Struct web_audio_api::buffer::AudioBuffer

pub struct AudioBuffer { /* private fields */ }

Memory-resident audio asset, basically a matrix of channels * samples

An AudioBuffer has copy-on-write semantics, so it is cheap to clone.

• MDN documentation: https://developer.mozilla.org/en-US/docs/Web/API/AudioBuffer
• specification: https://webaudio.github.io/web-audio-api/#AudioBuffer
• see also: BaseAudioContext::create_buffer

Usage

use std::f32::consts::PI;
use web_audio_api::context::{AudioContext, BaseAudioContext};
use web_audio_api::node::{AudioNode, AudioScheduledSourceNode};

let context = AudioContext::new(None);

let length = context.sample_rate() as usize;
let sample_rate = context.sample_rate_raw();
let mut buffer = context.create_buffer(1, length, sample_rate);

// fill buffer with a sine wave
let mut sine = vec![];

for i in 0..length {
    let phase = i as f32 / length as f32 * 2. * PI * 200.;
    sine.push(phase.sin());
}

buffer.copy_to_channel(&sine, 0);

// play the buffer in a loop
let src = context.create_buffer_source();
src.set_buffer(buffer.clone());
src.set_loop(true);
src.connect(&context.destination());
src.start();

Example

• cargo run --release --example audio_buffer

Implementations

impl AudioBuffer

pub fn new(options: AudioBufferOptions) -> Self

Allocate a silent audiobuffer with AudioBufferOptions

Panics

This function will panic if:

• the given sample rate is zero
• the given number of channels is outside the [1, 32] range, 32 being defined by the MAX_CHANNELS constant.

pub fn from(samples: Vec<Vec<f32>>, sample_rate: SampleRate) -> Self

Convert raw samples to an AudioBuffer

The outer Vec determine the channels. The inner Vecs should have the same length.

Panics

This function will panic if:

• the given sample rate is zero
• the given number of channels defined by samples.len()is outside the [1, 32] range, 32 being defined by the MAX_CHANNELS constant.
• any of its items have different lengths

pub fn number_of_channels(&self) -> usize

Number of channels in this AudioBuffer

pub fn length(&self) -> usize

Number of samples per channel in this AudioBuffer

pub fn sample_rate(&self) -> f32

Sample rate of this AudioBuffer in Hertz

pub fn sample_rate_raw(&self) -> SampleRate

The raw sample rate of the AudioBuffer (which has more precision than the float sample_rate() value).

pub fn duration(&self) -> f64

Duration in seconds of the AudioBuffer

pub fn copy_from_channel(&self, destination: &mut [f32], channel_number: usize)

Copy data from a given channel to the given Vec

Panics

This function will panic if channel_number is greater or equal than AudioBuffer::number_of_channels()

pub fn copy_from_channel_with_offset(
    &self,
    destination: &mut [f32],
    channel_number: usize,
    offset: usize
)

Copy data from a given channel to the given Vec starting at offset

Panics

This function will panic if:

• the given channel number is greater than or equal to the given number of channels.

pub fn copy_to_channel(&mut self, source: &[f32], channel_number: usize)

Copy data from a given source to the given channel.

Panics

This function will panic if:

• the given channel number is greater than or equal to the given number of channels.

pub fn copy_to_channel_with_offset(
    &mut self,
    source: &[f32],
    channel_number: usize,
    offset: usize
)

Copy data from a given source to the given channel starting at offset.

Panics

This function will panic if:

• the given channel number is greater than or equal to the given number of channels.

pub fn get_channel_data(&self, channel_number: usize) -> &[f32]

Return a read-only copy of the underlying data of the channel

Panics

This function will panic if:

• the given channel number is greater than or equal to the given number of channels.

Trait Implementations

impl Clone for AudioBuffer

fn clone(&self) -> AudioBuffer

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AudioBuffer

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

Formats the value using the given formatter.