interface
amraudio.suspend(); // Pause playback
amraudio.resume(); // Resume playback
amraudio.toggle(); // Toggle playback state
amraudio.close(); // Close the audio context when amraudio is no longer needed

Audio State

console.log('Current audio state:', amraudio.state);

API Documentation

new AMRPlayer()

AMRPlayer.setBuffer(arrayBuffer)

Decodes the passed ArrayBuffer into Float32Array and sets it as the audio data.

• arrayBuffer: The ArrayBuffer to decode.
• Returns the decoded Float32Array.

AMRPlayer.setBlob(blob)

Converts the passed Blob into ArrayBuffer and sets it as the audio data.

• blob: The Blob to convert.
• Returns a Promise that resolves to the decoded Float32Array.

AMRPlayer.getAudio(onEnd)

Creates an AMRAudio instance and sets the callback function for when audio playback ends.

• onEnd: The callback function triggered when audio playback ends.
• Returns an AMRAudio instance.

AMRPlayer.getWAV()

Converts the current audio data to WAV format.

• Returns a base64 string: data:audio/wav;base64,...

AMRAudio Class

new AMRAudio(float32Array)

Creates an AMRAudio instance.

• float32Array: The Float32Array used to create the audio buffer.

AMRAudio.start()

Starts audio playback.

AMRAudio.stop()

Stops audio playback.

AMRAudio.close()

Closes the audio context. Asynchronous interface.

AMRAudio.suspend()

Suspends the audio context. Asynchronous interface.

AMRAudio.resume()

Resumes the audio context. Asynchronous interface.

AMRAudio.toggle()

Toggles the audio playback state, cycling through: play -> pause -> resume. Asynchronous interface.

AMRAudio.state

Gets the current audio playback state: 'stopped', 'running', 'suspended'.

AMRAudio.onEnd()

Automatically called when playback ends. Triggered by automatic end or calling AMRAudio.stop().

License

This project is open-sourced under the MIT license. For more details, please refer to the LICENSE file.