Convert CAF to WEBA — Free Online Tool
Convert CAF audio files to WEBA format by re-encoding the audio stream to Opus — a modern, royalty-free codec purpose-built for web streaming and browser playback. This is ideal for moving Apple-ecosystem audio (which no browser natively plays) into a universally browser-compatible format with excellent compression at low bitrates.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your CAF file here
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Settings
Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
CAF files commonly store audio as PCM (uncompressed) or AAC, neither of which browsers can play inside a WebM/WEBA container. This conversion decodes whatever audio codec is inside the CAF file and re-encodes it to Opus using the libopus encoder, then wraps the result in a WEBA container (the audio-only subset of WebM). Opus is a lossy codec, so this is a transcoding operation — not a lossless remux — and some audio quality is traded for dramatically smaller file sizes and near-universal browser support. The -vn flag is included as a safeguard to strip any non-audio data, keeping the output as a pure audio stream.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool. In this browser-based tool, FFmpeg runs locally via WebAssembly (ffmpeg.wasm), so no files leave your device. The same command works identically in a desktop FFmpeg installation for files over 1GB. |
-i input.caf
|
Specifies the input file — a CAF (Core Audio Format) file from Apple's ecosystem. FFmpeg will probe the container to identify the internal codec (PCM, AAC, FLAC, etc.) and decode it before re-encoding to Opus. |
-c:a libopus
|
Selects the libopus encoder for the audio stream, producing Opus-encoded audio — the modern, royalty-free codec required by WEBA and optimized for web streaming and browser playback at low-to-medium bitrates. |
-b:a 128k
|
Sets the Opus audio bitrate to 128 kilobits per second, which is the default and a good balance for music and voice content. Because Opus is highly efficient, 128k delivers quality comparable to AAC or MP3 at higher bitrates. |
-vn
|
Explicitly disables any video stream in the output. CAF is audio-only, but this flag ensures no unexpected data stream is passed through to the WEBA container, which is strictly an audio-only format. |
output.weba
|
Defines the output filename with the .weba extension, which tells FFmpeg to use the WebM muxer in audio-only mode. The WEBA container carries the Opus stream in a format that HTML5 browsers can play natively via the <audio> element. |
Common Use Cases
- Preparing Apple Logic Pro or GarageBand exported CAF recordings for use as audio assets on a website, where browsers require WebM/Opus for efficient streaming
- Converting CAF voiceover recordings from iOS apps into WEBA files for embedding directly in HTML5 audio players without any server-side transcoding
- Reducing the file size of large uncompressed PCM CAF files for web delivery — Opus at 128k typically produces files 10x smaller than CD-quality PCM
- Making Core Audio Format sound effects or music beds compatible with web game engines like Phaser or PixiJS, which prefer Opus-in-WebM for audio playback
- Archiving CAF podcast drafts or audio notes into a more web-portable format while retaining acceptable speech intelligibility at low bitrates like 64k
- Converting iOS screen recording audio (often saved as CAF) into a WEBA file for use in browser-based video editors or web presentations
Frequently Asked Questions
Yes — this is a lossy transcoding process. CAF files frequently contain uncompressed PCM or lossless audio, and re-encoding to Opus at 128k introduces some quality loss. That said, Opus is one of the most efficient lossy codecs available; at 128k it typically sounds transparent for music, and even 64k is acceptable for voice. If your source CAF already contains lossy AAC audio, converting to Opus adds a second generation of compression, which is more audible — keep the bitrate at 128k or higher in that case.
WEBA (Opus in a WebM container) is natively supported in Chrome, Firefox, Edge, and Opera without any plugins. Safari added WebM/Opus support in Safari 16 (macOS Ventura / iOS 16) released in 2022, so modern Safari versions handle it fine. Older Safari versions do not support WEBA, so if you need broad legacy compatibility, consider also providing an AAC fallback. For most modern web projects, WEBA/Opus is a safe and efficient choice.
Opus (libopus) is the default and preferred codec for WEBA because it outperforms Vorbis at nearly every bitrate, especially below 128k, and was specifically designed for internet streaming with low-latency encoding. Vorbis is an older codec and, while still valid inside a WebM/WEBA container, it offers no practical advantage over Opus today. You can substitute -c:a libvorbis if you need compatibility with a specific platform that supports Vorbis but not Opus, but this is rare.
Replace the value after -b:a in the command. For example, use -b:a 64k for a very small file suitable for speech, -b:a 192k for higher-fidelity music, or -b:a 320k for the highest quality option. Opus is extremely efficient, so the difference between 128k and 192k is subtle for most content. The full adjusted command would look like: ffmpeg -i input.caf -c:a libopus -b:a 192k -vn output.weba
FFmpeg will attempt to map compatible metadata tags from the CAF container to the WebM/WEBA output, but CAF uses Apple-specific metadata structures that do not always translate cleanly. Common tags like title and artist are usually carried over, but more specialized Core Audio metadata may be dropped. If precise metadata preservation is critical, verify the output with a tool like MediaInfo or ffprobe after conversion.
Yes. On Linux or macOS, you can loop over all CAF files in a directory with: for f in *.caf; do ffmpeg -i "$f" -c:a libopus -b:a 128k -vn "${f%.caf}.weba"; done — this processes each file individually and names the output to match the input. On Windows Command Prompt, use: for %f in (*.caf) do ffmpeg -i "%f" -c:a libopus -b:a 128k -vn "%~nf.weba". The in-browser tool on this page processes one file at a time.
Technical Notes
CAF (Core Audio Format) is Apple's professional audio container and supports a wide range of internal codecs including PCM variants (s16le, s24le, s32le, f32le), AAC, FLAC, Opus, Vorbis, and G.711 codecs like alaw and mulaw. WEBA, by contrast, only accepts Opus or Vorbis as its audio codec, which means this conversion always requires a full decode-and-reencode cycle regardless of what codec the source CAF contains — even if the CAF already contains Opus audio, FFmpeg will still transcode it by default to fit the WEBA muxer's requirements. File size reduction is often dramatic: a 24-bit 96kHz PCM CAF file could be 20–50x larger than its Opus-encoded WEBA equivalent at 128k. The WEBA format does not support chapters, embedded subtitles, or multiple audio tracks, so any such structures in a complex CAF file are silently discarded. Opus in WEBA also has an inherent algorithmic delay (typically around 6.5ms for the default complexity setting) which is negligible for music and podcasts but worth noting for timing-critical game audio use cases.