Struct AudioContext

pub struct AudioContext { /* private fields */ }

This interface represents an audio graph whose AudioDestinationNode is routed to a real-time output device that produces a signal directed at the user.

Implementations

impl AudioContext

pub fn new(options: AudioContextOptions) -> Self

Creates and returns a new AudioContext object.

This will play live audio on the default output device.

use web_audio_api::context::{AudioContext, AudioContextOptions};

// Request a sample rate of 44.1 kHz and default latency (buffer size 128, if available)
let opts = AudioContextOptions {
    sample_rate: Some(44100.),
    ..AudioContextOptions::default()
};

// Setup the audio context that will emit to your speakers
let context = AudioContext::new(opts);

// Alternatively, use the default constructor to get the best settings for your hardware
// let context = AudioContext::default();

Panics

The AudioContext constructor will panic when an invalid sinkId is provided in the AudioContextOptions. In a future version, a try_new constructor will be introduced that never panics.

pub fn base_latency(&self) -> f64

This represents the number of seconds of processing latency incurred by the AudioContext passing the audio from the AudioDestinationNode to the audio subsystem.

pub fn output_latency(&self) -> f64

The estimation in seconds of audio output latency, i.e., the interval between the time the UA requests the host system to play a buffer and the time at which the first sample in the buffer is actually processed by the audio output device.

pub fn sink_id(&self) -> String

Identifier or the information of the current audio output device.

The initial value is "", which means the default audio output device.

pub fn render_capacity(&self) -> AudioRenderCapacity

Returns an AudioRenderCapacity instance associated with an AudioContext.

pub fn set_sink_id_sync(&self, sink_id: String) -> Result<(), Box<dyn Error>>

Update the current audio output device.

The provided sink_id string must match a device name enumerate_devices_sync.

Supplying "none" for the sink_id will process the audio graph without playing through an audio output device.

This function operates synchronously and might block the current thread. An async version is currently not implemented.

pub fn set_onsinkchange<F: FnMut(Event) + Send + 'static>(&self, callback: F)

Register callback to run when the audio sink has changed

Only a single event handler is active at any time. Calling this method multiple times will override the previous event handler.

pub fn clear_onsinkchange(&self)

Unset the callback to run when the audio sink has changed

pub async fn suspend(&self)

Suspends the progression of time in the audio context.

This will temporarily halt audio hardware access and reducing CPU/battery usage in the process.

Panics

Will panic if:

• The audio device is not available
• For a BackendSpecificError

pub async fn resume(&self)

Resumes the progression of time in an audio context that has previously been suspended/paused.

Panics

Will panic if:

• The audio device is not available
• For a BackendSpecificError

pub async fn close(&self)

Closes the AudioContext, releasing the system resources being used.

This will not automatically release all AudioContext-created objects, but will suspend the progression of the currentTime, and stop processing audio data.

Panics

Will panic when this function is called multiple times

pub fn suspend_sync(&self)

Suspends the progression of time in the audio context.

This will temporarily halt audio hardware access and reducing CPU/battery usage in the process.

This function operates synchronously and blocks the current thread until the audio thread has stopped processing.

Panics

Will panic if:

• The audio device is not available
• For a BackendSpecificError

pub fn resume_sync(&self)

Resumes the progression of time in an audio context that has previously been suspended/paused.

This function operates synchronously and blocks the current thread until the audio thread has started processing again.

Panics

Will panic if:

• The audio device is not available
• For a BackendSpecificError

pub fn close_sync(&self)

Closes the AudioContext, releasing the system resources being used.

This will not automatically release all AudioContext-created objects, but will suspend the progression of the currentTime, and stop processing audio data.

This function operates synchronously and blocks the current thread until the audio thread has stopped processing.

Panics

Will panic when this function is called multiple times

pub fn create_media_stream_source( &self, media: &MediaStream, ) -> MediaStreamAudioSourceNode

Creates a MediaStreamAudioSourceNode from a MediaStream

pub fn create_media_stream_destination(&self) -> MediaStreamAudioDestinationNode

Creates a MediaStreamAudioDestinationNode

pub fn create_media_stream_track_source( &self, media: &MediaStreamTrack, ) -> MediaStreamTrackAudioSourceNode

Creates a MediaStreamTrackAudioSourceNode from a MediaStreamTrack

pub fn create_media_element_source( &self, media_element: &mut MediaElement, ) -> MediaElementAudioSourceNode

Creates a MediaElementAudioSourceNode from a MediaElement

Trait Implementations

impl BaseAudioContext for AudioContext

fn decode_audio_data_sync<R: Read + Send + Sync + 'static>( &self, input: R, ) -> Result<AudioBuffer, Box<dyn Error + Send + Sync>>

Decode an AudioBuffer from a given input stream.

fn decode_audio_data<R: Read + Send + Sync + 'static>( &self, input: R, ) -> impl Future<Output = Result<AudioBuffer, Box<dyn Error + Send + Sync>>> + Send + 'static

Decode an AudioBuffer from a given input stream.

fn create_buffer( &self, number_of_channels: usize, length: usize, sample_rate: f32, ) -> AudioBuffer

Create an new “in-memory” AudioBuffer with the given number of channels, length (i.e. number of samples per channel) and sample rate.

fn create_analyser(&self) -> AnalyserNode

Creates a AnalyserNode

fn create_biquad_filter(&self) -> BiquadFilterNode

Creates an BiquadFilterNode which implements a second order filter

fn create_buffer_source(&self) -> AudioBufferSourceNode

Creates an AudioBufferSourceNode

fn create_constant_source(&self) -> ConstantSourceNode

Creates an ConstantSourceNode, a source representing a constant value

fn create_convolver(&self) -> ConvolverNode

Creates an ConvolverNode, a processing node which applies linear convolution

fn create_channel_merger(&self, number_of_inputs: usize) -> ChannelMergerNode

Creates a ChannelMergerNode

fn create_channel_splitter( &self, number_of_outputs: usize, ) -> ChannelSplitterNode

Creates a ChannelSplitterNode

fn create_delay(&self, max_delay_time: f64) -> DelayNode

Creates a DelayNode, delaying the audio signal

fn create_dynamics_compressor(&self) -> DynamicsCompressorNode

Creates a DynamicsCompressorNode, compressing the audio signal

fn create_gain(&self) -> GainNode

Creates an GainNode, to control audio volume

fn create_iir_filter( &self, feedforward: Vec<f64>, feedback: Vec<f64>, ) -> IIRFilterNode

Creates an IirFilterNode

fn create_oscillator(&self) -> OscillatorNode

Creates an OscillatorNode, a source representing a periodic waveform.

fn create_panner(&self) -> PannerNode

Creates a PannerNode

fn create_periodic_wave(&self, options: PeriodicWaveOptions) -> PeriodicWave

Creates a periodic wave

fn create_script_processor( &self, buffer_size: usize, number_of_input_channels: usize, number_of_output_channels: usize, ) -> ScriptProcessorNode

Creates an ScriptProcessorNode for custom audio processing (deprecated);

fn create_stereo_panner(&self) -> StereoPannerNode

Creates an StereoPannerNode to pan a stereo output

fn create_wave_shaper(&self) -> WaveShaperNode

Creates a WaveShaperNode

fn destination(&self) -> AudioDestinationNode

Returns an AudioDestinationNode representing the final destination of all audio in the context. It can be thought of as the audio-rendering device.

fn listener(&self) -> AudioListener

Returns the AudioListener which is used for 3D spatialization

fn sample_rate(&self) -> f32

The sample rate (in sample-frames per second) at which the AudioContext handles audio.

fn state(&self) -> AudioContextState

Returns state of current context

fn current_time(&self) -> f64

This is the time in seconds of the sample frame immediately following the last sample-frame in the block of audio most recently processed by the context’s rendering graph.

fn create_audio_param( &self, opts: AudioParamDescriptor, dest: &AudioContextRegistration, ) -> (AudioParam, AudioParamId)

Create an AudioParam.

fn set_onstatechange<F: FnMut(Event) + Send + 'static>(&self, callback: F)

Register callback to run when the state of the AudioContext has changed

fn clear_onstatechange(&self)

Unset the callback to run when the state of the AudioContext has changed

impl Debug for AudioContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for AudioContext

fn default() -> Self

Returns the “default value” for a type.

impl Drop for AudioContext

fn drop(&mut self)

Executes the destructor for this type.