Free online MK3D to VOB converter

DVD authoring software and standalone DVD players require video in the VOB structure, while MK3D is a Matroska container intended for stereoscopic video playback. Converting it is useful when creating a DVD, but standard DVD-Video cannot preserve most modern 3D formats.

What the MK3D format is

MK3D is the Matroska extension used for stereoscopic video, commonly containing H.264 or HEVC video, multichannel audio, subtitles, chapter data, and Matroska 3D metadata. The extension identifies the container; it does not identify a specific video codec.

You may encounter MK3D files after ripping or remuxing 3D Blu-ray content with software such as MakeMKV or MKVToolNix. VLC, MPC-HC, Kodi, and other Matroska-compatible players can usually open them, provided the contained codec and 3D layout are supported.

What the VOB format is

VOB is the container used inside a DVD-Video disc's VIDEO_TS folder. It stores MPEG-2 video, DVD-compatible audio such as AC-3 or MPEG audio, subtitles, navigation data, and related DVD title information.

VOB is appropriate for a disc that must play in a conventional DVD player. Its restrictions include a maximum video frame size of 720×480 for NTSC or 720×576 for PAL, DVD-compatible frame rates, MPEG-2 video, and limited audio formats. A standalone MPEG program stream with a .vob extension is not necessarily a valid navigable DVD title; DVD authoring must create the required navigation structure.

How to actually convert MK3D to VOB

For a desktop workflow, FFmpeg converts the MK3D video to DVD-compliant MPEG-2, and DVD author creates the actual VOB files.

1. Inspect the streams and determine whether the file contains a side-by-side, top-and-bottom, frame-sequential, or ordinary 2D video stream:
   ffprobe -hide_banner input.mk3d
2. Convert the selected video and audio to an NTSC DVD-compatible program stream. Use explicit stream mapping when the file contains multiple video or audio tracks:
   ffmpeg -i input.mk3d -map 0:v:0 -map 0:a:0 -target ntsc-dvd -aspect 16:9 -c:a ac3 -b:a 192k dvd.mpg
   For PAL output, replace ntsc-dvd with pal-dvd. Use -aspect 4:3 when the source is standard 4:3.
3. Author the MPEG stream with dvdauthor:
   dvdauthor -o dvd -t dvd.mpg
dvdauthor -o dvd -T
4. Use the generated file dvd/VIDEO_TS/VTS_01_1.VOB as the authored VOB. Additional VOB segments may be created automatically when the title exceeds the DVD segment-size limit.

If you only need a quick conversion and do not need to author a playable DVD, you can use the free converter on 101convert.com without installing software. Its result may be a VOB-compatible MPEG program stream rather than a complete DVD-Video folder, so test it with the intended player.

Quality, compatibility, and limitations

DVD-Video requires a new MPEG-2 encode when the MK3D stream uses H.264 or HEVC, so quality decreases and the output file is constrained by DVD resolution and bitrate. The FFmpeg -target preset handles the main DVD video parameters, but the source frame rate must still match the selected NTSC or PAL standard.

DVD-Video does not preserve Blu-ray 3D frame packing or most Matroska stereoscopic metadata. A side-by-side or top-and-bottom source can be encoded as a normal 2D frame containing both views, but a standard DVD player will not automatically reproduce it as hardware stereoscopic 3D. For genuine 3D playback, retain the MK3D file or use a 3D-capable Blu-ray or media-player format.

Basic stream mapping transfers only the selected video and audio. Chapters, multiple audio tracks, Matroska subtitles, and 3D flags require separate DVD authoring steps; Matroska subtitle formats generally must be converted to DVD subtitle assets before authoring.