Are you trying to play a that is still giving you trouble even with these players? K-Lite Codec Pack Mac Alternatives - Elmedia Player
Elmedia is a robust alternative designed specifically for Mac users who encounter "file not supported" errors in QuickTime. k-lite codec pack download for mac os x
K-Lite is built on , a multimedia framework created by Microsoft specifically for Windows. macOS uses Core Media and AVFoundation , which are entirely different architectural foundations. Are you trying to play a that is