Pull the soundtrack out of a MP4 video as AU audio
Free and unlimited, and nothing is uploaded: it all runs in your own browser. Open Extract Audio
What changes when you convert MP4 to AU
- MP4 video is lossy and AU audio is lossless: converting cannot restore detail the source already discarded, and the AU audio file will usually be larger than the original.
- MP4 video animation cannot be expressed in AU audio; the first frame is converted as a still image.
- The video’s audio track is extracted and re-encoded to AU audio; video frames are discarded.
How to convert MP4 to AU
- Add your MP4 file — drag it onto the page or choose it. It stays on your device.
- Pick AU as the output format.
- Press convert and download the result — individually or as one ZIP.
Questions
How do I convert MP4 to AU for free?
Add your MP4 file on this site, choose AU, and press convert. The whole conversion runs in your own browser — nothing is uploaded — and the AU file downloads straight from your device.
Will converting MP4 to AU lose quality?
MP4 video is lossy and AU audio is lossless: converting cannot restore detail the source already discarded, and the AU audio file will usually be larger than the original.
Does AU keep everything MP4 supports?
Yes within the format’s own limits — animation is kept where the target supports it.