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I’m struggling since days trying to obtain a raw audio stream from the microphone. I am trying different ways: the low-level JNI way with Oboe Library (either AAudio and OpenSL ES implementations) and the Android’s AudioRecord Java classes.

The problem I am facing is that I am not able to retrieve amplitudes near -/+1.0 while being sure of saturating the microphone input with a calibrated pure tone with such a high amplitude. I think that the problem is that I am not able to effectively disable the signal preprocessing from AndroidOS (Automatic Gain Control or Noise Cancelling).

AutomaticGainControl.create(id).setEnabled(false)

(not working!)

Also, it seems that it is not possible also to disable any additional microphone rather than the one "selected" (done that as selecting the setPreferredDevice on AudioRecord instance). Used as audio source: unprocessed, mic, voice_recognition.

Is there anyway doing this or am I missing something?

Thank you

SirSeymour
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1 Answers1

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Which audio source are you using for your recording? VOICE_RECOGNITION or UNPROCESSED are mandated to not have any pre-processing enabled by default (i.e. see https://source.android.com/compatibility/10/android-10-cdd#5_11_capture_for_unprocessed) and therefore would allow you to check your signal path.

Jean-Michel Trivi
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