Windows Explorer’s ability to display a thumbnail for a file can be a very useful way to see what it contains. But this often fails to work properly with videos, where typically you’ll be left with some general icon representing the file type, or perhaps a black frame which tells you precisely nothing at all.
You may be able to at least partly resolve this problem by installing the appropriate codecs, and making sure they’re configured correctly. But if that’s not working for you, then it could be simpler to install Media Preview, which handles all the usual complications almost entirely automatically.
The program is powered by Libavcodec, which means it already understands all the main video formats: 3GP, AVI, FLV, MKV, MPEG 1/2/4, Ogg video, QuickTime, RealMedia, VOB, Windows Media, and assorted variations of each.
But for the most part, you don’t have to worry about any of these complexities. Install the correct version for your PC (32-bit and 64-bit options are available), reboot and your new video thumbnails ought to be visible right away.
There is actually more going on under the hood than you might think, though. The program understands that it can’t just grab the first frame from a video, for instance (it might easily be blank), or any other random point. Instead it applies some intelligence to the task, and tries to ensure that the thumbnail is a truly representative frame which you really might recognise as belonging to the source video.
And if you care about these low-level details then there’s an interesting Configuration dialog which you might like to explore. There are options relating to the file formats you’d like to support, system caching, performance, how the thumbnails are generated, and a whole lot more.
In the main, though, Media Preview is just a quick and easy way to get Explorer working as it should, and if your current video thumbnails are somewhat less than helpful then the program could provide a simple solution.