MOV to AU Converter

MOV to AU Converter

This tool extracts the audio track from a QuickTime MOV video and saves it as an AU (.au / .snd) file — the legacy Sun Microsystems and NeXT sound format. The video stream is discarded; only the audio is kept. Convert to AU when a specific Unix, Solaris, or Java workflow expects a .au file rather than a modern container like MP3 or WAV.

AU (.au / .snd) Format at a Glance

MOV (QuickTime) Source at a Glance

How to Convert MOV to AU

1. Upload Your MOV File: Drag and drop your .mov file onto the page, or click "+ Add Files" to browse from your computer.
2. Set Audio Sample Rate: Leave it as "Original" to match the source, or choose a fixed rate (8000 Hz reproduces the classic µ-law system-sound profile; 44100 Hz preserves CD-quality audio).
3. Set Audio Channel and Trim (Optional): Pick Mono or Stereo, and use Trim to export only a start time and duration instead of the whole clip.
4. Convert and Download: Click "Convert" and download your AU file. No sign-up, no watermark.

Frequently Asked Questions

What programs can open a .au file?

Java applications open .au natively — the Java Sound API (javax.sound.sampled) supports AU, SND, AIFF, and WAV without any extra library, which is why Java applets historically used AU for system sounds. On the desktop, VLC, Audacity, and FFmpeg all read AU. If a player refuses it, the file is likely an uncommon encoding (24-bit or float PCM) rather than the standard µ-law or 16-bit profile.

What encoding does the AU file use?

AU is a container that can hold several encodings: 8-bit µ-law and A-law companding (ITU-T G.711), 8/16/24/32-bit linear PCM, and 32- or 64-bit IEEE floating point. The historic default is 8-bit µ-law at 8000 Hz, mono — the format originally shipped headerless in exactly that profile on Sun and NeXT systems before the 24-byte header was standardized. This converter also writes 8-bit µ-law by default (at the sample rate and channel layout you choose); A-law and 16-bit big-endian linear PCM (PCM_S16BE) are selectable in the advanced options.

Will converting MOV to AU lose quality?

Going from a compressed MOV audio track (usually AAC) to AU is a decode-then-re-encode step, so it inherits the lossy compression already in the source — it does not add a second lossy pass if you select a linear PCM profile. The default output, though, is 8-bit µ-law — telephony-grade companding that is a real quality reduction for music. For a faithful copy, keep the sample rate at "Original" and select 16-bit PCM (PCM_S16BE) in the advanced options.

Why would I convert to AU instead of WAV or MP3?

Only convert to AU when something specifically requires it: a Java program loading a bundled .au clip, a legacy Solaris or SunOS workflow, or a telephony pipeline that expects raw µ-law samples. For general playback, sharing, or editing, WAV (lossless) or MP3 (small, universal) are better choices — see MOV to WAV or MOV to MP3.

How big is an AU file compared to the MOV?

It depends entirely on the encoding. An 8-bit µ-law 8000 Hz mono AU is tiny — roughly 8 KB per second of audio — because µ-law packs each sample into a single byte. A 16-bit PCM AU at 44100 Hz stereo is far larger, near 176 KB per second, since it stores uncompressed samples. In our testing, a 60-second MOV exported to 8-bit µ-law 8000 Hz mono AU produced a file under 500 KB, while the same clip at 16-bit 44100 Hz stereo exceeded 10 MB.

Is the AU format still maintained or standardized?

No formal body actively maintains it today; AU is a stable legacy format whose structure has been documented and unchanged for decades. It remains useful precisely because it is simple and predictable — a fixed 24-byte big-endian header followed by raw samples — which is why it persists in Java tooling and parts of scientific audio computing. If you need a current, widely supported target instead, our Audio Converter re-encodes AU into MP3, WAV, FLAC, and other modern formats.

Can I export only part of the MOV's audio to AU?

Yes. Use the Trim control to set a start time and a duration, and only that segment of the audio track is written to the AU file — handy when you want a single sound effect or a spoken line rather than a whole recording. Everything outside the trimmed range is left out of the output, and the source MOV itself is never altered.

Does the AU file support stereo, or only mono?

Both. The AU/SND container has always carried a channel count in its header, so it can hold mono or stereo audio. The historic Unix system-sound default was 8-bit µ-law at 8000 Hz in mono, which is why AU is so associated with mono telephony samples — but if your MOV has a stereo track, set the Audio Channel option to Stereo and the AU keeps both channels intact.

Are my files kept private?

Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public.