jittery motion with trackers

[carolina]

I always have the same problem when I am working with trackers: there is a slight jittery movement in the object which I have tracked. No matter the good my reference is, or the tolerance I choose, the jitter is there. My footages are PAL video (BCT-D) and I think if the interlaced is the responsible of this. I choose “Upper first” in the field separation of the footage controls and again when I make renders. Could anybody tell me what is happening and how can I avoid this jittery movement?

For example, if I want to put a picture on a white wall where the is a black point and the camera is making a pan, I would have a good reference and I could get a good tracker, but the result is that although the picture goes on the general movent of the camera, it is shaking! so nobody believe that the picture was there when the shot was recorded.

I hope somebody could help me. Thanks in advance.

Carolina.

Carolina.

[postist]

Have you tried de-interlazing the footage first? Are you tracking it while using “Best” view mode? Is the footage Digi-beta shot?

[Kurt Judson]

Thanks for replying so fast.
Yes, I work in the “best”mode, the shot is Digital Betacam, I digitalize it without compression and I’ve tried to deinterlace the footage, to apply the tracker and to interlace again and the result is the same: the jittery movement is there.
I had pointed that the possibility of the problem could be the interlaced PAL, but it was only an idea. I suppose that a lot of people works with PAL video so I wonder how can they get a correct tracker?
I’ve read that the tracker of Combustion is very good and it has the same basis as Flame’s tracker, but I’ve have seen a few ones and even the tracker reference was worse than the one I chose in Combustion, the final movement was perfect.
I’m eager to read more solutions. Thanks.
Carolina.

[postist]

It’s of course a bit trickey to say without seeing the source, Is the jitter field based or does it look like the tracked picture is moving independenly from the BG?

If the jitter looks like a filed error, you could try finishing the pice deinterlazed, IE dont reinterlaze your footage? Filed jitter can also ocur if there are different settings under footage control and composite settings. [/img]

[Kurt Judson]

The tracked picture follows the camera movement, but it has very little extra movement in all directions, as it was shivering with fever. As I said before the result is that nobody could believe the picture was there when the shot was recorded.
The field settings under footage control and composite settings are the same: upper (PAL)

😯

[bnw]

If you’re tracking fairly smooth moves, pans and dollies so on, you could smooth the curves afterwards, in the timeline.

[Kurt Judson]

Every frame has a keyframe, so in order to smooth the curves I can use “average”math operation in the timeline, but it doesn’t make the jittery movement disappear. I need that the tracked picture remains “nailed” to the background footage, following the camera movement.

[Faviel Ferrada]

If the shiver is caused by noise, you could try de-graining the footage a little.
or try resizing the tracking area, picking other tracking point …

shivering could also be caused by blurry tracking point, maybe some sharpening/contrasting could help

[greek]

hi,

you could try & vary the size of the reference a bit, if its bigger, that it tends to average the jittering.
probably you have tried already fixedroaming

another issue might be if you have different sharpness on front & back, this will result in a swimming impression ….

ciao
robert

[Anonymous]

Try adjust the keyframes manually or use the the average function like loops say. You can try stabilize the footage, and track the image after this you can “destabilize” the footage.

[Kurt Judson]

Thanks for your reply, Vympel, but as I told you before I have already try smoothing the movement curves with the “average” function, but it doesn’t work. Stabilizing – tracking – destabilizing the footage doesn’t work either.
Robc, thanks for your suggestion, but I think that varying the size of the refence isn’t the solution, because the problem of the jittering is always there, whatever the original movie was (always PAL video, of course).
I’m going to try degraining the footage a little, as Einstein has suggested (thanks). I’ll told you the result in two days, when I come back to my job.

Carolina.

[Nadim Shartouny]

Check that your tracking preferences are correct:

Tolerence set to 100%
Reference to ‘Fixed’ (if that is what you want)
Axis set to X&Y etc….

[Kurt Judson]

I’ve try contrasting or degrainning the background footage but this doesn’t work either.
Myth, of course I have already tryed to change the reference, the size, roaming-fixed, the tolerance, auto snap, smoothing curves, smoothin the background…
Nobody else has the need to get an very exact tracker as if the object where glued to the background?
Carolina.

[Anonymous]

carolina wrote:

I’ve try contrasting or degrainning the background footage but this doesn’t work either.
Myth, of course I have already tryed to change the reference, the size, roaming-fixed, the tolerance, auto snap, smoothing curves, smoothin the background…
Nobody else has the need to get an very exact tracker as if the object where glued to the background?
Carolina.

/

it can be useful you post a small part of the footage

[guillem ramisa]

Vympel wrote:

carolina wrote:

I’ve try contrasting or degrainning the background footage but this doesn’t work either.
Myth, of course I have already tryed to change the reference, the size, roaming-fixed, the tolerance, auto snap, smoothing curves, smoothin the background…
Nobody else has the need to get an very exact tracker as if the object where glued to the background?
Carolina.

/

it can be useful you post a small part of the footage

actually combustions tracker isn’t escpecially good. can you get somebody to track your footage in another app? like flame or mokey. they are rock solid.

[Author]

Posts