MyMediaTools

Convert VOB to WEBA — Free Online Tool

Extract and convert audio from DVD VOB files into WEBA format using the Opus codec — perfect for getting high-quality, web-optimized audio from DVD rips. VOB files contain multiplexed MPEG-2 video and AC3 surround audio; this tool strips the video and transcodes the AC3 audio stream to Opus inside a WebM container.

FFmpeg Command

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

Free — no uploads, no signups. Your files never leave your browser.

Estimated output:

Conversion Complete!

Download

How It Works

VOB files are DVD container files that bundle together MPEG-2 video, AC3 (Dolby Digital) audio, subtitle streams, and sometimes multiple audio tracks into a single multiplexed stream. During this conversion, FFmpeg demultiplexes the VOB container, discards the MPEG-2 video stream entirely (using the -vn flag), and transcodes the AC3 audio — typically a multichannel 5.1 surround mix — into Opus audio encoded at 128k bitrate. Opus is a modern, highly efficient lossy codec that often outperforms MP3 and AAC at equivalent bitrates, especially below 128k. The resulting WEBA file is a WebM audio-only container, which is natively supported in modern browsers like Chrome and Firefox. Because AC3 and Opus are fundamentally different codecs, full re-encoding is required — this is not a lossless remux.

What Each Flag Does

Flag What it does
ffmpeg Invokes the FFmpeg command-line tool, which handles all the demultiplexing, decoding, encoding, and remuxing required to convert the VOB file to WEBA format in this pipeline.
-i input.vob Specifies the input DVD VOB file. FFmpeg will automatically detect the multiplexed MPEG-2 video and AC3 audio streams (along with any subtitle streams) contained within the VOB container.
-c:a libopus Selects the Opus audio encoder for the output. The source AC3 audio from the VOB is fully decoded to PCM and then re-encoded with Opus — a modern, royalty-free codec optimized for web streaming that outperforms AC3 at equivalent or lower bitrates.
-b:a 128k Sets the Opus audio bitrate to 128 kilobits per second. For stereo audio decoded from a DVD's AC3 track, 128k Opus delivers transparent or near-transparent quality; for multichannel 5.1 sources, consider downmixing to stereo first to get the full benefit of this bitrate.
-vn Disables video output entirely, stripping the MPEG-2 video stream from the VOB so that only audio is written to the output. This flag is mandatory because the WEBA container is audio-only and cannot hold a video stream.
output.weba Specifies the output file with a .weba extension, which signals FFmpeg to write a WebM audio-only container (WEBA) holding the encoded Opus audio stream — the standard delivery format for Opus audio on the web.

Common Use Cases

  • Extract the musical score or dialogue from a DVD rip to create a web-embeddable audio track for a film studies or educational website
  • Convert AC3 5.1 surround audio from a DVD VOB into a compressed Opus WEBA file for streaming in a browser-based media player
  • Archive the audio commentary track from a DVD (stored as a secondary AC3 stream in the VOB) in a lightweight, modern format for long-term storage
  • Pull the audio from a DVD concert or live performance VOB file to create a standalone audio recording for web playback without the overhead of video
  • Reduce the file size of a DVD audio rip significantly — Opus at 128k delivers quality comparable to AC3 at 192k or higher, saving bandwidth for web delivery
  • Prepare DVD-sourced audio content for use in a web application or Progressive Web App (PWA) where WebM/Opus is the preferred audio format

Frequently Asked Questions

By default, FFmpeg will attempt to encode all channels from the AC3 source into Opus, but Opus handles channel layouts differently than AC3 Dolby Digital. If your VOB contains a 5.1 AC3 track, Opus can encode it as multichannel audio, but WEBA playback in browsers is typically stereo. For web use, you may want to add -ac 2 to the command to explicitly downmix to stereo, which also allows a lower bitrate like 96k or 128k to be more effective. Without downmixing, a 128k bitrate spread across six channels will sound noticeably worse than 128k for stereo audio.
By default, FFmpeg selects the first audio stream it encounters in the VOB file, which is usually the primary language track. VOB files on DVDs commonly carry multiple AC3 audio streams for different languages. To target a specific track, add -map 0:a:1 to the command (where 0 is the first for English, 1 for the second track, etc.) before the output filename. WEBA does not support multiple audio tracks, so only one stream can be included in the output file.
The audio bitrate is controlled by the -b:a flag in the command. The default is 128k, which provides good quality for stereo Opus audio. For speech-heavy content like commentary tracks, you can reduce this to 96k or even 64k and still get excellent intelligibility due to Opus's efficiency. For music or high-fidelity audio from a DVD concert, consider increasing to 192k or 256k. Replace 128k in the command with your desired value: ffmpeg -i input.vob -c:a libopus -b:a 256k -vn output.weba.
Yes. On Linux or macOS, you can run a shell loop: for f in *.vob; do ffmpeg -i "$f" -c:a libopus -b:a 128k -vn "${f%.vob}.weba"; done. On Windows Command Prompt, use: for %f in (*.vob) do ffmpeg -i "%f" -c:a libopus -b:a 128k -vn "%~nf.weba". Note that DVDs are often split across multiple VOB files (VTS_01_1.vob, VTS_01_2.vob, etc.) representing a single title — if you want to concatenate these first, use FFmpeg's concat demuxer before running the conversion.
Yes, this is a lossy-to-lossy transcode, meaning there is a generational quality loss. The AC3 audio in the VOB is first decoded to uncompressed PCM, then re-encoded with Opus. Both codecs are lossy, so some audio information is discarded at each stage. However, Opus is a significantly more modern and efficient codec than AC3 — at 128k bitrate, Opus typically sounds better than AC3 at 192k. If the source AC3 track is high bitrate (e.g., 448k), the output at 128k Opus will still represent a quality reduction, but one that is largely imperceptible for typical listening.
No. WEBA is a WebM audio-only container and does not support subtitle streams of any kind. Even though the source VOB file may contain DVD subtitle tracks (stored as bitmap-based subpicture streams), all subtitle data is discarded during this conversion. If you need subtitles alongside the audio for web use, you would need to extract them separately from the VOB as SRT or VTT files using a dedicated subtitle extraction tool.

Technical Notes

VOB files present a few unique technical challenges when converting to WEBA. First, VOBs often contain multiple audio streams — commonly AC3 at 192k, 224k, or 448k — and FFmpeg will select the default stream unless explicitly mapped. The -vn flag is essential here because without it, FFmpeg would attempt to encode the MPEG-2 video stream as well, which would fail since the WEBA/WebM container is audio-only and libopus only handles audio. The AC3 to Opus transcode requires full decode-and-reencode — there is no codec copy path available. DVD subpicture subtitles in VOBs are bitmap-based (not text), which means they cannot be remuxed into any container that doesn't support them, and WEBA doesn't support subtitles at all. Chapter data and DVD menu structures present in VOB files are also completely discarded. One practical concern with multi-part DVD VOBs (e.g., VTS_01_1.vob through VTS_01_6.vob): these represent segments of a single DVD title, and processing them individually will produce separate fragmented audio files rather than one continuous track. To handle this correctly on the command line, use FFmpeg's concat demuxer or the input format concat protocol to join them before conversion.

Related Tools

Convert VOB to 3GP Convert VOB to FLV Convert VOB to DVR Convert SWF to WEBA Convert AC3 to WEBA Convert WebM to WEBA Compress VOB Extract Audio VOB to MP3