Avidemux Cannot Use That — File As Audio Track

If your external audio is already in a compatible format but Avidemux still complains, try creating a "dummy" audio track first.

Before diving into fixes, it’s crucial to understand how Avidemux handles audio. Unlike professional editors like DaVinci Resolve or Premiere Pro, Avidemux does not perform "on-the-fly" audio transcoding or extensive format negotiation.

Avidemux operates on a direct stream copy principle by default. This means it tries to copy audio data directly from the source file (or external track) to the output without re-encoding. For this to work, the audio format must be compatible with the video container (MKV, MP4, AVI) you are using. avidemux cannot use that file as audio track

When you see "Cannot use that file as audio track," Avidemux is essentially saying: “I cannot mux this audio stream into the selected video container without re-encoding, and my current audio output settings do not allow re-encoding, or the audio format is unsupported.”

While modern video tools handle VBR well, Avidemux can struggle with VBR MP3 or AAC files as external tracks. Because VBR files have inconsistent frame-to-frame bitrates, Avidemux cannot calculate exact sync points when muxing, leading to rejection. If your external audio is already in a

Avidemux is a beloved, free, and open-source video editor, primarily used for simple cutting, filtering, and encoding tasks. Its lightweight nature and non-linear workflow make it a go-to tool for quick edits. However, users frequently encounter a frustrating roadblock: the dreaded red error message at the bottom of the interface: "Cannot use that file as audio track."

This error typically appears when you try to load an external audio file (like an MP3, M4A, or AAC) to replace or add a new audio track to a video. Instead of seamlessly integrating the sound, Avidemux rejects the file entirely. While modern video tools handle VBR well, Avidemux

Why does this happen? Is the file corrupt? Is Avidemux broken? The answer is usually more technical but entirely fixable. This article will explore every possible cause and provide step-by-step solutions.

This is the culprit in 80% of cases. If your video is in an MP4 container 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.