How to Replace or Add an Audio Track in Avidemux (External Audio)
To replace or add an audio track in Avidemux, load your video, open Audio → Select Track, and choose an external audio file to add it as a new track. The original video picture is untouched — you are simply pairing a different audio stream with it. This is the fastest way to dub a video, swap a commentary track, or fix a corrupted audio stream, and it works with or without re-encoding the video.
Step-by-step: replace the audio with an external file
- Open the video in Avidemux.
- Open Audio → Select Track. This opens the audio track manager.
- Activate one of the track slots (tracks are numbered; exact layout depends on your build) and choose the external audio file from your disk as its source.
- Disable the original audio track if you want a full replacement, or leave it enabled to keep both tracks.
- Set Audio Output to an encoder such as
AAC (lav)(orCopyif the external track’s codec already matches your output container), choose your Output Format, and save.
External audio format compatibility table
Avidemux accepts a wide range of external audio codecs, but only as elementary or supported streams — not inside every container. Get this right before you start, or the track simply won’t load.
| External file type | Accepted? | Notes |
|---|---|---|
| WAV (16-bit or 24-bit PCM) | Yes | The safest choice — always works. |
| MP3 | Yes | Reliable; good fallback after WAV. |
| AC3 | Yes | Common for film/TV rips. |
| E-AC3 (Dolby Digital Plus) | Yes | Accepted, but check your target players can decode it. |
| DTS | Yes | Accepted for import; confirm the output container supports it. |
| AAC in ADTS stream form | Yes | Works as an external stream. |
| Audio-only MP4 / M4A container | No — common trap | Avidemux does not accept an audio track wrapped in an MP4/M4A container as an external source. Convert it to WAV or MP3 first with a tool like FFmpeg (ffmpeg -i in.m4a out.wav) and load that instead. |
The M4A trap: this is the single most common reason the “add external audio” step silently fails. The file plays fine everywhere else, but Avidemux’s external-audio loader rejects MP4-wrapped audio. Converting to WAV first takes seconds and always works.
Multi-track tips (Avidemux 2.8.x)
Avidemux 2.8.x supports up to 32 audio tracks per project, so you can ship a video with several audio options — original language, dub, commentary — in one file:
- Keep the original: don’t disable track 1. Add the external file as track 2 so viewers can switch languages in their player.
- Full replacement: disable the original track and enable only the external one before saving.
- Codec compatibility per container: if you save as MP4, prefer AAC tracks; MKV accepts the full range above. An unsupported combination can produce a file some players report as silent.
- Sync drift: if the external audio runs longer or shorter than the video, expect drift at the end. Trim or pad the audio in an editor (e.g. Audacity) to match the video duration before loading it into Avidemux.
Copy vs re-encode: if both video and audio stay in Copy mode, replacing the audio is nearly instant and lossless — only the container is rewritten. If you need filters on the video side, you must re-encode anyway.
Frequently asked questions
How do I replace the audio track in Avidemux?
Open the video, go to Audio → Select Track, add your external audio file as a track, disable the original track, set Audio Output to an encoder (e.g. AAC (lav)) or Copy, and save the file.
Can I add an external M4A file as the audio track?
No — Avidemux does not accept audio wrapped in an MP4/M4A container as an external source. Convert the file to WAV or MP3 first (for example with FFmpeg) and load the converted file.
How many audio tracks does Avidemux support?
Avidemux 2.8.x supports up to 32 audio tracks per project, so you can keep the original audio and add dubbed or commentary tracks side by side.
Does replacing the audio require re-encoding the video?
No. If Video Output is set to Copy, the picture stream is passed through untouched and only the audio changes. You only need to re-encode when you also apply video filters.