MX Player is one of the most popular video player on android. there are free and paid versions. Mx player plays almost all audios and videos.various codec are supported some devices do not need codec but some do and these are available on Play Store.
If some videos do not play n your device then there are custom codec too.which can be downloaded from xda website(not promoting) which support Dts and Ac3(Thanks for codec dev KTSAMY) you can install these by copying in internal memory and make path to the codec file.