Sync and Video : Working with Video in Pro Tools : QuickTime Movies Support in Pro Tools : QuickTime Movie Playback Performance Options

QuickTime Movie Playback Performance Options
High Quality QuickTime Image
When the High Quality QuickTime Image (DV25 Only) option is enabled in the Operation Preferences page, Pro Tools decompresses both fields of each interlaced frame of QuickTime video. When viewing a QuickTime movie in the Pro Tools Video window, select this option to display the movie at the highest possible resolution. For interlaced video that was transcoded from a progressive source, enabling option provides a crisper image in the Pro Tools Video window. For true interlaced video, enabling this option provides a smoother and clearer image when viewing the video on a client monitor.
Deselecting this option can help improve performance if your system experiences problems playing back a session with QuickTime video (such as comb-like interlacing artifacts or flickering video when monitoring using an Avid Mojo SDI).