AAC to CAF Converter
FileFlip converts AAC to CAF entirely inside your browser, using FFmpeg compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert an AAC file to CAF?#
- Drop your AAC file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to CAF and the conversion starts on its own. FileFlip downloads 30.8 MB of WebAssembly the first time and nothing after that, then runs FFmpeg on your own machine.
- Save the CAF file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting AAC to CAF lose quality?#
It depends on what is inside the file. AAC is a container rather than a codec, so whether the CAF conversion copies the streams across untouched or re-encodes them is decided by the codecs that particular file happens to use.
Is it safe to convert AAC files online?#
Yes, because nothing is uploaded. FileFlip converts AAC files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What AAC to CAF actually does to the file#
Converting AAC to CAF runs on FFmpeg, downloads 30.8 MB of WebAssembly the first time and nothing after that, re-encodes or copies through depending on the codecs in the file, and drops encoded streams.
| Engine | FFmpeg |
|---|---|
| Conversion path | One step: AAC → CAF |
| Downloaded to your browser | 30.8 MB, once, then cached by your browser |
| Quality | Decided by the codecs inside the file |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Encoded streams | Dropped | The target format has nowhere to put it. |
What is an AAC file?#
An AAC file, in this raw form, holds an ADTS bitstream of audio compressed with Advanced Audio Coding, the codec MPEG standardized in 1997 as a successor to MP3 that delivers better quality at the same bit rate.
Use raw AAC when a pipeline needs the bitstream itself, such as for streaming or broadcast, and per-file metadata isn't required.
Convert AAC to MP3 when a destination app or device doesn't support AAC playback, keeping in mind the conversion cannot add back what the original AAC encoding discarded.
What is a CAF file?#
A CAF file holds audio in Apple's Core Audio Format, introduced in 2005 to replace AIFF and WAV on the Mac because its 64-bit chunk sizes have no practical file size or duration limit.
Keep audio as CAF while it stays inside Apple's own tools, such as Logic Pro, GarageBand, or an iOS app's own audio recordings, where the format's size and codec flexibility are used directly.
Convert CAF to WAV or M4A when the audio needs to leave the Apple ecosystem, since most non-Apple software has no built-in way to open it.
AAC to CAF questions people ask#
What's the difference between AAC and MP3?
AAC is a newer, more efficient lossy codec than MP3. Standardized in 1997 versus MP3's 1993, it uses better psychoacoustic modeling to sound cleaner than MP3 at the same bit rate, especially below 128 kbps. Both throw away audio data permanently, so neither is a lossless upgrade over the other.
Is a .aac file the same as an M4A file?
No. Both usually hold AAC-compressed audio, but a .aac file is a raw ADTS bitstream with no container around it, while .m4a is that same AAC audio wrapped in an MP4 container that adds proper metadata support, seeking and chapter markers. Most consumer software expects the M4A version.
Does converting AAC to MP3 lose quality?
Yes, converting AAC to MP3 loses quality, because both are lossy codecs and the conversion has to decode the AAC and re-encode it in MP3's different, also lossy, format. The result carries artifacts from two compression passes instead of one, an effect known as generation loss.
What plays AAC files?
Apple's Music and QuickTime Player, VLC, and every modern browser and mobile OS play AAC audio, since it's the default codec for iTunes, YouTube and most streaming services. A raw .aac file specifically is less universally recognized than the same audio in an M4A container, so some players need it renamed or re-wrapped first.