Wednesday, March 24, 2010

[Avid-L2] Re: Motion tracking Now Tracking Data not very accurate

The Avid tracker isn't that great. That said, tracking is an art and the more experience you have with it, the better you get. I've learned a lot of tricks to getting the Avid tracker to do what I need. But it ain't the AutoScrete tracker...

--- In Avid-L2@yahoogroups.com, "johnrobmoore" <bigfish@...> wrote:
>
> Played around with this and got it to work but the background has to be resized larger than the frame to accommodate the foreground moves which can get pretty nasty looking pretty quick. If there is a lot of pushing in and out on the foreground object the background is going to get noisy. What I found most interesting is how inaccurate the tracker is with a very simple tracking object. I know the Avid tracker has never been great but I thought with the addition of the DS correlation tracker it was supposed to be better than before. I made a simple title tool with a box like a TV screen and put 4 white dots over red in the box near the four corners of the box. I then promoted the title to 3D and moved it from the top left corner to the center of the screen increasing the size and then shrinking back to the bottom right corner. I made a video mix down and then tracked that. The correlation tracker would consistently move from the top edge of the dots and drift vertically under the dots over the course of the 10 second move. The fluid tracker was more accurate but still drifted off during the move. I tried moving the initial tracking point to the top center edge of the dot and also centered on the dot. In all cases the correlation tracker moved down. Perhaps the nature of my solid color simple source makes it more difficult although it seems like it would be easier than actual video to me. I have notice the last 6 or 7 months that trying to 4 point corner pin track has been less accurate than I think it use to be. I find I use to be able to track 4 points of a license plate and it would hold pretty well but lately the geometry seems to get overly skewed and the result is a very misshaped blur at the end of the track. This is with tracking points that seem to be holding and tracking the motion correctly. This behavior seems worse than it use to be. I can't give an exact version or time when this changed for me but definitely on Mac SNDX 3.5.4 I've pretty much given up on more than two tracking points and I use to use 4 in the past. Did something change that would effect this? I should add the tests I did tonight were on my MBP MCSoft 4.0.5.1 in SD 1:1.
>
> --- In Avid-L2@yahoogroups.com, "Terence Curren" <tcurren@> wrote:
> >
> > If that is what he wants, he drops a symphony warp (or resize then promote to 3D) on the top shot. Track the motion. Then drop that effect on the bottom shot and remove it from the top.
> >
> > Or, if he has already applied a key to the top, use the tracker and track the top. Then select the tracks in the tracker panel and CTL+C (copy). Turn off the tracker in the key. Apply the Symphony warp to the bottom track, open the tracker panel and CTL+V (Paste) and the tracking data from the other effect will be there.
> >
> > Very simple either way.
> >
> > --- In Avid-L2@yahoogroups.com, "johnrobmoore" <bigfish@> wrote:
> > >
> > > Sounds like he wants the motion data from the foreground blue screen to effect the background image. Sounds a bit like years back when they came up with a way to control a channel of ADO with data from a camera head shooting a blue screen image. Like a virtual studio tracks the background as the subjects camera move and zooms in and out.
> > >
> > > --- In Avid-L2@yahoogroups.com, "Terence Curren" <tcurren@> wrote:
> > > >
> > > >
> > > > Not sure I'm following exactly. When you use the tracker, you can select whether it tracks the foreground or the background.
> > > >
> > > > Is that what you are asking?
> > > >
> > > > --- In Avid-L2@yahoogroups.com, "eyesplice5" <eyesplice5@> wrote:
> > > > >
> > > > > Editing on Nitris DX 3.5.9
> > > > >
> > > > > I have a blue screen shot with motion reference dots.
> > > > >
> > > > > Is there a way to track the foreground motion blue screen shot to a background plate?
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Ed Salier
> > > > >
> > > >
> > >
> >
>


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