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CAF to OPUS converter

Convert CAF to OPUS in your browser. No upload and no account: the file never leaves your device, so the only size limit is your device’s memory.

I want OPUS
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Bytes of your files sent anywhere: 0 B

Related conversions

Other ways to convert CAF

Convert other formats to OPUS

Read more about the CAF format and the OPUS format, or see every audio tool and all audio conversions.

Should you convert CAF to OPUS?

A lossless move: CAF and OPUS both keep every sample, so the sound is identical and you can convert back at any time.

CAF is Apple’s professional audio container; OPUS is the most efficient audio codec in common use, especially for speech. Use Opus for speech and streaming where small size matters more than compatibility.

CAF and OPUS compared
Property CAF OPUS
Compression Depends on the codec inside Lossy
Typical quality PCM, AAC or ALAC 24–128 kbps
Support Mainly an Apple format Has patchy support
Best for Audio inside Apple apps and iOS development Voice notes, calls and streaming at low bitrates
Introduced 2005 2012

How to convert CAF to OPUS

  1. 01

    Add your CAF

    Drop your CAF file onto the box, or click to choose it. It is read from your disk and stays there.

  2. 02

    Check the settings

    The output is already set to OPUS. Change the bitrate if you want to; the defaults suit most files.

  3. 03

    Save the OPUS

    Press convert and save the OPUS. Several files come back together as a ZIP.

What changes when CAF becomes OPUS

Identical sound

Both formats are lossless, so the audio isn’t changed at all. Only the file size and which apps open it differ.

Opus runs at 48 kHz

Opus always works at 48 kHz internally, so other sample rates are converted. It sounds excellent at low bitrates, especially for voice.

A one-time engine download

CAF is decoded by FFmpeg compiled to WebAssembly, a 31 MB download the first time. After that it is cached, and the conversion never leaves your device.

Expect a much smaller file

CAF: Depends on the codec inside. OPUS: A minute of voice note is often under 200 KB. Shrinking the file is often the main reason to make this conversion.

This page is put together from our notes on each format, choosing only what is true of CAF and OPUS, so every pairing states the same facts the same way. How these pages are made.

Why it doesn’t upload

Recordings are often private: interviews, voice notes, unreleased music. Your browser can decode and encode audio itself, so there is no reason to send it anywhere.

How to check for yourself

Worth knowing

  • About the CAF. A CAF can hold uncompressed PCM, AAC or Apple Lossless, so two CAF files of the same length can differ tenfold in size.
  • About the OPUS. WhatsApp voice notes exported from a phone are Opus files, sometimes named .ogg, which many players and transcription services refuse.
  • MP3, WAV, M4A, OGG, Opus and FLAC are converted by your browser directly. WMA, AMR, APE, AC3 and the other specialist formats use the FFmpeg engine, a one-time 31 MB download.

Questions

Does converting CAF to OPUS lose quality?

OPUS is lossy, so a little is discarded, but at the default bitrate the difference is inaudible for nearly everyone.

Will an OPUS play in my car or on my phone?

OPUS has patchy support: browsers, Android and chat apps; many media players, editors and forms can’t open .opus files.

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