RM to AU Converter
FileFlip converts RM to AU entirely inside your browser, using FFmpeg compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert an RM file to AU?#
- Drop your RM file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to AU and the conversion starts on its own. FileFlip downloads 30.8 MB of WebAssembly the first time and nothing after that, then runs FFmpeg on your own machine.
- Save the AU file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting RM to AU lose quality?#
It depends on what is inside the file. RM is a container rather than a codec, so whether the AU conversion copies the streams across untouched or re-encodes them is decided by the codecs that particular file happens to use.
Is it safe to convert RM files online?#
Yes, because nothing is uploaded. FileFlip converts RM files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What RM to AU actually does to the file#
Converting RM to AU runs on FFmpeg, downloads 30.8 MB of WebAssembly the first time and nothing after that, re-encodes or copies through depending on the codecs in the file, and drops encoded streams and video tracks.
| Engine | FFmpeg |
|---|---|
| Conversion path | One step: RM → AU |
| Downloaded to your browser | 30.8 MB, once, then cached by your browser |
| Quality | Decided by the codecs inside the file |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Encoded streams | Dropped | The target format has nowhere to put it. |
| Video tracks | Dropped | The target format has nowhere to put it. |
What is an RM file?#
An RM file is a RealMedia container from RealNetworks, holding RealVideo and RealAudio streams built for the dial-up era, when RealPlayer was how most people first watched video over the internet.
There is no current reason to create a new RM file; it only shows up now as something to get footage out of.
Convert RM to MP4 as soon as one turns up, since RealPlayer support keeps shrinking and most other software cannot open the format at all.
What is an AU file?#
An AU file holds audio in Sun Microsystems' Unix workstation format, a plain header followed by raw sample data that was the standard system-alert and early web audio format before WAV and MP3 took over.
AU still shows up as the format Java's javax.sound and some Unix system tools default to for short sound effects, where its simplicity is the point.
Convert AU to WAV or MP3 when the audio needs to play in modern media players, browsers, or editing software that no longer ship AU support by default.
RM to AU questions people ask#
What still opens an RM file?
VLC opens most RM files on Windows, macOS and Linux through its built-in libavformat decoder, which covers the common RealVideo codecs. RealPlayer itself still exists for Windows, Android and iOS, but RealNetworks stopped releasing it for macOS in 2018.
What should I convert an old RM file to?
MP4 with H.264 is the safe target for an old RM file, since it plays everywhere RealMedia no longer does, from phones to browsers to any current editing software.
Is RealMedia still used for anything?
No. RealMedia was the dominant streaming format before broadband made Flash and later HTML5 video practical, and it has had no meaningful new use since. An RM file today is almost always old footage someone is trying to recover, not something being created.
What creates an AU file?
AU files come from Unix and Sun workstation software, from Java's built-in sound APIs, and from older system sound effects, since AU was the default audio format on SunOS and NeXT machines. Websites in the 1990s also used it for embedded sound clips before WAV and MP3 became standard.