CODEWITHSUNDEEP
core-audioavaudiosessionavmutablecompositionavaudioengineavaudioplayernode
Dallas Johnson
Dallas Johnson

Reputation: 1536

How to use AVAudioPlayerNode with AVMutableComposition

The AVAudioEngine and related AVAudioNode objects seem to be quite powerful for audio processing but it's difficult to see how to automate parameter changes with them. I'm sure there must be something more effective than manually using a Timer to change values, as a crude example.

AVMutableAudioMixInputParameters includes a method setVolumeRampFromStartVolume:toEndVolume:timeRange: but I cannot see how I could integrate that with AVAudioPlayerNode (connected with AVAudioEffectNodes) and use that method to fade the volume over time. Instead, I have only seen examples of AVMutableAudioMixInputParameters working with AVMutableCompositioninstances and none of them include AVAudioNode objects.

Can anyone post or link to some code samples that combine the use of AVAudioNodes with setVolumeRampFromStartVolume:toEndVolume:timeRange: or explain best practices for automating parameter changes on a node over time?

Many thanks

Upvotes: 2

Views: 512

Answers (1)

hotpaw2
hotpaw2

Reputation: 70693

The AVAudioEngine is a real-time engine, but AVMutableComposition seems to be a non-real-time object. Thus incompatible. An alternative is to build and insert your own fader real-time AUAudioUnit node..

Upvotes: 3

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