[UPDATE] KMPlayer 18.104.22.168October 11, 2019
KMPlayer is a audio/video player that supports a vast assortment of file formats, such as AVI, MKV, MPEG, OGM, MP4, ASF etc. without any additional codecs installed. In addition, it has complete VCD/DVD playback performance. Moreover, it is equipped to play with AVI files, or media files that are locked while still sharing or downloading.
Note: In earlier times this application managed open source components against the terms of their various licenses. The present status of this is uncertain.