DivX to F4B Converter
Processing entirely on your device — large files may take a moment.
DivX is the MPEG-4 ASP profile that defined movie sharing and DVD-player compatibility in the 2000s — most "AVI movies" of the era are DivX. Convert F4B audiobooks exactly like M4B — to MP3, M4A or WAV.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How DivX compares to F4B
| DivX | F4B | |
|---|---|---|
| Compatibility | ffmpeg, DivX players, VLC | Apple Books, Audible |
| Best for | 2000s movie library migration | Chaptered audiobooks |
How to convert DivX to F4B
- 1
Select your files
Select your DivX video.
- 2
Convert instantly
The engine demuxes the container and encodes the audio track into your chosen format.
- 3
Download results
Download the F4B audio — the video track is simply dropped.
About the DivX format
DivX was the codec that made movie-sharing possible on a CD-R: MPEG-4 ASP at a bitrate that fit a 90-minute film into 700MB. The .divx container is DivX's own variant of AVI with chapter and menu extensions, and a decade of downloaded movies carry it.
Conversion to MP4 is straightforward — the MPEG-4 ASP video decodes through ffmpeg and re-encodes to H.264 at half the size for phones and smart TVs that never learned the DivX profile.
+Strengths
- ✓Enormous installed base of content
- ✓Hardware players supported it for a decade
- ✓Decodes cleanly via ffmpeg
!Limitations
- −QPEL/GMC profiles break some decoders
- −MPEG-4 ASP artifacts at low bitrates
- −Superseded by H.264 everywhere
About the F4B format
M4B is M4A wearing an audiobook badge: the same AAC audio in an MP4 container, plus chapter markers that Apple Books and Audible apps render as a scrubbing timeline. Buy an audiobook outside Audible and it likely arrives as M4B.
The format is deliberately chained to Apple's book ecosystem. Converting M4B to MP3 sets the book free: car stereos, gym players, old iPods and every app without chapter support will play it — though the chapter marks themselves are flattened away.
+Strengths
- ✓Chapter markers survive on Apple platforms
- ✓Efficient AAC audio
!Limitations
- −Chapters vanish in MP3 conversion
- −Non-Apple support is patchy
Why convert DivX to F4B?
Think of it as moving your file to the container that fits the job. QPEL/GMC profiles break some decoders F4B works differently: Chapter markers survive on Apple platforms If any of that sounds like your task, run the conversion — it takes seconds and nothing leaves your device.
Frequently asked questions
Is this DivX to F4B 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 DivX to F4B?
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 F4B, staying in sync with the video. If your DivX file has multiple audio tracks, the first one is used.
Does converting DivX to F4B 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.