How do I convert MP4 to AU?

Drop your MP4 file onto the converter above, make sure AU is selected, and click Convert. When it's done, download the AU file — it usually takes a few seconds.

Is it safe to convert MP4 to AU here?

Yes. MP4 to AU conversion happens entirely inside your browser using WebAssembly, so your file is never uploaded to any server.

Is the MP4 to AU converter free?

Yes — free with no watermark. Signed-out visitors can convert 25 files a day, and a free account raises that to 250.

Will converting MP4 to AU reduce quality?

No — AU preserves the content of your MP4 file as faithfully as the format allows.

Can I convert multiple MP4 files at once?

Yes. Add up to 5 files at a time without an account, 10 with a free account and up to 500 on paid plans, then download them individually or as a single ZIP.

MP4→MP3 MP3→AU MP4→WebP MP4→MOV WAV→AU MP4→GIF MOV→AU MP4→WAV M4A→AU MP4→WebM WebM→AU MP4→MKV MP4→M4A MP4→AVI MP4→FLAC MP4→AAC MP4→OGG MP4→WMV MP4→Opus MP4→M4V MP4→FLV MP4→MPEG MP4→3GP MP4→WMA MP4→TS MP4→MPG MP4→AIFF MP4→AMR MP4→VOB FLAC→AU MKV→AU AAC→AU AVI→AU OGG→AU WMV→AU Opus→AU WMA→AU FLV→AU M4V→AU MPEG→AU 3GP→AU AIFF→AU AMR→AU MPG→AU TS→AU M4B→AU MTS→AU VOB→AU PNG→JPG JPG→PNG PNG→WebP JPG→WebP WebP→PNG WebP→JPG HEIC→PNG HEIC→JPG PNG→JPEG JPG→JPEG JPEG→PNG JPEG→JPG PNG→PDF JPG→PDF PDF→PNG PDF→JPG HEIC→WebP PDF→DOCX DOCX→PDF JPEG→WebP WebP→JPEG PNG→GIF JPG→GIF GIF→PNG GIF→JPG MOV→MP4 WebP→PDF HEIC→JPEG WebP→GIF GIF→WebP HEIC→PDF MP3→WAV WAV→MP3 JPEG→PDF PDF→JPEG SVG→PNG SVG→JPG HEIC→GIF MOV→MP3 GIF→MP4 JPEG→GIF GIF→JPEG PNG→AVIF JPG→AVIF AVIF→PNG AVIF→JPG MP3→M4A M4A→MP3 GIF→PDF SVG→PDF PNG→SVG JPG→SVG PDF→SVG SVG→WebP MOV→WebP WebM→MP4 WebP→AVIF AVIF→WebP WebP→SVG SVG→JPEG MKV→MP4 HEIC→AVIF JPEG→AVIF AVIF→JPEG JPEG→SVG MOV→GIF GIF→MOV WebM→MP3 AVIF→PDF MP3→FLAC FLAC→MP3 AVI→MP4 MKV→MP3 GIF→AVIF AVIF→GIF SVG→GIF GIF→SVG WebM→WebP MOV→WAV XLSX→PDF CSV→PDF EPUB→PDF PDF→EPUB MOV→WebM WebM→MOV MKV→WebP PNG→ICO JPG→ICO ICO→PNG ICO→JPG MP3→AAC WAV→M4A AAC→MP3 M4A→WAV AVI→MP3 MOV→MKV MKV→MOV MOV→M4A DOCX→EPUB EPUB→DOCX CSV→DOCX PDF→TXT DOC→PDF TXT→PDF WebP→ICO ICO→WebP PPTX→PDF AVI→WebP WebM→GIF GIF→WebM SVG→AVIF MOV→AVI

MP4AU

Convert MP4 to AU

Free and private: MP4 files are converted in your browser on computers; on phones, in our fast cloud and deleted automatically.

In your browser (fast cloud on phones)
No watermark
Batch & ZIP download

Need a smaller MP4? Compress MP4

How to convert MP4 to AU

1
Add your MP4 files
Drag and drop MP4 files onto the converter, paste them, or click to browse. You can add several at once.
2
Choose AU
AU is already selected. Open Options if you want to change quality, size or metadata.
3
Convert
Click Convert. Your files are converted right in your browser in seconds.
4
Download your AU
Download each AU file, or everything at once as a ZIP.

MP4 vs AU

From

MP4 · MPEG-4 Part 14

MP4 is the most widely supported video container. It usually holds H.264 or H.265 video with AAC audio and plays on every device and platform.

Type: Video
Extension: .mp4
MIME: video/mp4
Best for: sharing, streaming and uploading video anywhere

Lossy compressionOpen standard

All MP4 conversions →

AU · Sun Audio

AU is a simple audio format introduced by Sun Microsystems, common on early Unix systems and Java.

Type: Audio
Extension: .au
MIME: audio/basic
Best for: legacy Unix and Java applications

Legacy format

All AU conversions →

MP4 to AU: frequently asked questions

Free, private and in your browser

Convert MP4 to AU in seconds.

No sign-up, no watermarks, no waiting in line. Drop a file and get it back in the format you need.

Convert a file Explore the API

Most conversions never leave your device
Cloud files deleted automatically
No watermarks

Convert MP4 to AU

How to convert MP4 to AU

Add your MP4 files

Choose AU

Convert

Download your AU

MP4 vs AU

MP4 · MPEG-4 Part 14

AU · Sun Audio

Related conversions

Convert MP4 to other formats

Convert other formats to AU

MP4 to AU: frequently asked questions

Convert MP4 to AU in seconds.