If you just need to merge an audio file with a video without re-encoding, MKVToolNix is often more robust for "multiplexing" external tracks into MKV files without these strict format restrictions. Correct Workflow in Avidemux Once you have a compatible raw file (like a .wav ): How to add audio to a muted/silent video with avidemux
By setting Audio Output to “AAC” instead of “Copy,” Avidemux stops trying to preserve the original audio format and instead creates a brand new, container-friendly audio stream. avidemux cannot use that file as audio track
Q: What audio formats are supported by Avidemux? A: Avidemux supports WAV, AIFF, MP3, and AAC audio formats. If you just need to merge an audio
In plain terms, Avidemux is telling you: “I recognize this file, but I cannot read its audio data in a way that lets me edit or merge it with your video.” A: Avidemux supports WAV, AIFF, MP3, and AAC audio formats