I have recently changed PC's so had to install Plex. Everything went well and I can see my movie library barring any movies that are in the VOB format. Not sure what the issue is here and I cant see any obvious setting. I should say it sees the folder that contains the VOB file but comes back as empty. - from PlEX forum

VOB, the abbreviation of Video Object, is a media container format for DVD video. It can wrap up digital video, audio, subtitles, DVD menus, and navigation contents all together into a stream form. At present, Plex doesn't support the use of VOB or VIDEO_TS folders that have VOB files. And Plex doesn't support transcoding VOB files directly. If you want to play .vob files with Plex, you may have to convert VOB to any of Plex supported formats (MP4 format is recommended). If you have no idea about that, you can follow this simple tutorial to get the job done.

Fix Plex VOB Playback Error

Get An Easy-to-use Tool to Convert VOB to Plex Compatible Formats

Some users changed the file extension from .vob to .mp4 or .mkv, and it worked with Plex. However, we don't suggest users do so since the way always fails. If you have a video encoding tool installed on your computer, you can use it to convert VOB to MP4 for Plex. If not, you can try EaseFab Video Converter Ultimate, which is a dedicated VOB file transcoder for desktop. It allows you to convert VOB, Video_TS folder, ISO, BDMV, and protected DVDs/Blu-rays to Plex highly compatible MP4 format in HEVC, H.264 with fast encoding speed and zero quality loss.

Moreover, it excels at video conversion with support of virtually all mainstream formats, like HEVC MP4/MKV, H.264, MTS, AVI, WMV, MOV, FLV, 3GP and more. It also presets hundreds of device profiles enabling you to directly convert VOB to iPhone, iPad, Apple TV, Android, Windows Mobile, Xbox, PlayStation etc. You can easily adjust video parameters like resolution, frame rate, bit rate etc., trim video length, crop video frame size and more.

Tutorial: How to convert VOB media files for smooth playback via Plex

To begin with, you need to download and install the VOB to Plex converter on your PC or Mac according to your computer operating system. The guide below takes the Windows version for example.

Step 1. Launch EaseFab Video Converter Ultimate on your PC or Mac, click Add Video button to load your source VOB files. (Note: batch conversion is supported, so you can load more than one file to save time.)

Note: If your VOB files are in a VIDEO_TS folder folder, you can directly drag the whole VIDEO_TS folder directly to the program, or open the VIDEO_TS folder, and pick the VOB files one by one. There are various VOB files in VIDEO_TS folder including adverting and trailers mostly main video file with the name VTS_01_1.VOB. If not, select other big files in size.

load VOB files

Step 2. Select an output format accepted by Plex, such as MP4 (h.264+aac) from Common Video category in the Profile bar. There're 420+ preset profiles. MP4 H.264 is universally supported and you won't go wrong with the format.

select output format

Tech details for VOB to Plex MP4 conversion with best quality-size balance:

1. To get the best possible output quality and smallest file size, convert VOB to HEVC MP4. It has 50% smaller size at the same quality. But please make sure that your device or media player does support HEVC for playback.
2. The default setting works well. Of course, if you want to customize video and audio encoding settings, just click the Settings button to customize these settings.

Recommended settings:

1. You're not suggested to adjust the frame rate and aspect ratio, if not necessary.
2. Use the codec H.264 or H.265 and lower the bitrate to a lower level. For example, adjusting the original Normal quality to bitrates of around 1800-2000 is acceptable without noticeable pixellation.
3. Lower the resolution. DVD VOB videos are 720×480 (NTSC) and 720×540 (PAL). Adjust the resolution to 640×480 won't make any quality difference.

Note: Adjusting these variables have some effect on the re-encoded video quality. Remember the file size and video quality is based more on bitrate than resolution which means bitrate higher results in big file size, and lower visible quality loss.

Common MP4 Settings

Step 3. Click the Folder icon in the Output bar to specify a destination folder to save the transcoded file. Finally, click the big Convert butotn to start re-encoding your VOB video. The length of your VOB file and your computer performance can affect the time it takes to finish the process.

After the process is done, destination folder will pop up. Play the resulting MP4 files via Plex. There's no trouble any more.