Instance Method


This is called when you set the format on a bus.


- (BOOL)shouldChangeToFormat:(AVAudioFormat *)format forBus:(AUAudioUnitBus *)bus;



The proposed new format.


The bus on which the format will be changed.

Return Value

  • YES if the new format will be set on the bus.

  • NO if the new format will not be set on the bus.


The bus has already checked that the format meets its channel constraints. The audio unit can override this method to check the format before allowing it to be set on the bus.

The default implementation returns NO if the audio unit’s renderResourcesAllocated value is YES.

See Also

Audio Unit Implementations


The block which you must provide, via a getter, in order to implement rendering.

+ registerSubclass:asComponentDescription:name:version:

Registers an audio unit component implemented as an AUAudioUnit subclass.

- setRenderResourcesAllocated:

Sets the Boolean value of the renderResourcesAllocated property.