react-native-soundfont

Getting started

$ npm install react-native-soundfont react-native-sound --save

Usage

Example

import SoundFont from 'react-native-soundfont';

...
SoundFont.instrument('violin', {
  notes: ['C4', 'A3'] // only load 'C4' and 'A3' for speed
  gain: 1,
  release: 0.5 // release after half second
}).then(violin => {
  violin.play('C4', {gain: 0.5}); // Play 'C4' immediately at half gain
  violen.start('A3', 1000); // Start 'A3' after a second
  violin.stop('A3', 2000); // Stop after a second
  violin.destroy(); // release the Sound resources used (should be called, eventually)
});
...

Functions

The main API can be imported directly like import { instrument } from 'react-native-soundfont':

Function	Arguments	Returns	Description
instrument	name, options	Promise<Player>	Initializes player for specific instrument

Options:

{
  notes: ['A3','B3'], // list of all valid notes (there is a matching sound file). Defaults to all notes (A0->G8)
  path: Sound.MAIN_BUNDLE, // path to sound files. defaults to res/raw (assumes imported react-native-sound as Sound)
  ext: 'mp3', // sound file extension

  // Global Player options (applies to all start, stop functions unless overridden)
  gain: 1, // (volume)
  clip: 0, // second into sound to seek to before playing
  duration: undefined, // length to play before stopping (or undefined for full length)
  loop: false, // loop sound while key is pressed
  pan: 0.5, // left (0) to right (1)
  speed: 1 // speed of playback
  release: undefined, // time taken for the level to decay to zero after key is released (or undefined to play rest of sound)
}

Player

The following can be invoked on the Player object that is returned by instrument()

Function	Arguments	Returns	Description
start	note, when, options	Player	Starts note playback in when milliseconds
play	note, options	Player	Starts note now
stop	note, when, options	Player	Stops note playback in when milliseconds
destroy			Releases sound files for player

Options:

{
  gain: 1, // (volume)
  clip: 0, // second into sound to seek to before playing
  duration: undefined, // length to play before stopping (or undefined for full length)
  loop: false, // loop sound while key is pressed
  pan: 0.5, // left (0) to right (1)
  speed: 1 // speed of playback
  release: undefined, // time taken for the level to decay to zero after key is released (or undefined to play rest of sound)
}

Adding sounds

By default, MP3 sounds will be loaded from android/app/src/main/res/raw. You may specify a different directory using the path option for intrument():

ex: Load from the "Document" directory (using react-native-sound path macros for convenience)

import Sound from 'react-native-sound';
...
Soundfont.instrument('acoustic_piano` { path: Sound.DOCUMENT });

MP3 filenames must be in the following format for the player to recognize them:

<instrument>_<note>.mp3

For example: violin_C4.mp3

Some prepacked libraries can be found here.

To Do

• iOS support
• Implement an artifical sound envelope?
• Custom sound fonts (mp3 libs, sfz or midi.js?)