CAF → M4B
Convert CAF audio to M4B entirely in your browser — no upload, no watermark, no sign-up.
Drop files here
or browse from your device
images · audio · video · documents · archives · up to ~500MB
Your first conversion lands here automatically — saved on this device only, never uploaded.
100% Private
Runs in your browser. No upload.
Instant
No queue, no server roundtrip.
Offline-ready
Works after first load.
Moving CAF audio to M4B is about compatibility and size — which players accept the file and how much disk or bandwidth it costs once it gets there. M4B (MPEG-4 audiobook) earns its place here: bookmarking and chapter navigation built into the file itself. CAF is Apple's Core Audio container, built for recordings too long or large for WAV's 4 GB ceiling. Logic and iOS recording tools produce it.
CAF is Apple's Core Audio container, built for recordings too long or large for WAV's 4 GB ceiling. Logic and iOS recording tools produce it.
The audio is decoded and re-encoded, so the running time, channels and sample content stay intact while bitrate and file size follow M4B. Going from a compressed CAF file to any other lossy format is a second generation of compression — start from the highest-quality source you have when it matters, and expect a lossless target to grow the file rather than improve the sound.
What you gain with M4B: Bookmarking and chapter navigation built into the file itself.
Drop your CAF file above and Morphio decodes it locally, then re-encodes it as M4B using WebAssembly + the browser's native codecs. Nothing is ever uploaded — your files stay on your device. Batch as many files as your machine can handle. See exactly how in-browser conversion works.
Open the CAF to M4B page, drop your audio file on the drop zone and press convert. Morphio runs an FFmpeg build compiled to WebAssembly that runs inside the page, so the CAF data never leaves your device and no server ever receives a copy.
Sample rate and channel layout carry across, and you keep the original file untouched on disk. Converting CAF to M4B only rewrites the container and encoding you asked for — the source file on your disk is never modified.
Yes. The free plan covers 10 conversions a day with files up to 200 MB and adds no watermark or sign-up. Morphio Pro ($5/month, or $29 once for lifetime access) removes the daily cap and raises the per-file limit to 5 GB.
Morphio decodes the CAF file at full fidelity and re-encodes it at a high-quality M4B setting, so the difference is normally invisible or inaudible. What conversion cannot do is recover detail the original CAF file already threw away.
Yes — drop the whole batch in and each file is processed in turn on your own machine. The practical limit is your device's memory and patience, not a server quota, because nothing is queued anywhere else.
No. The conversion runs entirely inside your browser using WebAssembly, so the file never leaves your device — you can disconnect from the internet after the page loads and it still works.