DivX to AU Converter

DivX to AU Converter

DivX is an MPEG-4 Part 2 (ASP) video format — usually an AVI container carrying compressed video plus an MP3 or AC3 audio track. AU is the Sun/NeXT audio format (.au, sometimes .snd), a legacy Unix and Java sound container that typically holds uncompressed big-endian PCM or µ-law samples. This converter discards the video and writes the DivX audio track out as a standalone AU file — useful when an old Unix toolchain, a Java sun.audio player, or a legacy embedded system expects .au specifically.

DivX Format at a Glance

AU Format at a Glance

How to Convert DivX to AU

1. Upload Your DivX File: Drag and drop your .divx (or DivX-encoded AVI) onto the page, or click "Add Files" to pick it from your computer. Add several files to extract them in one batch.
2. Set Audio Sample Rate: Leave it on "Original" to keep the source rate, or pick a value (for example 8000 Hz to mimic classic µ-law AU, or 44100 Hz for CD-rate audio).
3. Set Audio Channel and Trim (Optional): Choose "Original", mono, or stereo under Audio Channel, and use the Trim controls if you only need a clip of the audio.
4. Convert and Download: Click Convert and download your .au file. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically after a few hours. No sign-up, no watermark.

Frequently Asked Questions

What is an AU file and what opens it?

AU (.au or .snd) is the Sun/NeXT audio format. It plays in cross-platform tools like VLC and Audacity, in older Unix audio utilities, and in Java programs through the sun.audio/javax.sound APIs. Most consumer media players and phones do not handle .au natively, which is why it is a legacy/niche choice rather than an everyday audio format.

Will converting DivX to AU improve the audio quality?

No. The audio inside a DivX file is almost always MP3 or AC3, which are lossy. Re-encoding that to AU — 8-bit µ-law by default, itself a telephony-grade companding — cannot restore detail the lossy codec already discarded. AU is the right pick only when something specifically requires the .au container — not as a quality upgrade.

Why is my AU file so much larger than the DivX?

Because the default AU encoding here is 8-bit µ-law, which stores one byte per sample per channel. At 44.1 kHz stereo that is about 706 kbps (~5.3 MB per minute) — several times the bitrate of a 128 kbps MP3 track — so the AU output is expected to be a few times bigger than the original compressed audio. Selecting 16-bit PCM doubles it again; a lower sample rate or mono keeps the file smaller.

Which encoding does the output AU use?

By default the converter writes 8-bit µ-law — the classic G.711 companding behind the historical 8000 Hz "Sparc-audio" sound. A-law and 16-bit big-endian linear PCM (PCM_S16BE) are selectable in the advanced options; pick PCM when you need a full-fidelity linear copy. A 60-second stereo track at 44100 Hz comes to roughly 5.3 MB as µ-law, or about 10 MB if you select 16-bit PCM.

My converted AU file is silent — what happened?

That usually means the source DivX had no audio track, or its audio stream was empty or corrupted. DivX-to-AU only extracts existing audio; it cannot create sound that was never there. Confirm the DivX actually plays with sound first, then re-run the conversion.

Should I use AU or a modern format like MP3?

For anything other than a legacy Unix/Java requirement, MP3 or M4A is the better choice — far smaller files and universal device support. Use DivX to MP3 to pull the audio into a compact, widely playable format instead. If you already have .au files to modernize, AU to MP3 goes the other way.

Is the conversion private?

Yes. Your file is uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours. There is no sign-up, no watermark, and your files are never shared or made public.

Should I pick PCM, µ-law, or A-law for the AU?

The default is µ-law — the classic 8-bit companded AU that old Unix and telephony playback expects; A-law is its European G.711 sibling. Both are lossy 8-bit encodings that keep the file small at the cost of dynamic range. Select 16-bit PCM (PCM_S16BE) in the advanced options when you want the cleanest linear copy of the audio and the receiving tool reads linear-PCM AU — most modern players and Audacity do.

Does the AU keep the original stereo, or downmix to mono?

By default it keeps the source layout — leave Audio Channel on "Original" and a stereo DivX track stays stereo in the AU. Switch Audio Channel to Mono if you want a single channel, which roughly halves the file size and is fine for speech or an already-mono source. AU supports both mono and stereo, so either choice writes a valid file.