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Pretorian
11-25-2004, 03:05 PM
Hi!

I'm trying to stabilize a video in After Effects but I can't get it right. I could stabilize it a little but it stills shake, very little, but shakes. Probably I'm taking a not very good point to calculate. Should I maximize the calculation area?

Any suggestion?



Thanks

Khalor
11-25-2004, 05:56 PM
Ok, you could increase the calculation area, but this will really spike up your rendering times. There are a few other things you can try first:

1) Increase the subpixel matching. This will increase rendering time, but make the stabilizer much more accurate.

2) Check you are using rotational stabilization as well as positional, because a handheld camera wobbles from side to side as well as up and down (Meaning you track 2 spots)

3) Try using other track options (RGB, Luminance, Saturation)

4) Pick better spots!

Pretorian
11-29-2004, 07:28 PM
Yeah, I tried all the options you said, maybe I'm not getting the right combination, and spot :) !

It got better, sure, but it stills shake. How can I choose a good spot? Should I correct color, brightness, etc... to get the spot better?

Wich is the best way to stabilize a video?


Thanks

Khalor
12-01-2004, 10:41 PM
Right, the spots can be tracked in 3 ways:

RGB: It's best to use this when the colours contrast on the RGB spectrum (eg red dots on a green background)

Luminance: Use this when tracking areas of contrasting light/dark, but are not constrasting colours (e.g dark brown on yellow)

Saturation: I generally try to avoid using this, except when tracking areas which are different shades of the same colour


Also, when your filming, attack markers if possible to areas that can be easily masked, especially if bluescreening. Either that, or use a tripod!

Hope this helps,
Khalor

Pretorian
12-02-2004, 02:32 AM
Thanks!

Like I said, I have tryed some of thouse options. I think I will try again with saturation and see what I get.

How do you choose your spots?

After the video is stabilized it takes out of the original position, as you know, right? To correct this, what do you do? Increase the scale size? If yes, how much?


Regards

Khalor
12-02-2004, 06:34 AM
Just increase the scale size enough so you don't see black areas when your footage moves around. It changes depending on how unstable your clip is.
Alternatively, you can downsize your comp size. Not the best way do do it though.

I personally put red markers (just red dots) on the bluescreen/greenscreen. If it's not a screen, I choose track areas that are isolated, not a repeditive pattern (eg track a door handle, not the door frame)

If it's really not working, you can manually move the tracker area when analysing the clip. Just hit stop and move the tracker to the area, then hit analyse again.

And again, make sure you are tracking 2 spots, for rotational as well as positional tracking

Pretorian
12-06-2004, 02:26 AM
Thanks man!!

I can't use markers and tripod because I received the video already this way :), so, I guess you know how people give you the movies and ask for miracles!

I followed your advices and the movie got better, but not exactly stabilized. I will continue to search another spot.

About the spot, I heard that it should be something like an "L" or a cross, is this right? You said that the best option is "saturation", but, do you think I should "correct" luminosity, light and color before stabilizing?


Regards

Khalor
12-06-2004, 04:47 AM
L shaped orientation markers can help, especially if the footage requires manual orientation. Otherwise, tracking 2 spots does the same thing
As for adjusting luminosity, light, colour, etc..., you will need to apply these changes, then nest the comp into another comp. Otherwise, it will track the original footage, not the adjusted one. (At least, that's how it is in AE 5.5, I'm not sure about other versions)
I hope it helps,
Khalor

Pretorian
12-07-2004, 01:52 AM
Hi!

I just got your reply here. I will try what you said and see how it works. So, I'll be back to say how things went out! :)



Regards

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