merging recorded audio with existing mp3 file android

Question

I am learning android development, and trying to make face filters with sound in background like snapchat or Facebook. But I am unable to record the audio playing in the filter with user sound while using headphones.

Please help! or some links which can be useful for me

Answer 1

import java.io.*;
public class TwoFiles
{
    public static void main(String args[]) throws IOException
    {
        FileInputStream fistream1 = new FileInputStream("C:\\Temp\\1.mp3");  // first source file
        FileInputStream fistream2 = new FileInputStream("C:\\Temp\\2.mp3");//second source file
        SequenceInputStream sistream = new SequenceInputStream(fistream1, fistream2);
        FileOutputStream fostream = new FileOutputStream("C:\\Temp\\final.mp3");//destinationfile

        int temp;

        while( ( temp = sistream.read() ) != -1)
        {
            // System.out.print( (char) temp ); // to print at DOS prompt
            fostream.write(temp);   // to write to file
        }
        fostream.close();
        sistream.close();
        fistream1.close();
        fistream2.close();
    }
}