MyMediaTools

Convert MOV to CAF — Free Online Tool

Extract and convert audio from MOV video files into CAF (Core Audio Format), Apple's professional audio container built to handle large files and high-resolution audio without the size limitations of AIFF or WAV. The audio stream is transcoded to uncompressed PCM (16-bit little-endian), making the output immediately usable in Logic Pro, GarageBand, and other Apple audio tools.

FFmpeg Command

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How It Works

MOV files store audio in a multiplexed stream alongside video, chapters, and other tracks. This conversion strips the video, subtitle, and chapter data entirely, extracting only the audio stream and re-encoding it as 16-bit signed little-endian PCM (pcm_s16le) inside a CAF container. Because MOV commonly stores audio as AAC or another compressed codec, this process involves actual decoding and re-encoding — it is not a simple remux. The result is an uncompressed audio file inside CAF's extensible wrapper, which supports files larger than 4GB (unlike WAV) and is natively recognized by macOS and iOS audio frameworks including Core Audio and AVFoundation.

What Each Flag Does

Flag What it does
ffmpeg Invokes the FFmpeg program. This is the same open-source engine running inside the browser via WebAssembly — the command shown is identical to what you would run in a local terminal on macOS, Linux, or Windows.
-i input.mov Specifies the input file — a MOV container that may hold video, one or more audio tracks, chapter markers, and subtitle streams. FFmpeg reads all streams from this file and selects which ones to process based on the rest of the command.
-c:a pcm_s16le Sets the audio codec for the output to 16-bit signed little-endian PCM, the standard uncompressed audio format used by Core Audio on Apple platforms. This decodes whatever compressed audio (e.g., AAC) was in the MOV and writes raw, uncompressed samples into the CAF file.
-b:a 128k Specifies a target audio bitrate of 128 kilobits per second. For the PCM codec selected here, this flag has no practical effect since PCM is uncompressed and its bitrate is fixed by sample rate and bit depth — it becomes meaningful only if you substitute a variable-bitrate codec like AAC or Opus.
output.caf Defines the output file name and tells FFmpeg to write a CAF (Core Audio Format) container. FFmpeg infers the container format from the .caf extension, wrapping the PCM audio stream in Apple's extensible audio container that supports files larger than 4GB.

Common Use Cases

  • Extracting a clean, uncompressed audio stem from a Final Cut Pro or Premiere Pro MOV export for mastering in Logic Pro
  • Converting a MOV interview recording into a CAF file for import into GarageBand on Mac or iPad without format compatibility issues
  • Archiving the audio track of an Apple ProRes MOV file as a lossless PCM CAF for long-term storage without lossy compression artifacts
  • Pulling dialogue or voiceover audio from a MOV camera file to hand off to a sound editor working in an Apple-native audio pipeline
  • Converting a large MOV recording (over 4GB audio equivalent) to CAF to avoid the file size ceiling imposed by WAV and AIFF formats
  • Preparing audio content from MOV screen recordings for use in Xcode-based iOS app bundles, where CAF is a preferred format for system audio assets

Frequently Asked Questions

It depends on the original audio codec in the MOV file. If the MOV contains AAC or another compressed codec, the conversion decodes that lossy audio and re-encodes it as uncompressed PCM — the PCM output itself introduces no further compression loss, but any quality reduction from the original AAC encoding is already baked in and cannot be recovered. If the MOV was recorded with uncompressed PCM audio at a higher bit depth (such as 24-bit), downconverting to 16-bit pcm_s16le will reduce dynamic range slightly. Use pcm_s24le in the command if you want to preserve 24-bit source audio.
MOV files almost always store audio in a compressed format like AAC, which achieves significant size reduction through lossy compression. When that audio is decoded and written as uncompressed PCM inside CAF, the file size reflects raw, uncompressed audio data — typically around 10MB per minute for stereo 16-bit 44.1kHz audio. This is expected behavior and not an error. CAF's advantage is its ability to hold these large uncompressed files without the 4GB ceiling that breaks WAV and AIFF files.
Most metadata embedded in the MOV container — such as QuickTime user data atoms for title, artist, or creation date — is not automatically carried over to the CAF output during this conversion. CAF has its own metadata chunk structure, but FFmpeg's MOV-to-CAF pipeline does not map QuickTime metadata to CAF metadata atoms by default. If preserving metadata is important, you should manually tag the CAF file after conversion using a tool like afinfo or a metadata editor that understands CAF's chunk format.
Yes — CAF with PCM audio is one of Apple's recommended formats for app audio assets and is fully supported by AVAudioPlayer, AVFoundation, and the Audio Toolbox framework on both macOS and iOS. Uncompressed PCM in CAF offers the lowest decode latency, which is particularly useful for short UI sounds and game audio. For larger assets where file size matters, you may want to re-encode the CAF using AAC or IMA4 compression before adding it to your Xcode project.
Replace '-c:a pcm_s16le' with your desired codec. For AAC, use '-c:a aac -b:a 192k'; for FLAC lossless, use '-c:a flac'. For example: 'ffmpeg -i input.mov -c:a flac output.caf'. CAF supports AAC, FLAC, Opus, Vorbis, and several PCM variants (pcm_s16le, pcm_s24le, pcm_s32le, pcm_f32le). Choose AAC if you need a smaller file with acceptable quality loss, or FLAC if you want lossless compression that is significantly smaller than uncompressed PCM.
On macOS or Linux, wrap the command in a shell loop: 'for f in *.mov; do ffmpeg -i "$f" -c:a pcm_s16le "${f%.mov}.caf"; done'. This iterates over every MOV file in the current directory, strips the video track, and writes a matching CAF file with the same base name. On Windows Command Prompt, use: 'for %f in (*.mov) do ffmpeg -i "%f" -c:a pcm_s16le "%~nf.caf"'. The in-browser tool processes one file at a time, so the FFmpeg command is the practical choice for bulk conversions.

Technical Notes

CAF was designed by Apple specifically to replace AIFF and WAV in professional workflows, removing the 4GB file size limit and adding support for multiple audio channels, arbitrary sample rates, and a flexible chunk-based metadata structure. When converting from MOV, FFmpeg discards all video streams, subtitle tracks, chapter markers, and secondary audio tracks — CAF is a single-stream audio container with no support for multiplexed video or multiple audio tracks. The default output codec, pcm_s16le, produces 16-bit signed little-endian PCM, which is CD-quality and universally readable by Core Audio on all Apple platforms. If the source MOV contains 24-bit or 32-bit audio (common in professional ProRes MOV files from DaVinci Resolve or Final Cut Pro), switching to pcm_s24le or pcm_s32le preserves the full bit depth. The '-b:a 128k' flag in the command is effectively ignored for PCM codecs since PCM is an uncompressed format with a fixed bitrate determined by sample rate and bit depth — it only becomes relevant if you switch to a variable-bitrate codec like AAC or Opus. CAF files produced by FFmpeg are fully compatible with macOS's built-in afplay, afconvert, and QuickTime Player, as well as Logic Pro and GarageBand.

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