Convert VOB to AVI — Free Online Tool
Convert VOB files from DVD discs into AVI format by re-encoding the MPEG-2 video stream to H.264 (libx264) and the AC3 audio to MP3 — producing a compact, widely playable file without the DVD-specific container overhead. Ideal for archiving DVD content into a format compatible with legacy media players, older smart TVs, and Windows-native software.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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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 contain MPEG-2 video and AC3 (Dolby Digital) audio multiplexed inside a DVD-Video container that also carries subtitle streams, navigation data, and sometimes multiple audio tracks. Converting to AVI requires full re-encoding of both streams: the MPEG-2 video is decoded and re-encoded to H.264 using libx264, which delivers significantly better compression at equivalent visual quality, and the AC3 audio is decoded and re-encoded to MP3 using the LAME encoder, since AVI's MP3 audio is the most broadly compatible audio option for that container. Subtitle streams and DVD menu data from the VOB are dropped entirely, as AVI has no native subtitle support. The result is a single self-contained AVI file with interleaved audio and video that plays on virtually any media player released in the last two decades.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg program. This is the same underlying engine that powers this browser-based tool via WebAssembly — so the command shown here will produce identical output if run locally on your desktop. |
-i input.vob
|
Specifies the input VOB file. FFmpeg automatically detects the DVD program stream container and identifies the MPEG-2 video and AC3 audio elementary streams multiplexed inside it. |
-c:v libx264
|
Re-encodes the MPEG-2 video stream from the VOB using the libx264 H.264 encoder, replacing the DVD's older compression format with one that achieves significantly better file size efficiency at equivalent visual quality. |
-c:a libmp3lame
|
Re-encodes the AC3 (Dolby Digital) audio from the VOB using the LAME MP3 encoder, converting it to MP3 — the most universally compatible audio format for AVI containers and legacy media players. |
-crf 23
|
Sets the Constant Rate Factor for H.264 encoding at 23, the libx264 default. This controls the quality-to-file-size tradeoff: lower values (e.g., 18) give higher quality and larger files, while higher values (e.g., 28) reduce file size with more visible compression. |
-b:a 128k
|
Sets the MP3 audio bitrate to 128 kbps. This is sufficient for stereo audio at standard DVD sample rates (48 kHz), though it represents a significant downgrade from the original AC3 which was often encoded at 192–448 kbps with surround channels. |
output.avi
|
Specifies the output filename with the .avi extension, which tells FFmpeg to mux the encoded H.264 video and MP3 audio into an Audio Video Interleave container with interleaved data blocks for broad playback compatibility. |
Common Use Cases
- Archiving ripped DVD content into a leaner H.264/AVI file that plays on older Windows PCs and media centers without installing additional codecs
- Preparing DVD footage for import into legacy video editing software such as older versions of Windows Movie Maker or Sony Vegas that handle AVI natively but struggle with VOB containers
- Converting home movie DVDs into AVI files for storage on external hard drives shared with family members who use basic media players without MPEG-2 decoder support
- Reducing the file size of large VOB files from DVD rips — H.264 typically achieves 40–60% smaller files than MPEG-2 at equivalent visual quality, saving storage on NAS devices
- Making DVD-sourced video compatible with older Android set-top boxes and media players that support AVI/MP3 but lack MPEG-2 or AC3 decoding capabilities
- Stripping DVD container complexity from VOB files when sharing clips with collaborators who need a simple, universally openable video file without DVD playback software
Frequently Asked Questions
Yes, some quality loss is unavoidable because both the video and audio streams must be fully re-encoded. The MPEG-2 video in the VOB is decoded and re-encoded to H.264, and the AC3 audio is decoded and re-encoded to MP3. However, at the default CRF 23 for video and 128k for audio, the perceptual quality loss compared to DVD-quality MPEG-2/AC3 is generally minimal for standard viewing. If you need higher fidelity, lower the CRF value (e.g., to 18) and raise the audio bitrate to 192k or 256k.
The AC3 audio — which on DVDs is often 5.1 surround sound — is decoded and re-encoded to stereo MP3 at 128k by default. This means the surround sound channels are downmixed to two channels, losing the discrete surround information. If preserving multi-channel audio is important, AVI is not an ideal target format; consider MKV instead, which can carry AC3 passthrough directly. For AVI output, increasing the MP3 bitrate to 320k can improve stereo quality but won't recover the lost surround channels.
No. VOB files can carry DVD subtitle streams (as bitmap-based image overlays), but AVI has no native subtitle track support, so all subtitle data is dropped during this conversion. If you need subtitles, you would need to either burn them into the video stream using FFmpeg's subtitle filter before conversion, or export to a format like MKV that supports embedded subtitle tracks.
You can concatenate multiple VOB files from the same DVD title using FFmpeg's concat demuxer or by using a glob input. The simplest approach is: create a text file listing each VOB (e.g., 'file VTS_01_1.VOB' on separate lines), then run: ffmpeg -f concat -safe 0 -i filelist.txt -c:v libx264 -c:a libmp3lame -crf 23 -b:a 128k output.avi. Alternatively, on Linux/macOS you can use: ffmpeg -i 'concat:VTS_01_1.VOB|VTS_01_2.VOB|VTS_01_3.VOB' -c:v libx264 -c:a libmp3lame -crf 23 -b:a 128k output.avi.
The -crf flag controls H.264 video quality on a scale from 0 (lossless) to 51 (worst). The default is 23, which is a good balance of file size and quality for DVD-source MPEG-2 content. To improve quality at the cost of a larger file, lower the value — for example, '-crf 18' produces near-transparent quality. To reduce file size further (accepting more compression), raise the value to 28 or higher. For DVD archiving where preserving the original visual fidelity matters, values between 18 and 22 are typically recommended.
This can happen when the CRF value is set low (high quality), because H.264 encoding at high quality settings can produce more data than the original MPEG-2 stream for certain types of content — particularly static scenes or video with fine grain where MPEG-2's older compression artifacts were masking detail. For typical DVD content at CRF 23, the AVI output is usually smaller. If file size is a concern and the output is unexpectedly large, try increasing the CRF to 25 or 28, or verify the source VOB isn't already a low-bitrate encode.
Technical Notes
VOB is a tightly constrained format rooted in the DVD-Video specification: video is limited to MPEG-2 at up to 9.8 Mbps, and audio is most commonly AC3 (Dolby Digital) at up to 448 kbps, with the container also carrying program stream navigation packs, private stream data, and bitmap subtitle packets. None of this DVD-specific metadata is meaningful outside a DVD playback context, and AVI has no mechanism to store it. The H.264 output produced by libx264 is substantially more efficient than MPEG-2 — for typical DVD content (interlaced 480i or 576i source), you can expect visually equivalent quality at roughly half the bitrate. One important consideration for interlaced DVD content: by default, this command does not apply deinterlacing, so if the source VOB contains interlaced video (common for TV recordings on DVD), the output AVI may exhibit combing artifacts during motion. Adding '-vf yadif' to the command before the output filename will deinterlace the video during encoding. AVI's use of the OpenDML extension is required for files exceeding 2GB, which FFmpeg handles automatically, but some very old players may not support this extension. Multiple audio track support exists in AVI but is rarely handled correctly by consumer playback software, so only the first or default audio track from the VOB is mapped by default.