System Configuration : Preferences : MIDI Preferences : Delay for External Devices Section

Delay for External Devices Section
These options only apply when a Delay Compensation Engine is selected in the Playback Engine and Delay Compensation is enabled in Pro Tools. These options are distinct from the hardware offsets available for hardware inserts in the I/O Setup.
MIDI Timecode
When selected, Pro Tools applies Delay Compensation to Pro Tools-generated MIDI Timecode (MTC). Enable this option when synchronizing video to Pro Tools using MTC.
MIDI Beat Clock
When selected, Pro Tools applies Delay Compensation to Pro Tools-generated MIDI Beat Clock.