VOB Compressor

Compress VOB Files Online

VOB is the DVD-Video container, and a ripped disc is bulky — DVD-Video runs MPEG-2 at up to roughly 9.8 Mbps, so a feature film fills several 1 GiB .vob chunks. This tool re-encodes those files to a smaller .vob you can shrink by target size, bitrate, or quality preset while keeping the output DVD-compatible. One honest caveat up front: VOB uses MPEG-2, an old and inefficient codec, so if your goal is the smallest possible file rather than staying disc-playable, converting VOB to MP4 will save far more at the same quality.

How to Compress a VOB File

1. Upload Your VOB Files: Drag and drop the .vob files from your DVD's VIDEO_TS folder, or click "Add Files". A title split into VTS_01_1.VOB, VTS_01_2.VOB, and so on can be queued together — each file is processed in parallel.
2. Pick a Compression Mode: "Target file size (%) (Best)" scales the whole file to a percentage of the original (the default aims for 80%); "Specific file size" caps output at an exact MB figure; "Constant Bitrate" and "Variable Bitrate" give predictable or size-efficient results; "Constant Quality" (CRF) fixes perceptual quality and lets the size fall where it lands.
3. Set Resolution or Trim (Optional): Under Video resolution, keep the DVD's native 720×480 (NTSC) or 720×576 (PAL) frame, drop to a lower Preset Resolution for a smaller file, or set a custom Width × Height. Under Trim, choose Time Range to cut menus, trailers, or dead air before encoding.
4. Compress and Download: Click Compress. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up, no watermark, never shared.

VOB Compression Controls, Explained

Should You Compress the VOB or Convert It to MP4?

Compressing keeps the file as a .vob with MPEG-2 video and MP2 or AC-3 audio, so it stays playable on DVD players, VLC, and DVD-authoring tools. The limitation is the codec: MPEG-2 (H.262) dates to the mid-1990s and is roughly half as efficient as H.264, so re-encoding VOB-to-VOB shows blocking artifacts sooner as you push the bitrate down. If you only need the video to play on phones, browsers, and modern TVs, converting VOB to MP4 re-encodes to H.264 and typically produces a much smaller file at the same perceived quality. Keep it a VOB only when disc compatibility actually matters. If you do stay with .vob but want to preserve the original surround track, the advanced Audio Codec dropdown lets you hold the audio at AC-3 (Dolby Digital) instead of the MP2 default.

Frequently Asked Questions

Does the compressed file stay a playable .vob?

Yes. The output keeps the .vob extension with MPEG-2 (H.262) video and MP2 or AC-3 (Dolby Digital) audio — the same codecs a DVD uses — so it plays in VLC and works with DVD-authoring software. If you don't need that disc compatibility, converting to MP4 gives you a smaller, far more portable file.

How much smaller can I make a VOB file?

It depends heavily on whether you keep it a VOB. Staying in MPEG-2 typically gets you a modest reduction — often to around half or two-thirds of the original — before compression artifacts become visible, because MPEG-2 is an inefficient codec. In our testing, a 30-minute NTSC DVD title occupying about 2 GB across its VOB chunks re-encoded to roughly 1.1–1.3 GB as a compressed .vob at the Medium preset, but only about 350–450 MB when converted to an H.264 MP4 at similar perceived quality.

Why isn't my VOB getting much smaller?

You're re-encoding within MPEG-2, which was designed in the 1990s and can't compress as tightly as modern codecs. Two levers help most: drop the Video resolution below the native 720×480/720×576, and lower the Quality Preset. But the biggest single win is switching codecs — H.264 needs roughly half the bitrate of MPEG-2 for the same quality, so converting to MP4 often halves the file again on top of whatever the compressor achieves.

Will compressing a VOB reduce quality?

Yes, this is a lossy re-encode, so some quality is always given up. DVD video is already standard definition (720×480 NTSC or 720×576 PAL, interlaced), so it has little detail to spare, and MPEG-2 shows blocky artifacts sooner than newer codecs when you push the bitrate down. Use the Quality Preset or "Specific file size" mode to control the trade-off, and preview before committing to a very small target.

Can I compress several VOB files from one DVD at once?

Yes. A DVD splits a single title into 1 GiB chunks (VTS_01_1.VOB, VTS_01_2.VOB, …) purely for file-system compatibility, so upload the whole VTS_01_* set together and each file is compressed in parallel. If your real goal is to stitch those chunks into one continuous video rather than shrink them individually, the VOB converter joins them in order during conversion.

Should I lower the resolution or the bitrate to shrink a VOB?

Both reduce size, but they trade differently. Lowering the bitrate or Quality Preset keeps the full SD frame but introduces MPEG-2 blocking sooner as you push it down. Downscaling the resolution removes pixels outright, which can look cleaner at aggressive size targets because each remaining pixel keeps more bits. DVD content is already only 720×480 or 720×576, so going much below that rarely looks good — try the bitrate and quality controls first, then downscale only if you still need a smaller file.

Why won't my commercial DVD's VOB files compress?

Retail DVDs are usually scrambled with CSS (Content Scramble System) copy protection, and an encrypted VOB can't be read as ordinary video until it has been decrypted. This tool processes the MPEG-2 video stream, not DRM, so it works on home-recorded discs, camcorder DVDs, and personal rips that are already unencrypted — not on a still-scrambled commercial disc. Whether you may decrypt a given disc is governed by copyright and your local laws.

Should I trim before compressing, or compress the whole file?

Trimming first is almost always better when you don't need the entire title. Removing DVD menus, studio logos, trailers, or dead air before encoding means those seconds never get re-compressed, so the output is smaller and the compressor can spend its bitrate on the footage you keep. Use the Trim control's Time Range option, or the dedicated Video Cutter if you need frame-accurate cuts.

Is there a file size limit for compressing VOB?

There's no fixed per-file cap. Compression runs on our servers, so the practical limit is your upload size and connection speed rather than any hard ceiling — multi-gigabyte DVD rips are routine. If you need to hit an exact output size, use the "Specific file size" mode; to reduce a large rip much further, convert it to MP4 so the footage lands in the more efficient H.264 codec.