The AudioContext()
constructor
creates a new AudioContext
object which represents an audio-processing
graph, built from audio modules linked together, each represented by an
AudioNode
.
Syntax
var audioCtx = new AudioContext();
var audioCtx = new AudioContext(options);
Parameters
options
Optional- An object based on the
AudioContextOptions
dictionary that contains zero or more optional properties to configure the new context. Available properties are as follows:latencyHint
Optional- The type of playback that the context will be used for, as a value from the
AudioContextLatencyCategory
enum or a double-precision floating-point value indicating the preferred maximum latency of the context in seconds. The user agent may or may not choose to meet this request; check the value ofAudioContext.baseLatency
to determine the true latency after creating the context. sampleRate
Optional- The
sampleRate
to be used by theAudioContext
, specified in samples per second. The value may be any value supported byAudioBuffer
. If not specified, the preferred sample rate for the context's output device is used by default.
Return value
The newly constructed AudioContext
instance.
Exceptions
NotSupportedError
- The specified
sampleRate
isn't supported by the context.
Usage notes
The specification doesn't go into a lot of detail about things like how many audio contexts a user agent should support, or minimum or maximum latency requirements (if any), so these details can vary from browser to browser. Be sure to check the values if they matter to you.
In particular, the specification doesn't indicate a maximum or minimum number of audio contexts that must be able to be open at the same time, so this is left up to the browser implementations to decide.
Google Chrome
Per-tab audio context limitation in Chrome
Prior to version 66 Google Chrome only supported up to six audio contexts per tab at a time.
Non-standard exceptions in Chrome
If the value of the latencyHint
property isn't valid, Chrome throws a TypeError
exception with the message
"The provided value '...' is not a valid enum value of type
AudioContextLatencyCategory".
Example
This example creates a new AudioContext
for interactive audio
(optimizing for latency) and a sample rate of 44.1kHz.
var AudioContext = window.AudioContext || window.webkitAudioContext;
var audioCtx = new AudioContext({
latencyHint: 'interactive',
sampleRate: 44100,
});
Specifications
Specification | Status | Comment |
---|---|---|
Web Audio API The definition of 'AudioContext()' in that specification. |
Working Draft | Initial definition. |
Browser compatibility
BCD tables only load in the browser
See also
new OfflineAudioContext()
constructor