How to save the audio with changed pitch and speed iOS?

问题

I'm able to change the pitch and speed of my audio but I'm getting problem in saving the audio with changed pitch and speed

//this is method which set the pitch  
[self.audioEngine connect:audioPlayerNode
                       to:timePitchEffect
                   format:nil];
[self.audioEngine connect:timePitchEffect
                       to:self.audioEngine.outputNode
                   format:nil];

[audioPlayerNode scheduleFile:self.audioFile
                       atTime:nil
            completionHandler:nil];
[self.audioEngine startAndReturnError:&audioEngineError];
NSLog(@"%@",self.audioFile.url);
if (audioEngineError) {
    NSLog(@"%@",@"whats this!!!");
}

// call the method on button tap

[self playAudioWithEffect:EAudioEffectPitch effectValue:@-500.0];

I'm changing the pitch using this function but how to save it with changed pitch .... please help...

来源：https://stackoverflow.com/questions/39052576/how-to-save-the-audio-with-changed-pitch-and-speed-ios