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iosavfoundationavaudiosession
Pablo Martinez
Pablo Martinez

Reputation: 1639

Add gain to AVAudiosession iOS

I'm trying to add more gain to the AVAudioSession.

I'm using AVAssetWriter to record a video with audio, but I would like to add more gain to the audio.

I saw there is a method in AVAudioSession to set the inputGain, but it must be between 0 and 1.

[[AVAudioSession sharedInstance] setInputGain:2.0 error:nil];

Is there any way to add more gain even if I have to lose quality?

Thanks

Upvotes: 2

Views: 520

Answers (2)

Pablo Martinez
Pablo Martinez

Reputation: 1639

Finally I've got this using Audiounit framework

Upvotes: 0

Gordon Childs
Gordon Childs

Reputation: 36084

You could increase the gain yourself by modifying the incoming audio LPCM CMSampleBuffers before you pass them on to the AVAssetWriter. NB: AVCaptureSession may not take kindly to you modifying its buffers, so you may need to duplicate them before modifying.

Alternatively, you may get more gain using AVAudioSessionModeMeasurement:

NSError *error;
if (![[AVAudioSession sharedInstance] setMode:AVAudioSessionModeMeasurement error:&error]) {
    // Error
}

which is

Appropriate for applications that wish to minimize the effect of system-supplied signal processing for input and/or output audio signals.

Upvotes: 1

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