Merge two Audio with volume using ffmpeg

 Library : implementation 'com.arthenica:mobile-ffmpeg-full:4.2.2.LTS'

List<String> cmdList = new ArrayList<>();

cmdList.clear();

cmdList.add("-y");

cmdList.add("-i");

cmdList.add(orignalAudio);

cmdList.add("-stream_loop");

cmdList.add("-1");

cmdList.add("-i");

cmdList.add(backgroundAudio);

cmdList.add("-filter_complex");

cmdList.add("[0]volume=1:precision=fixed[a];" + "[1]volume=0.1:precision=fixed[b];" +

        "[a][b]amix=inputs=2:duration=shortest"); 

// Note : you can set volume of both audio by change value of volume parameter. volume value is 0.0 to 1.

cmdList.add("-ac");

cmdList.add("2");

cmdList.add("-c:a");

cmdList.add("libmp3lame");

cmdList.add("-q:a");

cmdList.add("4");

cmdList.add(outputPath);

int returnCode = com.arthenica.mobileffmpeg.FFmpeg.execute(cmdList.toArray(new String[cmdList.size()]));

if (returnCode == RETURN_CODE_SUCCESS) {

   //  Completed with success
} else if (returnCode == RETURN_CODE_CANCEL) {

} else {

}