-
Tracking then trimming
I’ve been cutting a show with a lot of monitor burn ins going into plates shot hand held. They all need tracking and depending on the shot I’ve tried a variety of methods from Mocha to Boris to — most of the time — Avid’s own tracker. The project is still a work in progress, so it’s not unusual for me to track material into some of the monitors only to decide later I want to trim the shot. I get it that if I lengthen a tracked monitor shot, I’m going to have to re-track. But it seems that I’m not able to shorten a shot without losing the tracking. Is it the case that once a motion track has been created it always starts from the first frame of the cut even if I change that first frame? In other words am I correct that shortening a tracked shot will always throw the track off or is that dependent on the kind of tracker? I would have thought that if I shorten a shot, the track data would shorten in sync, but I must be wrong. Can anyone clarify? (BTW I just used the new feature in Mocha 2.6 that allows you to export tracking data to the Boris Corner Pin effect. I had a pretty complex track — a hand held and sped up pan across five of those cursed monitors with no more than two in frame at any one time. It was a long process to build all the Mocha tracks, but I could then import them into Avid via the Boris plug in and it worked wonderfully — until, of course, I decided I wanted the pan to start a little later and sure enough all my burn ins were floating in the frame — curses). Thanks for any insights.
-
3 Replies
-
2 possible ways to work around it:
If you put your previous shot onto a higher Video track, above the incoming tracked shot, and covered the incoming frames, the tracking information would not be changed, so the shot should work.
Second, nest the tracked shot, and try trimming that. (I haven’t tried that, but it could possible work).
Please let us know if that works. -
Another workaround, with a major caveat. Prior to tracking, make the shot/shots with the effect as long as you can anticipate it being. Extract a subsequence to go back to if you need to make changes again. Do your tracking and other work and create a mixdown and place that in your final working timeline using only what you believe you need at the time. You’ll have more of the created effect if you need to trim, but you won’t need to recreate the effect or the tracking data every time you trim. The major caveat being, is that if you are replacing the shot with uprezzed or color corrected video, or want to change the segment in any other way, you’ll have to go back to the subsequence, make the changes there, remake the mixdown etc.
M. Scott Cole
Senior Post Production Editor
60 MINUTES
CBS News, NYC
sc6@cbsnews.com
mscottc@comcast.net -
Thanks Juris and Scott. I really like Juris’ wedding cake idea — I usually don’t layer video unless it’s to create blends of some sort — but in this case that’s a clever way to work with my situation. I think I did try collapsing the clips but that didn’t seem to help. I also had used Scott’s idea of the video mixdown, but his caveat is correct especially since I don’t create the final effects. Mixing down is great for screening purposes but my poor assistant who has to pass counts on to the VFX house growls at me. What I’m understanding from both of you, however, is that my conclusion is correct that a track will always start on the first frame of a cut and not adjust itself to trimming. I gather you’d agree this is true of all trackers.
Stephen
Reply to this Discussion! Login or Sign Up