The Audio/Video tab allows you to adjust audio and video settings such as sound quality, display size and full screen mode. The Streaming tab allows you to set streaming options for live streaming, such as buffering and connection speed. On the General tab you can set preferences for playback, recording and language.

This will open the QuickTime Preferences window, which contains seveal tabs with various settings.

To change QuickTime settings on Mac, open QuickTime Player, then choose Edit > Preferences > QuickTime Preferences. You can also set QuickTime Player as your default player for all types of files in System Preferences > General. This will make QuickTime Player your default player for all files with the same type. Check the “Always Open With” box and click “Open”. From the contextual menu that appears, choose “Open With” > Other, and select QuickTime Player from the list of available applications. To make QuickTime Player your default player on Mac, you will need to open the file you wish to play and then right-click it. Making QuickTime Player the Default Player on Mac

Quicktime movie