Is it possible to create something like AudioStreamRandomizer within GDScript?

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Godot Version

v4.6.stable.official [89cea1439]

How best to replicate AudioStreamRandomizer in GDScript?

Right now, I have code like this. It’s similar to an AudioStreamRandomizer, but it provides a single stream, with controls over the playback. For example pitch and a db offset.

extends AudioStream
class_name SoundEffect

@export var stream : AudioStream
@export var pitch : float = 1.0
@export var db_offset : float = 0.0

func _instantiate_playback() -> AudioStreamPlayback:
	var playback = stream.instantiate_playback()
	playback.start()
	
	return playback

Setup

As far as I can tell, there are a few moving pieces:

  1. The audio stream, which allows creating a playback. For now I can rely on instantiate_playback within my stream.
  2. The AudioStreamPlayback itself.

I believe AudioStreamRandomizer resource uses a playback called AudioStreamPlaybackRandomizer which isn’t exposed to GDScript. I think this is where the volume and pitch is set.

In any case, I think the control is handled here:

int AudioStreamPlaybackRandomizer::mix(AudioFrame *p_buffer, float p_rate_scale, int p_frames) {
	if (playing.is_valid()) {
		int mixed_samples = playing->mix(p_buffer, p_rate_scale * pitch_scale, p_frames);
		for (int samp = 0; samp < mixed_samples; samp++) {
			p_buffer[samp] *= volume_scale;
		}
		return mixed_samples;
	} else {
		for (int i = 0; i < p_frames; i++) {
			p_buffer[i] = AudioFrame(0, 0);
		}
		return p_frames;
	}
}

But there is this in the docs:

Override this method to customize how the audio stream is mixed. This method is called even if the playback is not active.

Note: It is not useful to override this method in GDScript or C#. Only GDExtension can take advantage of it.

So it seems like I might be blocked…? Any ideas?