A plugin for recording/exporting the output of Web Audio API nodes

Using akrennmair/libmp3lame-js for mp3 support causes conflict in licensing (see the license section below). I'm not sure if this can be merged back to the original or not. I'm also not sure which license override which. Use at your own risk; or if you happen to be a lawyer, please explain this to me? Thanks!

var rec = new Recorder(source [, config])

Creates a recorder instance.

• source - The node whose output you wish to capture
• config - (optional) A configuration object (see config section below)

• workerPath - Path to recorder.js worker script. Defaults to 'js/recorderjs/recorderWorker.js'. For the mp3 output format, you will need to use the 'recorderWorkerMP3.js'.
• bufferLen - The length of the buffer that the internal JavaScriptNode uses to capture the audio. Can be tweaked if experiencing performance issues. Defaults to 4096.
• callback - A default callback to be used with exportAudio.
• type - The type of the Blob generated by exportAudio. Defaults to 'audio/wav'.

rec.record()
rec.stop()

Pretty self-explanatory... record will begin capturing audio and stop will cease capturing audio. Subsequent calls to record will add to the current recording.

rec.clear()

This will clear the recording.

rec.exportAudio([callback][, type])

This will generate a Blob object containing the recording in WAV format. The callback will be called with the Blob as its sole argument. If a callback is not specified, the default callback (as defined in the config) will be used. If no default has been set, an error will be thrown.

In addition, you may specify the type of Blob to be returned (defaults to 'audio/wav').

rec.getBuffer([callback])

This will pass the recorded stereo buffer (as an array of two Float32Arrays, for the separate left and right channels) to the callback. It can be played back by creating a new source buffer and setting these buffers as the separate channel data:

function getBufferCallback( buffers ) {
	var newSource = audioContext.createBufferSource();
	var newBuffer = audioContext.createBuffer( 2, buffers[0].length, audioContext.sampleRate );
	newBuffer.getChannelData(0).set(buffers[0]);
	newBuffer.getChannelData(1).set(buffers[1]);
	newSource.buffer = newBuffer;

	newSource.connect( audioContext.destination );
	newSource.start(0);
}

This sample code will play back the stereo buffer.

rec.configure(config)

This will set the configuration for Recorder by passing in a config object.

Recorder.forceDownload(blob[, filename])

This method will force a download using the new anchor link download attribute. Filename defaults to 'output.wav'.

Original mattdiamond/Recorderjs is licensed under MIT. akrennmair/libmp3lame-js is licensed under the same license as LAME which is LGPL.

I'm not sure how this will all works since I don't have a law degree. I wish it's just all WTFPL2.