How to mix / overlay two mp3 audio file into one mp3 file (not concatenate)

Question

I want to merge two mp3 files into one mp3 file.for example if 1st file is 1min and 2nd file is 30 sec then the output should be one min. In that one min it should play both

Answer 1

To merge (overlap) two sound files, you can use This FFMPEG library.

Here is the Documentation

In their sample you can just enter the command you want. So lets talk about the command that we need.

-i [FISRST_FILE_PATH] -i [SECOND_FILE_PATH] -filter_complex amerge -ac 2 -c:a libmp3lame -q:a 4 [OUTPUT_FILE_PATH]

For first and second file paths, you will get the absolute path of the sound file. 1- If it is on storage then it is a sub folder for Environment.getExternalStorageDirectory().getAbsolutePath()

2- If it is assets so it should be a sub folder for file:///android_asset/

For the output path, Make sure to add the extension ex.

String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/File Name.mp3"