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androidc++audiooboe

How to amplify Audio Data in Oboe onAudioReady Method?

I want to amplify the audioData that is recorded by microphone using Oboe Library. I created AudioEngine.cpp like this: https://github.com/google/oboe/blob/master/samples/LiveEffect/src/main/cpp/LiveEffectEngine.cpp Here's is the class that has audioData:

DataCallbackResult
AudioEngine::onAudioReady(AudioStream *oboeStream, void *audioData, int32_t numFrames) {

    /* some code */


 // add your audio processing here

    return DataCallbackResult::Continue;
}
Solution

  • In the LiveEffect sample both the recording and playback streams are AudioFormat::I16 i.e. 16 bit integers. On this line you're casting to float: 

    auto *outputData = static_cast<float *>(audioData);

    This is going to cause the distortion you hear so instead just cast to int16_t and multiply by a constant amplitude.

    Make sure to check that the scaled up sample value isn't above INT16_MAX otherwise you'll get wraparound and distortion.