How to Replace Audio Track of a Video File

When editing videos for homemade movies you might feel the need to replace the audio track with one of better quality or different sound. Maybe you want to swap voices with music, or replace the original dialogues on a movie with different set of dialogues – a process called dubbing. Maybe the audio turned out to be distorted and you need to replace it. This short tutorial will show how to do just that.

Once again we will use the software Avidemux for our job. Open the video file which you want to edit from the File menu of Avidemux.

Click on the Audio menu at the top and then click on Select Track.

If your video file already has an audio track you will see the Track 1 checkbox Enabled. From the drop-down menu next to Track 1, select “Add audio track”.

This will open the file browser. Find and select the audio file which you wish to use it in place of the original audio track. We will assume you already have the audio track prepared or recorded and saved on the hard disk in an appropriate audio format.

After you have chosen the audio track, click the copy button adjacent to it and choose an audio codec to encode the audio track with. Select either AAC (lav) or AC3 (lav). If you choose MKV as the video container you should select AC3 for maximum compatibility with DVD and Blu-ray players and HD-TVs. For MP4 videos you have to choose AAC (lav) as other codecs are not supported.

Optionally choose the bitrate using the configure button. The default is 128kbps but you might want higher fidelity, so choose 192kbps or even 224kbps. Click OK to exit the window.

Now it’s possible that the audio track is out of sync with the video. If that happens check the Shift box on the left hand side of the program window and enter by how much time in milliseconds you want the audio to shift with respect to the video. A positive number will delay the audio with respect to the video, while a negative shift will cause the audio to play ahead of the video.

Once you have correctly aligned the audio with the video, hit the Save button. Encoding should take from a couple of seconds to a few minutes depending on how large the video file is.

If everything goes fine you will have replaced the audio of the video file.