Player Undf Why Does My VLC Player Can't Play Mkv Or Rmvb Files?

Why does my VLC Player can't play mkv or rmvb files? - player undf

When I play RMVB and MKV files, which reads:

VLC supports any audio or video, "UNDP". Unfortunately, there is no way to solve this problem.
No suitable decoder module:
VLC does not support audio or video format "RV40". Unfortunately, there is no way to solve this problem.

I read much of what VLC plays all types of files.