F4B to W64 Converter
Processing entirely on your device — large files may take a moment.
Adobe Flash Audiobook (F4B) and Sony Wave64 exist for different jobs: F4B is Adobe's audiobook variant of the M4B container — the same chaptered AAC audio, Flash-era extension. Convert W64 recordings to WAV or FLAC for standard editors.
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 F4B compares to W64
| F4B | W64 | |
|---|---|---|
| Compatibility | Apple Books, Audible | Sony Vegas, ffmpeg, Sound Forge |
| Best for | Chaptered audiobooks | Long-duration uncompressed sessions |
How to convert F4B to W64
- 1
Select your files
Drag & drop your F4B files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to W64". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted W64 file individually, or grab everything at once as a ZIP archive.
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
About the W64 format
W64 is Sony's Wave64 — what happens when WAV's 32-bit size fields run out of road. A RIFF variant with 64-bit offsets, it shrugs off the 4 GB ceiling that makes plain WAV choke, which is why long field-recording sessions and Sony Vegas projects land in W64.
Inside, it is the same uncompressed PCM as WAV — ffmpeg hands W64 to WAV, FLAC or MP3 without touching a single sample, so conversion is purely about container compatibility.
+Strengths
- ✓No 4 GB size ceiling — hours-long recordings
- ✓Bit-exact PCM, same as WAV inside
- ✓Standard in Sony Vegas workflows
!Limitations
- −Almost nothing outside Sony tools opens it
- −Uncompressed — very large files
- −Legacy niche — new tools prefer RF64
Why convert F4B to W64?
There is a concrete reason this conversion exists: Chapters vanish in MP3 conversion W64 sidesteps that — No 4 GB size ceiling — hours-long recordings If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this F4B to W64 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 F4B to W64?
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 converting F4B to W64 reduce audio quality?
If W64 is lossless, the output contains everything the F4B file contains — no further loss is added. If W64 is lossy, one recompression pass is unavoidable; the quality slider controls how much. Loss that already happened in the source file can never be undone by converting.
Can I convert a whole folder of F4B files?
You can select many files at once and they are processed in a single batch. Output files land in one ZIP download when there is more than one result.