If you are having problems viewing certain specific video files in your usual player, you have some options: install a new and advanced player or new Mega Codec Pack from K-Lite.
With this package, you can forget about different video formats that are difficult to play in most regular players. You can choose between different options, from a basic version, going through standard, full and mega packs. They will vary in their content, each one including even more features than the previous one. In this case, we will talk about the Mega Codec Pack. A user-friendly solution for playing all your audio and movie files.
This piece of software will allow you to play most of the different video formats using your regular Media Player Classic, so you don't have to look for and install a new and more resource demanding player.
It supports playback of AVI, MKV, MP4, FLV, MPEG, MOV, TS, M2TS, WMV, RM, RMVB, OGM, WebM, MP3, FLAC, M4A, AAC, OGG, 3GP, AMR, APE, MKA, Opus, Wavpack, Musepack, DVD and Blu-ray (after decryption), and many more audio and video formats.
You can add subtitles and the codecs will display them perfectly. Starting from the Standard Pack, you can enjoy the Media Player Classic Home Cinema which, in my opinion, is one of the lightest and best players.
With the Advanced and the Mega Packs, you will be able to use AC3, Haali, LAV and many more. You will get better quality using these codecs in combination with MPC-HC than using more "sophisticated" players.