MyMediaTools

Convert VOB to CAF — Free Online Tool

Extract and convert audio from DVD VOB files into Apple's Core Audio Format (CAF), outputting uncompressed PCM audio (pcm_s16le) suitable for use in macOS and iOS audio workflows. This tool strips the MPEG-2 video and AC3/Dolby Digital audio tracks from the VOB container and delivers clean 16-bit PCM audio in a CAF file — all processed locally in your browser with no uploads required.

FFmpeg Command

Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg

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Estimated output:

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How It Works

VOB files from DVD-Video discs are complex multiplex containers, typically carrying MPEG-2 video alongside AC3 (Dolby Digital) audio, subtitle streams, and sometimes multiple audio tracks. During this conversion, FFmpeg discards the video stream entirely (since CAF is an audio-only format) and transcodes the AC3 audio into 16-bit signed little-endian PCM (pcm_s16le) — the default and most broadly compatible audio codec for CAF. The AC3 audio must be fully decoded and re-encoded as uncompressed PCM, which means this is not a simple remux; the audio is decoded from its lossy Dolby Digital encoding and written out as raw PCM samples. The resulting CAF file will be significantly larger than the original VOB's audio portion because PCM carries no compression, but it is immediately usable in Core Audio–based applications on macOS and iOS without any further decoding overhead.

What Each Flag Does

Flag What it does
ffmpeg Invokes the FFmpeg multimedia processing tool. In this browser-based tool, it runs as FFmpeg.wasm compiled to WebAssembly, executing entirely on your local machine without any server involvement.
-i input.vob Specifies the input VOB file. FFmpeg reads this DVD Video Object file, which contains a multiplexed stream of MPEG-2 video, AC3 audio, and possibly subtitle and menu data encoded per the DVD-Video specification.
-c:a pcm_s16le Sets the audio codec to 16-bit signed little-endian PCM, the default and most compatible uncompressed audio format for CAF files. This decodes the AC3 Dolby Digital audio from the VOB and re-encodes it as raw, uncompressed PCM samples — the format expected by Core Audio on macOS and iOS.
-b:a 128k Specifies a target audio bitrate of 128 kbps. For uncompressed PCM (pcm_s16le), this parameter has no practical effect on quality since PCM stores raw samples rather than compressed data — the actual bitrate is determined entirely by sample rate and bit depth. This flag is included for command consistency but does not alter the PCM output.
output.caf Defines the output file as a CAF (Core Audio Format) container. FFmpeg infers the container format from the .caf extension and writes the decoded PCM audio into a CAF file, which is natively readable by macOS, iOS, Logic Pro, GarageBand, and any application built on Apple's Core Audio framework.

Common Use Cases

  • Importing DVD audio content (commentary tracks, film scores, dialogue recordings) into Logic Pro or GarageBand, which natively read CAF files for audio editing and scoring workflows.
  • Archiving the audio portion of a home DVD — such as a recorded live event or family video — into a lossless-quality PCM CAF file for long-term storage on macOS systems.
  • Preparing audio extracted from a DVD-sourced VOB file for use in an iOS app or Xcode project, where CAF is the preferred container for uncompressed audio assets.
  • Isolating a specific language track from a multilingual DVD VOB file and converting it to CAF for use in a macOS dubbing or localization workflow.
  • Extracting music or spoken-word content from a concert or lecture DVD VOB file to edit and export as a podcast or album master in a Core Audio–native environment.
  • Converting DVD audio content to CAF as an intermediate step before mastering to a final delivery format, taking advantage of CAF's support for large file sizes without the 4GB limit imposed by WAV or AIFF.

Frequently Asked Questions

The AC3 audio in a VOB file is already a lossy Dolby Digital encoding, so some quality was lost when the DVD was originally authored. This conversion decodes that AC3 audio to uncompressed PCM, which is technically lossless at that point — no additional lossy compression is applied. The resulting CAF file represents the audio at full fidelity as it existed in the AC3 stream, but it cannot recover information discarded during the original AC3 encoding.
AC3 audio in DVD VOBs is heavily compressed — a typical 5.1 AC3 track at 448 kbps encodes what would otherwise be several megabytes of raw audio per second. When converted to pcm_s16le (uncompressed PCM), the audio is stored as raw 16-bit samples with no compression, resulting in files that can be 5–15x larger than the original AC3 data. This is expected and is why CAF supports large file sizes without the 4GB limit of older formats.
The FFmpeg command as written will select the first audio stream from the VOB file by default, which is typically the primary language track. VOB files from multilingual DVDs do contain multiple audio streams, but CAF does not support multiple audio tracks in a single file. To extract a specific language track, you would need to modify the command to add a stream selector such as -map 0:a:1 to choose the second audio track, then run the conversion again for each desired track.
If the source VOB contains a 5.1 AC3 track, FFmpeg will decode all six channels and write them out as 6-channel PCM in the CAF file. The channel layout (front left, front right, center, LFE, surround left, surround right) is preserved in the PCM output. macOS Core Audio supports multi-channel PCM in CAF, so the resulting file will retain the surround sound structure. However, playback of multi-channel CAF on some applications may depend on their individual support for 5.1 PCM.
To use AAC instead of uncompressed PCM, replace '-c:a pcm_s16le' with '-c:a aac' and set a bitrate with '-b:a 192k', giving the command: ffmpeg -i input.vob -c:a aac -b:a 192k output.caf. CAF supports AAC natively, and the resulting file will be much smaller than the PCM version. This is a good option if you need to reduce file size while keeping the output in CAF format for Apple ecosystem compatibility.
No. CAF is an audio-only container and does not support subtitles, chapter markers, or any video-related metadata. All subtitle streams, DVD chapter information, and the MPEG-2 video track are discarded during this conversion. If you need to preserve subtitles or chapters, you would need to extract them separately using a different tool or FFmpeg command targeting a container that supports those features.

Technical Notes

VOB files use the MPEG-PS (Program Stream) container format with the special VOB structure mandated by the DVD-Video specification, which is why FFmpeg requires the '-f vob' flag to correctly parse them. The default audio codec in DVD VOBs is AC3 (Dolby Digital), though some DVDs include DTS, LPCM, or MPEG audio tracks — this tool targets the default AC3 case. CAF (Core Audio Format) was designed by Apple to replace AIFF and WAV for professional audio use on macOS and iOS, with its primary advantages being support for files larger than 4GB and a flexible codec architecture. The default output codec pcm_s16le stores audio as 16-bit signed little-endian PCM samples, which is CD-quality depth and universally readable by Core Audio. One important limitation: this browser-based tool processes the entire VOB file in WebAssembly memory, and since VOB files from full DVD titles can be very large (up to 1GB supported here), processing time may be significant. For batch conversions of full DVD rips with multiple VOB files, the displayed FFmpeg command is particularly useful for running locally from the terminal, where you can also use shell scripting to loop over multiple files.

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