FLV to AU Converter
Processing entirely on your device — large files may take a moment.
Flash Video and Sun Microsystems Audio exist for different jobs: FLV is the Flash-era video container from thousands of old video sites and screen recordings. Modern players have dropped it. Converting AU to WAV preserves the samples in a format every modern tool reads.
This converter runs entirely in your browser using WebAssembly — your files never leave your device, nothing is uploaded, and there are no watermarks, sign-ups or queues. Drop in several files at once to convert them as a batch.
How FLV compares to AU
| FLV | AU | |
|---|---|---|
| Compression | VP6 / H.264 legacy | µ-law or PCM |
| Quality | Of its era | Mono voice-grade (µ-law) |
| Compatibility | Legacy players only | Legacy Unix tools |
| Best for | Early web video archives | Old system sounds and recordings |
How to convert FLV to AU
- 1
Select your files
Select your FLV video.
- 2
Convert instantly
The engine demuxes the container and encodes the audio track into your chosen format.
- 3
Download results
Download the AU audio — the video track is simply dropped.
About the FLV format
FLV (Flash Video) was the video format of the early streaming web — YouTube's original delivery container from 2005 to ~2010, played by Adobe Flash Player. Later versions carried H.264/AAC, but the container lived and died with Flash, which reached end-of-life in 2020.
Modern browsers cannot play FLV at all, and only niche players (VLC) bother. If you have an FLV archive, converting to MP4 recovers the same H.264 video into a container every device accepts.
+ Strengths
- ✓Only relevant for early-web video archives
! Limitations
- −Dead ecosystem — Flash ended in 2020
- −No browser support at all
About the AU format
AU is Sun Microsystems' audio format from the Unix workstation age: a small header followed by µ-law (or PCM) samples. Java's applet era shipped it everywhere, and old Unix sound tooling still emits it.
Modern players increasingly skip it. Converting AU to WAV preserves the samples bit-for-bit while moving the file into universal territory — the standard rescue path for system sounds and old recordings.
+ Strengths
- ✓Simple, lossless sample storage
- ✓Native to old Unix/Java tooling
! Limitations
- −µ-law flavor sounds dated and mono
- −Dropped by modern players
Why convert FLV to AU?
Converting makes sense where the strengths of AU meet what FLV cannot give you. Simple, lossless sample storage Meanwhile Dead ecosystem — Flash ended in 2020 One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this FLV to AU converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for FLV to AU?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
Will the audio track be kept?
Yes. The audio is carried over and re-encoded to the standard audio codec of AU, staying in sync with the video. If your FLV file has multiple audio tracks, the first one is used.
Does converting FLV to AU re-encode my video?
Yes. The video is decoded and re-encoded with the settings chosen by the quality slider, which is what allows the format and size to change. For an archival copy, keep higher quality; for sharing, lower quality gives a much smaller file.