LTC chase and 9 pin discrepancy

[nobby]

When locking a HD VTR to protools using machine control and dropping in to record on pro tools, the audio is half a frame earlier on the timeline than dropping into record when pro tools is chasing LTC. Therefore there appears to be half a frame difference between 9 pin timecode and LTC!!

Which one is correct?

Pro tools 7.4.2 with all updates!

[hummerZ]

LTC is the winner. Serial timecode is unreliable.

[Postman]

That shouldn't happen if everything is genlocked properly. Is your reference the same frame rate as the video?What frame rate is the video? Do you have SyncIO or SyncIO-HD? Is your reference tri-level or black?

[Bob Brown]

What if your video reference format when you are having problems?

[nobby]

Originally Posted by Postman

That shouldn't happen if everything is genlocked properly. Is your reference the same frame rate as the video?What frame rate is the video? Do you have SyncIO or SyncIO-HD? Is your reference tri-level or black?

Everything is locked to house black. HDCAMSR is locked to SD ref at 625. Pictures are 25psf. Pro Tools is locked to same SD ref at 625 using SyncIO.

[Postman]

A 25psf tri level sync should eliminate the problem, but of course you cannot do that because you have a syncIO. I have the same problem here. Easiest to do what hummerz says, use LTC. That way there is no question about field dominance of the 50 field reference vs. 25 frame video. I don't know for sure, but I think the deck can be set for either even or odd field dominance. SyncIO cannot be, though. So, you might try setting the deck to the "other" setting, maybe that would fix it, I'm not really certain. Or, plan to upgrade to a SyncIO-HD and use tri-level references. Or for now, just use LTC for positional reference!

Bob B may have better knowledge about this so I defer to his wisdom.

[Craig F]

? which 9 pin port are you using