You can access PCM data from the microphone on a PC or Android phone via the AudioRecorder (code) interface. To create an instance of that interface use:
AudioRecorder recorder = Gdx.audio.newAudioRecorder(22050, true);
This will create an AudioRecorder with a sampling rate of 22.05khz, in mono mode. If the recorder couldn’t be created, a GdxRuntimeException will be thrown.
Samples can be read as 16-bit signed PCM:
short[] shortPCM = new short[1024]; // 1024 samples
recorder.readSamples(shortPCM, 0, shortPCM.length);
Stereo samples are interleaved as usual (first sample -> left channel, second sample -> right channel).
An AudioRecorder is a native resource and needs to be disposed of if no longer in use:
recorder.dispose();
Audio recording is not supported in the JavaScript/WebGL backend.