Icaros

This is a great program, and I honestly can't say enough good things about it. Not only is it free, but it also works extremely well. It comes already with a pretty wide selection of both Video and audio files, as well as has what I consider to be its most useful feature, which is if you come across any image files, video files, or audio files that it doesn't already have in its dictionary, you can click and drag it, drop it on top of an icon on the application, and it'll add it to its repertoire. And I mean it can do things outside of just only video file formats and audio file formats. As an example, if you drop a dot .psd onto that icon, it can read .psd files and make you thumbnails for it. So far, other than extremely Nico specialized image files, such as .cmo3 And PDF files, I haven't found many that it can't handle.Other than that, the only two things I would say about it that are not great is one, the program when going through whatever files you've selected for it to cover can be kind of slow, especially if the videos it's making thumbnails for are long, which you wouldn't imagine would affect it since it's just making a thumbnail for it, but it does. But the bigger issue is that if you do have a large number of thumbnails, not only can they take up a decent amount of space on your drive, I've had the thumbnail cache crash my file explorer three times. To be fair with that, it did so with over 10,000 thumbnails each time. So That's kind of more on me. I think if the maker of this application could maybe add a setting to just make it so thumbnails not used within a given amount of time are deleted, that would make it ideal because then you would Rin into the over-large files crashing programs much less frequently.

Supported extensions: AVI, FLV, M2TS, MKV, MOV, MP4, OGM, RMVB. This means the app isn't an alternative to DarkThumbs, which offers previews of EPUB, FB2, Kindle ebooks (AZW, AZW3, and KFX), CBZ, and CBR files. It's an add-on, but not an alternative.

It works not only thumbnail for video files, but also cover pic for audio files (ogg etc). Also you can view artist, album, length etc info in explorer for every audio type.