However, K-Lite Codec Pack only works in Windows system and there is not yet a Mac Version of this software. Its supported formats include AVI, WMV, MP4, MOV, MKV, FLV, MTS, 3GP and more so that you can play virtually any video files with it. It can play almost all the movies which you download from the internet. K-Lite Codec Pack is a free package of media player codecs.