When using a video as a menu background, any separate background music will be ignored—even if the video itself has no audio track. To embed (multiplex) music directly into a video, you can use the free tool MKVToolNix (https://mkvtoolnix.download/), available for both Windows and Mac. It also supports video splitting.

 

Steps:

1. Download and install MKVToolNix from https://mkvtoolnix.download/.

2. Load your video file into the program.

 

 

3. Load your music file, choosing “Add as new source files to the current multiplex settings.”

 

4. In the track list:

• Keep the video track from the first file.
• Keep the audio track from the second file.
• Deselect all other tracks from the first file.

 

5.Keep the audio and video duration the same.

• Go to the “Output” tab.
• Check "Stop after video track end".

6. Set the output file path.

7. Click “Start multiplexing.”

 

Your new video will now include the background music.