InstallTapOnBus - for output signal

Question

As in topic subject, I want to analyze buffer of the output signal. I've used this function ( InstallTapOnBus ) for microphone signal, but i does not work for output. Anyone know how do that?

    let bus = 0 
    let node = engine.outputNode
    node.installTap(onBus: bus, bufferSize: AVAudioFrameCount(BUFFER_SIZE), format: node.outputFormat(forBus: bus), block: { (buffer : AVAudioPCMBuffer ,time : AVAudioTime) in

        ...

    })
    try! engine.start()
}

It provides me an error : "required condition is false: _isInput"

score 2 · Answer 1 · answered May 05 '17 at 21:32

2

Have you tried tapping the mixer instead of the microphone directly?

answered May 05 '17 at 21:32

Chris

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score 2 · Answer 2 · answered Jul 01 '19 at 18:30

2

Try mainMixerNode instead of outputNode.

This worked for me (iOS 12):

let outputNode = self.audioEngine.mainMixerNode let format = self.audioEngine.mainMixerNode.outputFormat(forBus: 0)

Then installTap on mainMixerNode like you did.

answered Jul 01 '19 at 18:30

Nick

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InstallTapOnBus - for output signal

2 Answers2