Sync and Video : Working with Video in Pro Tools : Playing QuickTime DV Video to an External Monitor Over FireWire : Compensating for Video Monitoring Delays

Compensating for Video Monitoring Delays
You can compensate for delays in the video output that may be introduced by external decoders and certain types of displays (such as projectors or plasma screens).
To compensate for delays caused by video monitoring devices:
1 Choose Setup > Video Sync Offset.
2 In the Set Video Sync Offset dialog, enter a value in the QuickTime Video Offset field or Windows Media Video Offset field that is appropriate to compensate for the delay caused by your video monitor chain.
The amount of delay introduced varies based on your system and the type of video peripheral you are using. When using an Avid peripheral with QuickTime, 18 quarter-frames is a good starting point, but you will need to verify the precise setting for your system. (Third-party devices are available to help you measure this delay.
 
Once this value is set, it should not need to be updated unless you change components in your video monitoring chain (such as projectors or plasma screens).