How to amplify Audio Data in Oboe onAudioReady Method?

Question

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;
}

I tried 0.2f instead of 2, still it's distorting heavily. – Jazib Khan Mar 27 '19 at 19:10 — Jazib Khan, Mar 27 '19 at 19:10

score 1 · Accepted Answer · answered Apr 02 '19 at 10:57

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.

How to amplify Audio Data in Oboe onAudioReady Method?

1 Answers1