Extract Audio from VOB to OGG — Free Online Tool
Extract audio from VOB DVD files and convert it to OGG Vorbis format — replacing the AC3 Dolby Digital audio track with an open, patent-free Vorbis stream. Ideal for archiving DVD audio content in a compact, widely-supported open format.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your VOB file here
or click to browse
Free — no uploads, no signups. Your files never leave your browser.
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
VOB files store audio as AC3 (Dolby Digital) streams, multiplexed alongside MPEG-2 video, subtitle tracks, and DVD menu data. This tool uses FFmpeg to demultiplex the VOB container, discard the video and subtitle streams entirely, and transcode the AC3 audio into OGG Vorbis using the libvorbis encoder. Because AC3 and Vorbis use fundamentally different perceptual audio compression algorithms, a full re-encode is required — there is no lossless passthrough option between these two codecs. The Vorbis encoder uses variable bitrate quality scaling (default quality level 4, approximately 128kbps) to produce an efficient, open-format audio file without any video overhead.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool, which handles the demultiplexing of the VOB container, decoding of the AC3 audio stream, and re-encoding to OGG Vorbis. |
-i input.vob
|
Specifies the input VOB file. FFmpeg will parse the MPEG-2 program stream structure of the VOB to identify all multiplexed streams — video, AC3 audio, and any subtitle tracks. |
-vn
|
Disables video output entirely, instructing FFmpeg to ignore the MPEG-2 video stream and any subtitle streams in the VOB. This is essential for audio extraction — without it, FFmpeg would attempt to include video in the output, which OGG cannot contain. |
-c:a libvorbis
|
Selects the libvorbis encoder to transcode the AC3 Dolby Digital audio from the VOB into Vorbis format, which is the standard open audio codec for OGG containers and is patent-free. |
-q:a 4
|
Sets the Vorbis variable bitrate quality level to 4 on a 0–10 scale, targeting approximately 128kbps VBR. This is the default balance between file size and audio fidelity; increase this value (e.g., '-q:a 7') when transcoding high-quality DVD surround audio where preserving dynamic range matters. |
output.ogg
|
Defines the output filename and signals FFmpeg to wrap the encoded Vorbis audio stream in an OGG container, producing a self-contained open-format audio file from the extracted DVD audio. |
Common Use Cases
- Ripping the audio soundtrack from a DVD concert or live performance VOB file to listen to on a media player that supports OGG but not AC3
- Archiving DVD audio commentary tracks as standalone OGG files for annotation or podcast-style listening
- Extracting dialogue or audio from a DVD training or educational disc to create open-format audio resources compatible with open-source media players like VLC or Audacious
- Converting DVD audio to OGG for use in open-source game engines or projects (like Godot) that natively support OGG Vorbis but not VOB or AC3
- Stripping multi-channel AC3 audio from VOB files to produce smaller, stereo-downmixed OGG files for web or mobile playback
- Preserving DVD audio content in a patent-free format as part of a digital archiving workflow using open standards
Frequently Asked Questions
It depends on the libvorbis encoder settings and your playback setup. Vorbis does support multi-channel audio, so the channel layout from the AC3 stream (e.g., 5.1 surround) can be encoded into the OGG file. However, many OGG players default to stereo playback, and the transcoding process from AC3 to Vorbis will re-encode the audio, which may slightly alter the spatial characteristics of the surround mix. If you need to preserve 5.1 channels explicitly, you may want to add '-ac 6' to the FFmpeg command.
Yes, there is generational quality loss because both AC3 and Vorbis are lossy codecs, and transcoding between two lossy formats always involves decoding the original compressed audio and re-encoding it with a new algorithm. The degree of loss depends on the quality level you choose for the Vorbis encoder. At the default quality level 4 (roughly 128kbps VBR), the result is generally transparent for most listeners, but for critical listening or archival purposes, using a higher quality level like 7 or 8 is recommended.
By default, FFmpeg selects the first audio stream it finds in the VOB file, which is typically the primary language track. VOB files from DVDs often contain multiple audio streams for different languages or commentary. To extract a specific track, add '-map 0:a:1' to the command (replacing '1' with the zero-based index of the desired audio stream). You can identify available streams by running 'ffmpeg -i input.vob' and reading the stream list in the output.
Adjust the '-q:a' value in the command to change the Vorbis quality level. The scale runs from 0 (lowest, ~64kbps) to 10 (highest, ~500kbps), with 4 being the default (approximately 128kbps VBR). For example, use '-q:a 6' for roughly 192kbps or '-q:a 8' for roughly 256kbps. Unlike AC3's fixed bitrate approach, Vorbis uses variable bitrate encoding, so '-q:a' controls quality rather than an exact bitrate, allowing the encoder to allocate more bits to complex passages automatically.
Yes. On Linux or macOS, you can run a shell loop: 'for f in *.vob; do ffmpeg -i "$f" -vn -c:a libvorbis -q:a 4 "${f%.vob}.ogg"; done'. On Windows Command Prompt, use: 'for %f in (*.vob) do ffmpeg -i "%f" -vn -c:a libvorbis -q:a 4 "%~nf.ogg"'. This is especially useful for extracting audio from a full DVD rip where the content is split across multiple VOB files like VTS_01_1.vob, VTS_01_2.vob, etc.
Subtitles are not carried over — the '-vn' flag discards all non-audio streams including subtitle tracks, and OGG does not support subtitle streams in any case. Chapter metadata from the VOB is also not automatically transferred, as VOB chapter data is typically stored in the IFO files alongside the VOB rather than within it. However, OGG does support chapter markers natively, and if chapter metadata is present in the VOB stream itself, FFmpeg may attempt to map it — though this is unreliable without the accompanying IFO file.
Technical Notes
VOB files are rarely standalone media — they are typically part of a DVD-Video structure where IFO (information) files define chapter points, audio stream mappings, and subtitle indices. When processing a VOB file in isolation without its IFO companion, FFmpeg may not correctly identify all audio streams or their language metadata. The default AC3 audio in VOB files is usually encoded at 192kbps or 384kbps for stereo, or up to 448kbps for 5.1 surround. Converting to OGG Vorbis at quality level 4 (roughly 128kbps VBR) will produce a smaller file with slight quality reduction relative to the source. The OGG container supports Vorbis comment-style metadata tags, but DVD-sourced VOB files often carry minimal embedded metadata, so fields like artist or album title may need to be added manually after conversion. If your VOB uses an AAC or MP3 audio track (less common but possible), the same command will still work correctly since FFmpeg handles the input codec detection automatically.