3G2 to F4B Converter
Processing entirely on your device — large files may take a moment.
3G2 is the CDMA-era mobile video format — tiny, low-resolution clips from old feature phones. 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 3G2 compares to F4B
| 3G2 | F4B | |
|---|---|---|
| Compression | H.263 / baseline H.264 | Lossy AAC + chapters |
| Quality | Low resolution | Speech-optimized bitrates |
| Compatibility | Legacy CDMA phones | Apple Books, Audible |
| Best for | Old mobile clips | Chaptered audiobooks |
How to convert 3G2 to F4B
- 1
Select your files
Select your 3G2 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 3G2 format
3G2 is the 3GPP2 variant of the mobile video format family, born on CDMA networks (Verizon, KDDI) where 3GP ruled GSM sides. Structurally it is a cousin of MP4 carrying H.263 or H.264 baseline video with QCELP/EVRC or AMR audio.
It shares 3GP's fate: low-resolution clips trapped on old phones. Conversion to MP4 is lossless in spirit — the pixels simply move into a container every modern device accepts.
+Strengths
- ✓Tiny files for its era
- ✓Structurally close to MP4 — clean conversions
!Limitations
- −Low resolution and quality ceiling
- −Obsolete outside old CDMA phones
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 3G2 to F4B?
Converting makes sense where the strengths of F4B meet what 3G2 cannot give you. Chapter markers survive on Apple platforms Meanwhile Low resolution and quality ceiling One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this 3G2 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 3G2 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.
Does converting 3G2 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.
Why is video conversion slower than image conversion?
Every frame has to be decoded and re-encoded. This site runs that work on your own CPU via WebAssembly — nothing is uploaded, but a multi-minute video reasonably takes a few minutes. Images, by comparison, are single-frame jobs.