Audio record AUX-to-AUX is not working in Android

[raghugunda]

I'm Developing new application which records audio from digital stethoscope to mobile app. there are 2 ways to connect stethoscope to mobile.

1.AUX to AUX 2.Aux to USB

mediaRecorder = new MediaRecorder();

    mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
    mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
    mediaRecorder.setAudioEncodingBitRate(16*44100);
    mediaRecorder.setAudioSamplingRate(44100);

    mediaRecorder.setMaxDuration((int) TimeUnit.SECONDS.toMillis(30L));
    mediaRecorder.setOutputFile(AudioSavePathInDevice);

        mediaRecorder.prepare();
        mediaRecorder.start();```

But AUX to Aux not working in some device.AUX to USB recorded voice having poor quality.

Note : How to disable builtin mic when headphone is connected.