An .m4a file is actually an MPEG-4 container wrapping an AAC audio stream. Because Avidemux cannot invoke a demuxer for an external track, it fails to open it. It requires a raw AAC stream wrapped in an ADTS envelope instead.
Take the resulting .mkv file (which now contains your audio track) and load it as your audio source in Avidemux via Audio -> Select Track -> Add audio track . Method 3: Change the Avidemux Audio Output Device
: Avidemux cannot use audio stored in an MP4 container (like avidemux+cannot+use+that+file+as+audio+track
This error is frustrating because it halts your workflow immediately, and the error message itself offers very little explanation. If you are staring at this prompt, don't worry. It is rarely a sign of a broken installation. Instead, it is usually a technical mismatch between your video project settings and the audio file you are trying to import.
For advanced users or those dealing with batch files, is a rapid tool to sanitize the audio file. Running a simple copy or re-encode command fixes the broken container structure instantly. Take the resulting
: Avidemux is most stable with uncompressed PCM (WAV) files. Use a tool like to convert your audio file to a 16-bit PCM WAV before importing. Check the Sampling Rate
– Avidemux can be picky with VBR in external files It is rarely a sign of a broken installation
If you do not have Audacity, you can use to quickly transcode the audio into a standard format. Open VLC and go to Media > Convert / Save .
You are trying to load a MP3 file into a project where Audio Output is set to "AAC" . Avidemux tries to copy the MP3 as AAC, which is impossible. Alternatively, you load a FLAC file when Audio Output is set to "Copy" while outputting to an MP4 container (which doesn’t support FLAC).