Stereo audio files to be convert to 8 bit mono in .net

Stereo audio files to be convert to 8 bit mono in .net

Hey Mr. Annarfoster,

There are two steps in audio conversion: 1. Decoding and 2. Encoding.

Logically, we will first need to decode the audio to PCM and then encode to required format.

Well, converting stereo to mono is very simple. We know that stereo has 2 samples-left and right. Discarding any one of them will give us mono audio format.

Here is the code you need:(We are discarding the right channel)

private byte[] StereoToMono(byte[] input)

{

    byte[] output = new byte[input.Length / 2]; //to discard input length

    int outputIndex = 0;

    for (int n = 0; n < input.Length; n+=4)

    {

        // copy in the first 16 bit sample

        output[outputIndex++] = input[n];

        output[outputIndex++] = input[n+1];

    }

    return output;

}

 

Method 2:

Alternatively, we can try mixing the two samples together:

(I have used Bitconverter function and every two bytes are converted to Int16)

private byte[] MixStereoToMono(byte[] input)

{

    byte[] output = new byte[input.Length / 2];

    int outputIndex = 0;

    for (int n = 0; n < input.Length; n+=4)

    {

        int leftChannel = BitConverter.ToInt16(input,n);

        int rightChannel = BitConverter.ToInt16(input,n+2);

        int mixed = (leftChannel + rightChannel) / 2;

        byte[] outSample = BitConverter.GetBytes((short)mixed);

        // copy in the first 16 bit sample

        output[outputIndex++] = outSample[0];

        output[outputIndex++] = outSample[1];

    }

    return output;

}

Let me know if this helps.