OfflineAudioContext without a rendered buffer

[chrisguttandin]

Describe the feature It would be nice if the OfflineAudioContext could be configured to not allocate any memory for the rendered AudioBuffer in case it is not needed.

Is there a prototype? No.

Describe the feature in more detail Sometimes an OfflineAudioContext is only used to compute a side effect and not really for rendering a buffer.

Let's imagine you have an AudioWorkletNode which just scans the signal for its maximum value. Its usage might look like this:

const offlineAudioContext = new OfflineAudioContext({ length: 44100, sampleRate: 44100 });
const audioBufferSourceNode = new AudioBufferSourceNode(
    offlineAudioContext,
    { buffer: aBufferFromSomewhere }
);
// This could be an AudioWorkletNode which scans the signal for its maximum value. 
const maximumValueNode = new MaximumValueNode(offlineAudioContext);

audioBufferSourceNode.start(0);
audioBufferSourceNode
    .connect(maximumValueNode)
    .connect(offlineAudioContext.destination);

offlineAudioContext
    .startRendering()
    .then(() => {
        // Now that the rendering is done ask the MaximumValueNode for the maximum value.
        console.log(maximumValueNode.maximumValue);
    });

In the example above the OfflineAudioContext is only used to drive the processing of the data but the rendered buffer is not really needed. I think it would be beneficial if the buffer doesn't need to be created in any case.

[guest271314]

In this case an AudioBuffer does not necessarily need to be created at all https://github.com/guest271314/audioInputToWav/blob/master/index.html#L345. The equivalent of an AudioBuffer can be an Array where Array.prototype.find() and Math.max() can be utilized to get the maximum value of a float.

[padenot]

Virtual F2F:

• There is going to be a way to have progressive rendering of OfflineAudioContext (talked about in #66 but also other issues), at which point the allocation will not be made (and will have to be made by the authors themselves, if needed). This problem then disappears.