Happy editing!
This is the culprit in 80% of cases. If your video is in an but you are trying to add an MP3 audio track , Avidemux will often refuse. Why? The MP4 specification strongly prefers AAC audio. While some players accept MP3-in-MP4, Avidemux adheres strictly to standards. avidemux cannot use that file as audio track
ffmpeg -i video.mp4 -i audio.mp3 -c:v copy -c:a copy -map 0:v:0 -map 1:a:0 output.mp4 Use code with caution. 3. Update Avidemux Happy editing
The most common reasons Avidemux rejects an audio file include: ffmpeg -i video
Recommended step-by-step using ffmpeg (reliable)
If none of the above solutions work, try using a different audio file to see if the issue is specific to the file.
Older versions of Avidemux have known bugs with specific audio headers. Ensuring you are on the latest stable release often resolves codec compatibility issues.