VOB to Y4M Converter
FileFlip converts VOB to Y4M entirely inside your browser, using FFmpeg compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a VOB file to Y4M?#
- Drop your VOB file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to Y4M and the conversion starts on its own. FileFlip downloads 30.8 MB of WebAssembly the first time and nothing after that, then runs FFmpeg on your own machine.
- Save the Y4M file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting VOB to Y4M lose quality?#
Y4M is a lossless format, so nothing further is lost here, but nothing is recovered either. Whatever the VOB encoder already threw away is gone, and the Y4M file will usually be several times larger for exactly the same content.
Is it safe to convert VOB files online?#
Yes, because nothing is uploaded. FileFlip converts VOB files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What VOB to Y4M actually does to the file#
Converting VOB to Y4M runs on FFmpeg, downloads 30.8 MB of WebAssembly the first time and nothing after that, writes a lossless file that cannot recover what the source already discarded, and drops encoded streams.
| Engine | FFmpeg |
|---|---|
| Conversion path | One step: VOB → Y4M |
| Downloaded to your browser | 30.8 MB, once, then cached by your browser |
| Quality | Lossless output, but nothing is recovered |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Encoded streams | Dropped | The target format has nowhere to put it. |
What is a VOB file?#
A VOB file is an MPEG-2 program stream built to the DVD-Video specification, interleaving a disc's compressed video, audio, subtitles and menu navigation data into files split at roughly 1 GB apiece.
Leave a DVD's VOB files as they are if the disc itself, or an ISO image of it, still plays fine in DVD player software.
Convert VOB to MP4 to get one continuous file free of CSS encryption and DVD menu structure, watchable on any device without a DVD-capable player.
What is a Y4M file?#
A Y4M file holds YUV4MPEG2 data, raw uncompressed video frames in planar YCbCr with a short plain-text header, the format codec developers feed into encoders like x264, x265 and vpxenc so nothing but the codec under test touches the pixels.
Use Y4M when testing or comparing video encoders, where the point is to remove every other codec from the pipeline so the one under test is the only variable.
Convert Y4M to a compressed format like MP4 for anything other than encoder testing, since the raw size makes it impractical to store or share.
VOB to Y4M questions people ask#
What produces a VOB file?
VOB files come from DVD-Video discs, whether commercial movies or discs burned by DVD authoring software. Every disc that follows the DVD-Video specification stores its video, audio, subtitles, and menus inside VOB files in the VIDEO_TS folder.
Why won't my VOB file play?
A VOB copied straight off a commercial DVD is usually still wrapped in CSS encryption, which most general video players can't decrypt, so it fails silently or errors out. VLC includes CSS decryption support built in and plays most commercial VOBs directly.
Why is DVD video split into multiple VOB files?
The DVD-Video specification caps each VOB at roughly 1 GB so the files stay compatible with filesystems that couldn't handle anything larger, a limit that predates DVD itself. A single movie plays across several VOB files back to back with no visible break.
What should I convert VOB files to?
Convert VOB to MP4 to end up with one file, free of CSS encryption and the DVD's menu and chapter structure, that plays on phones, laptops, and streaming devices without needing DVD player software.