Khan Desktop uses a built-in video player based on Microsoft's DirectShow multimedia framework and the open source LAV Filters ( https://github.com/nevcairiel/lavfilters).
Note the LAV Filters will not be registered on your system, and are used by Khan Desktop only. They will not effect other DirectShow filters on your computer.
Previous versions of Khan Desktop used a built-in VLC Media player ( www.videolan.org).
That version is still available at SourceForge ( www.sourceforge.net/projects/khandesktop/).