ConstantSourceNode: offset property
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2021.
The read-only offset
property of the ConstantSourceNode
interface returns a AudioParam
object indicating the numeric a-rate value which is always returned
by the source when asked for the next sample.
Note:
While the AudioParam
named offset
is read-only, the
value
property within is not. So you can change the value of
offset
by setting the value of
ConstantSourceNode.offset.value
:
myConstantSourceNode.offset.value = newValue;
Value
An AudioParam
object indicating the a-rate value returned for every
sample by this node. The default value is 1.0.
To access the offset
parameter's current value, access the parameter's
value
property, as shown in the syntax box above.
Examples
This example shows how to set up a ConstantSourceNode
so its
offset
is used as the input to a pair of GainNode
s; this
snippet is derived from the complete example you can find in Controlling multiple parameters with ConstantSourceNode.
gainNode2 = context.createGain();
gainNode3 = context.createGain();
gainNode2.gain.value = gainNode3.gain.value = 0.5;
volumeSliderControl.value = gainNode2.gain.value;
constantSource = context.createConstantSource();
constantSource.connect(gainNode2.gain);
constantSource.connect(gainNode3.gain);
First, the gain nodes are created and configured, and a slider control's value is set
to match the gain on the two nodes. Then we create a new
ConstantSourceNode
and make it the source for the two gain nodes'
GainNode.gain
values. Each of those values is also an
AudioParam
.
Let's say we have an event handler (for click
events, in this case) which
needs to respond by altering the value of the two gain nodes. With the linkage above in
place, that can be done using this simple event handler:
function handleClickEvent(event) {
constantSource.offset.value = volumeSliderControl.value;
}
All this function has to do is fetch the current value of the slider control we're
using to control the paired nodes' gains, then store that value into the
ConstantSourceNode
's offset
parameter. That's done by changing
the contents of its AudioParam.value
property. The two gain nodes quickly
adopt the new volume level.
Specifications
Specification |
---|
Web Audio API # dom-constantsourcenode-offset |
Browser compatibility
BCD tables only load in the browser