Cowon A3 display 'unsupported codec' when VOB file is played.

MKV is a video container format which may contain various video or audio codec. If the video or audio codec is not supported by Samsung, it will fail to play mkv files on Samsung.
To play unsupported MKV files, it is better to convert MKV to MP4 H.264 with the help of Avdshare Video Converter.

check if it has same version of the player... if it has, try to re install the player

I assume you mean VOB. I have not heard of a VOD file...

If you have gotten your hands on a VOB file somehow, chances are they have been copied/extracted from a DVD. VOB stands for DVD Video Object and is the core file of a DVD containing the actual movie data, an MPEG movie stream and the supported audio.
To play the VOB files, you need to have a DVD player that supports VOB format. However, if you have the Windows Media Player (version 12 or higher) or VLC Media Player, it is good enough to play the file. Note that you will see a prompt telling you that it is an unsupported format, don't worry about it and just play it anyways. It will play just fine.
If you want to obtain the VOB file from a DVD for some reason, just open the DVD in Windows Explorer instead of playing it through a media player. The VOB file would most likely be under the VIDEO_TS folder. Some other files that you will also see in the folder are IFO and BUP. The IFO files are the information files containing meta data about the DVD and instructions for the DVD player on how to handle the disc. The BUP file is simply a backup copy of IFO files.
If you want to convert VOB file to AVI or a similar format, aviNET is a great tool to do that

Install the codec pack ie K-Lite Mega Codec or K-Lite Codec Pack @ http://www.free-codecs.com/index.htm

and you should be able to play most of the audio/video formats.

Hope it helps.

Download the Videolan media player, it can play almost everything. Google VideoLan or VLC Media player for the download link.

Search freeware on Google and find an AVI codec file to download and install. Then reboot and try again.

Hi there,
I can play .vob files with a cool media player called VLC player, which plays everything I throw at it. I recommend you download it from here:

http://www.videolan.org/vlc/

and when you install it, set the File Associations to play everything with VLC, that'll let you double click on a .vob file and play it automatically.
VLC has a much lighter 'footprint' than Windows Media Player, or Nero or many DVD players,and has amazing codec-support already included.
If the .vob files are encrypted, then maybe that is slowing down your laptop, but that is not the only reason for this to happen.
If it still restarts automatically, you may have picked up malware from downloaded movies, and need to download Spybot and scan and immunize your hard drive. Spybot is completely free. Trust me, i don't like paying for things :)
It's also possible that you need to clean up your registry and your drive with a free program called ncleaner. you can find that here:
http://www.nkprods.com/ncleaner/

I suspect you will be successful with VLC player, though. Enjoy your movies :)

Chris

I cannot play stay along VOB files from hard drive using WMP11, but I can play them by anothers videoplayers (WinDVD e.t.c). I would like to play them using WMP11 for windows media center

As you may have heard, with the Xbox 360 Flash Fall 2006 System Update they are adding support for WMV video playback from new sources. Videos can be streamed from a PC running Windows Media Connect, Windows Media Player 11, or the new Zune client player, and can also be played from Optical Disc and most USB mass storage devices. For all these sources, only the WMV video file format and codecs are supported. How do I know if a video file will work on the Xbox 360? Currently only the Windows Media Video (WMV) file format and codecs are supported. If you have a file with a ?.wmv? extension, then the odds are pretty good that it will work. Technical details on the types of files we support can be found at the end of this post, but the easiest way to find out if a file will work or not is to just try it. Hopefully after you click play the video will show up on your display, but if the content is not supported you will simply get an ?Unplayable Content? message blade from the side of the screen and then be returned to the Video blade. How do I create videos that will play on my Xbox 360? Windows Movie Maker, a standard feature of Windows XPSP2, will output WMV video files compatible with the Xbox 360 console. Either use the default settings when you finish a movie and click ?Save to my computer,? or just make sure that the output video format you select shows the file type as ?Windows Media Video (WMV).? Videos will usually look best when they are closest to the original resolution that they were created with. Try to create video files at least 360 pixels high in vertical resolution in order to minimize content upscaling on the console. If you decide you want finer control of the output video file format, download a version of Windows Media Encoder (http://www.microsoft.com/windows/windowsmedia/) and then start encoding away. Optimal size and bitrate settings will vary depending on the source material you are encoding. As a general guideline though, 1.5 Mbps is a typical bitrate that should be suitable for most standard definition content, and 8 Mbps is a common bitrate for high definition content. Can I get more technical details about the kinds of files you support? WMV video files with the extension ?.wmv? are stored in a generic file container format known as ASF. ASF files can contain many different types of codecs within them. Xbox 360 supports most common WMV video codecs, as seen in the following chart: Supported Video Codecs: Name FourCC Windows Media Video 7 WMV1 Windows Media Video 8 WMV2 Windows Media Video 9 WMV3 Windows Media Video 9 Advanced Profile WVC1 There are some files with ?.wmv? extension that may play on a PC, but are unsupported on the Xbox 360 console. Windows Media Screen, Windows Media 9 Image (Photostory), and some older Microsoft codecs are unsupported, as seen in the following chart: Unsupported Codecs: Name FourCC Microsoft MPEG-4 Video Codec V3 MP43 Microsoft MPEG-4 Video Codec V2 MP42 Microsoft MPEG-4 Video Codec V1 MP41 Windows Media Screen V9 MSS2 Windows Media Screen V7 MSS1 Windows Media Video 9 Image WMVP Windows Media Video 9 Image v2 WVP2 ISO MPEG-4 Video V1 MP4S Anamorphic content with nonsquare pixels is currently unsupported on Xbox 360 console, and will be displayed as if the pixels were square. If you want to play such content on your console, it is recommended that you re-encode the content in a square pixel format.

.Vob files contain audio, video and subtitles all together.However, most MPEG-2-capable DVD players don't support subtitle tracks. I guess your DVD player is in the mentioned majority. That's why you can only play them in your computer drive.