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
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
AudioContext() constructor | Chrome
Full support
55
| Edge Full support ≤18 | Firefox Full support 25 | IE No support No | Opera Full support 42 | Safari
Full support
Yes
| WebView Android Full support 55 | Chrome Android
Full support
55
| Firefox Android Full support 26 | Opera Android Full support 42 | Safari iOS
Full support
Yes
| Samsung Internet Android
Full support
6.0
|
latencyHint option | Chrome Full support 60 | Edge Full support 79 | Firefox No support No | IE No support No | Opera Full support 47 | Safari ? | WebView Android Full support 60 | Chrome Android Full support 60 | Firefox Android No support No | Opera Android Full support 44 | Safari iOS ? | Samsung Internet Android Full support 8.0 |
sampleRate option | Chrome Full support 74 | Edge Full support 79 | Firefox No support No | IE No support No | Opera No support No | Safari Full support Yes | WebView Android Full support 74 | Chrome Android Full support 74 | Firefox Android ? | Opera Android ? | Safari iOS Full support Yes | Samsung Internet Android Full support 11.0 |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
- Experimental. Expect behavior to change in the future.
- Experimental. Expect behavior to change in the future.
- See implementation notes.
- See implementation notes.
- Requires a vendor prefix or different name for use.
- Requires a vendor prefix or different name for use.
See also
new OfflineAudioContext()
constructor