W64 to M4B Converter
Processing entirely on your device — large files may take a moment.
W64 (Sony Wave64) is WAV beyond its 4 GB ceiling — a 64-bit riff on the RIFF container that Sony Vegas and high-resolution field recorders emit for hours-long sessions. Converting M4B to MP3 frees audiobooks to play on car stereos, dumb players and anything without chapter support.
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 W64 compares to M4B
| W64 | M4B | |
|---|---|---|
| Compatibility | Sony Vegas, ffmpeg, Sound Forge | Apple Books, Audible |
| Best for | Long-duration uncompressed sessions | Chaptered audiobooks |
How to convert W64 to M4B
- 1
Select your files
Drag & drop your W64 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 M4B". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted M4B file individually, or grab everything at once as a ZIP archive.
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
About the M4B 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 W64 to M4B?
There is a concrete reason this conversion exists: Almost nothing outside Sony tools opens it M4B sidesteps that — Chapter markers survive on Apple platforms If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this W64 to M4B 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 W64 to M4B?
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.
Are tags like title and artist preserved?
Tag handling varies between target formats and this conversion focuses on the audio itself. For archival copies where tags matter, keep the original file; the converted copy is for playback and sharing.
Can I convert a whole folder of W64 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.