How to adjust microphone sensitivity while recording audio in android

Question

I\'m working on a voice recording app. In it, I have a Seekbar to change the input voice gain. I couldn\'t find any way to adjust the input voice gain.

I am using th

Answer 1

This is working implementation based on ByteBuffer for 16bit audio. It's important to clamp the increased value from both sides since short is signed. It's also important to set the native byte order to ByteBuffer since audioRecord.read() returns native endian bytes.

You may also want to perform audioRecord.read() and following code in a loop, calling data.clear() after each iteration.

    double gain = 2.0;

    ByteBuffer data = ByteBuffer.allocateDirect(SAMPLES_PER_FRAME).order(ByteOrder.nativeOrder());

    int audioInputLengthBytes = audioRecord.read(data, SAMPLES_PER_FRAME);
    ShortBuffer shortBuffer = data.asShortBuffer();
    for (int i = 0; i < audioInputLengthBytes / 2; i++) { // /2 because we need the length in shorts
        short s = shortBuffer.get(i);
        int increased = (int) (s * gain);
        s = (short) Math.min(Math.max(increased, Short.MIN_VALUE), Short.MAX_VALUE);
        shortBuffer.put(i, s);
    }