Trait AudioWorkletProcessor

pub trait AudioWorkletProcessor {
    type ProcessorOptions: Send;

    // Required methods
    fn constructor(opts: Self::ProcessorOptions) -> Self
       where Self: Sized;
    fn process<'a, 'b>(
        &mut self,
        inputs: &'b [&'a [&'a [f32]]],
        outputs: &'b mut [&'a mut [&'a mut [f32]]],
        params: AudioParamValues<'b>,
        scope: &'b AudioWorkletGlobalScope,
    ) -> bool;

    // Provided methods
    fn parameter_descriptors() -> Vec<AudioParamDescriptor>
       where Self: Sized { ... }
    fn onmessage(&mut self, _msg: &mut dyn Any) { ... }
}

Audio processing code that runs on the audio rendering thread.

Required Associated Types

type ProcessorOptions: Send

Constructor options for the audio processor

This holds any user-defined data that may be used to initialize custom properties in an AudioWorkletProcessor instance that is associated with the AudioWorkletNode.

Required Methods

fn constructor(opts: Self::ProcessorOptions) -> Self

where Self: Sized,

Constructor of the AudioWorkletProcessor instance (to be executed in the render thread)

fn process<'a, 'b>( &mut self, inputs: &'b [&'a [&'a [f32]]], outputs: &'b mut [&'a mut [&'a mut [f32]]], params: AudioParamValues<'b>, scope: &'b AudioWorkletGlobalScope, ) -> bool

Audio processing function

Arguments

• inputs: readonly array of input buffers
• outputs: array of output buffers
• params: available AudioParam values for this processor
• scope: AudioWorkletGlobalScope object with current frame, timestamp, sample rate

Return value

The return value (bool) of this callback controls the lifetime of the processor.

• return false when the node only transforms their inputs, and as such can be removed when the inputs are disconnected (e.g. GainNode)
• return true for some time when the node still outputs after the inputs are disconnected (e.g. DelayNode)
• return true as long as this node is a source of output (e.g. OscillatorNode)

Provided Methods

fn parameter_descriptors() -> Vec<AudioParamDescriptor>

where Self: Sized,

List of AudioParams for this audio processor

A default implementation is provided that supplies no parameters.

fn onmessage(&mut self, _msg: &mut dyn Any)

Handle incoming messages from the linked AudioNode

By overriding this method you can add a handler for messages sent from the control thread via the AudioWorkletNode MessagePort.

Receivers are supposed to consume the content of msg. The content of msg might also be replaced by cruft that needs to be deallocated outside of the render thread afterwards, e.g. when replacing an internal buffer.

This method is just a shim of the full MessagePort onmessage functionality of the AudioWorkletProcessor.

Implementors