command = new String[]{
                    "-ss", getConvertedValue(getSyncCalibration()),
                    "-i", mVoiceFileTemp.getAbsolutePath(),
                    "-i", mBeatFileTemp.getAbsolutePath(),
                    "-filter_complex",
                    "[0:a]volume=1[a1];[1:a]volume=1[a2];[a1][a2]amerge=inputs=2,pan=stereo|c0<c0+c2|c1<c1+c3[aout]",
                    "-map",
                    "[aout]",
                    mRapFileTemp.getAbsolutePath()};