Stablilizing long sequences with WARP

[Ivan Myles]

Try applying the stabilizer in multiple, shorter sections. Manually reposition to match the start and end points between sections as required. Also, don’t crop with Warp Stabilizer; keep the full image and add a displacement curve to move the image around. This will allow you to minimize cropping.

An alternative to Warp Stabilizer is the Stabilize Motion effect in After Effects. It provides more control over the settings: you can change the tracking point at different points in the video, edit the stabilization keyframes, and manually set the scaling factor. Note, however, that Stabilize Motion always tries to hold the tracking point in place; you will need to add a motion curve to minimize scaling.

Stabilize Motion in After Effects can be much more involved than Warp Stabilizer. In addition, Stabilize Motion typically requires multiple iterations.

[Dan Sakols]

Thanks Ivan. Im not sure what you mean by a displacement curve. Most importantly, I don’t want to scale my image, and essentially zoom in. I have not played with AE, but if that is the way to go, then there is where I will look. Is there somethign I am overlooking with WARP? I don’t wnat a sudden gross camera move, set a large zoom factor for the rest of the clip. I would expect that I should be able to set a max scale threshold, beyond which WARP will not go. There is a Max scale threshold slider, but when I set that to the point I want, it ends up cropping the image. How useful is that? I would like to set a maximum displacement of say 107%, and get the best stabilization within that constraint. Is there a way I can do this?

thanks,
dan

[Ivan Myles]

You can prevent Warp Stabilizer from cropping by setting Borders > Framing to “Stabilize Only,” and then adjust scale manually using Additional Scale. With Smoothing down to 1%, though, your options are limited. Over how many frames is the stabilizer being applied? Does the clip include multiple shots, or is it one continuous shot?

I am using the term displacement curve to describe Position keyframes, typically with Bezier in/out points, that shift the image to reduce cropping. The following example is from After Effects, but it can be applied as a motion effect in Premiere Pro, also.

The chart on the bottom shows Anchor Point and Position curves in After Effects Motion Stabilizer. Red is horizontal and green is vertical. The jagged curves are the anchor points produced by Motion Stabilizer to steady the image. The thin lines with only a few keyframes are the Position curves that were added manually to reduce cropping.

[Dan Sakols]

Ivan,

Im stabilizing a 30 min sequence of many shots edited in FCP. So what I gather WARP is going to zoom in some factor to give room for the most radical single stabilizing excursion in the sequence. I guess, even if there were tripod shots in the sequence, they would get the same zoom factor too. So what you are doing is analyzing the stabilization excursions, and then applying some “clamping” (the thin lines) to limit the cropping or zoom. And the bezier function is to soften that “clamp” so you dont get artifacts from halting the attempt to stabilize further. Is this right? to learn how to set this up, are there any articles? Can this be done in Premiere, or do I need to get AE?

Sorry for all the questions, but you understand the problem I am trying to solve.

dan

[Ivan Myles]

Im stabilizing a 30 min sequence of many shots edited in FCP.

Are you applying Warp Stabilizer to the entire sequence as one 30 min clip? If so, that’s the root cause. Replace the single clip on your timeline with a series of shorter clips (one clip for each shot you want to stabilize). Applying Warp Stabilizer to each shot individually should solve the problem.

The following discussion can be ignored if the above action resolves the issue.

Can this be done in Premiere, or do I need to get AE?

Works in either application. This discussion assumes Warp Stabilizer in Premiere Pro.

So what I gather WARP is going to zoom in some factor to give room for the most radical single stabilizing excursion in the sequence. I guess, even if there were tripod shots in the sequence, they would get the same zoom factor too

Yes. That is one reason why Warp Stabilizer should be applied on a shot-by-shot basis. Another reason is that the smoothing algorithm becomes meaningless once the shot changes.

So what you are doing is analyzing the stabilization excursions, and then applying some “clamping” (the thin lines) to limit the cropping or zoom.

Yes. The technique animates the clip to constrain the most extreme shifts so that cropping/scaling can be smaller. Let’s say that the Stabilizer creates a right border (crop) of 120 pixels, but you don’t want the border to be greater than 80 pixels in order to keep a low scaling factor. Then at the most extreme point, create a Position keyframe that shifts the image 40 pixels to the right to make the border smaller. Repeat this process at the extreme points for all borders.

And the bezier function is to soften that “clamp” so you dont get artifacts from halting the attempt to stabilize further.

Bezier = Ease In / Ease Out. It makes a change in direction less noticeable. You are trying to avoid pong-style bounces when changing direction.

to learn how to set this up, are there any articles?

I am not aware of specific instructions regarding this technique; it is just an application of some simple concepts. Here is basic information from Adobe help:

Animation and keyframes
Motion: position, scale, and rotate a clip
Controlling effect changes using keyframe interpolation

[Dan Sakols]

Ivan,

I have been trying to stabilize a single 30min clip, so as you pointed out, that may be the problem. This giant clip was the result of editing I was doing in FCP, and then exported are ProRes, as a flatened media file. In the future I will editing in Premiere, so then it will be possible to apply WARP to the individual clips in the timeline. I gather then, that if I apply a smoothness setting across all the clips in the project, they will be analyzed separately, and the resulting zoom factor (or crop) will be unique to each clip. So that clip where there was alot of camera shake, will be zoomed in more than a clip that was very stable to start with. Am I getting this right? Also, can I apply WARP across multiple clips in one step?

Thanks for sharing your insights on this- this has been very helpful.

dan

[Ivan Myles]

Glad to help.

This giant clip was the result of editing I was doing in FCP, and then exported are ProRes, as a flatened media file. In the future I will editing in Premiere, so then it will be possible to apply WARP to the individual clips in the timeline.

Not to worry! Use the razor tool to cut the flat file into a series of clips. Alternatively, open the file in the Source Monitor, set in and out points for each shot, and drag the clips onto the timeline one at a time. Then apply Warp Stabilizer to each clip independently.

I gather then, that if I apply a smoothness setting across all the clips in the project, they will be analyzed separately, and the resulting zoom factor (or crop) will be unique to each clip. So that clip where there was alot of camera shake, will be zoomed in more than a clip that was very stable to start with. Am I getting this right?

Yes.

Also, can I apply WARP across multiple clips in one step?

Warp Stabilizer can be applied to a nested sequence. Create a new sequence with the clips you want to group, and then insert it into the main timeline. Apply Warp Stabilizer to the nested sequence and it will treat the embedded clips as a single clip.

That said, I don’t recommend doing this. To the best of my knowledge, Warp Stabilizer does not have scene detection. When the smoothing curve for one shot is carried-over to the next shot, the beginning of the next shot will get screwed up.

[Dan Sakols]

Ivan,

I want to try your suggestion about truncating the most extreme excursions by countering with keyframe motion in the opposite direction that WARP is moving the picture. In the effects control tab, under Motion, I don’t see the smoothing motion that WARP is generating, as you showed me in the picture in this thread. To you example of reducing a 120 pixel excursion, where do I see that excursion. the only thing I can see is if I stabilize without crop, then I can see how the picture is moved about by WARP, but nothing is quantized. In other words, its hard to find the peaks that I would need to compensate.

Im trying to stabilize a clip shot with an iPhone, and even at 1% smoothing, it crops to 130%… too much

[Ivan Myles]

Hi, Dan:

The above image shows the Stabilize Motion utility in After Effects; the plots are not available in Premiere Pro. My intent was to explain the concept.

Yes, you will need to stabilize without cropping. It is usually not that hard to visually identify where the peaks occur; I just zoom into one of the corners and scrub through the sequence to find the points where the borders are maximized. After completing one corner I repeat the process on the opposite corner.

Another method would be to overlay a title containing a target rectangle with dimensions that are inversely proportional to your desired scaling factor. For example, with 1920×1080 footage that you do not want to scale more than 107%, create a rectangle with dimensions (1920×1080)*(100/107)=(1794×1009). Set the rectangle to be either border only (no fill), or lower opacity of the fill area to below 50%. Scrub through the video and identify the points at which the crop border is too big.

Create Position keyframes at the points where the borders are largest. An easy way to spot these points is to identify when the motion changes direction. Once you find a maximum, use trial and error to determine new X and Y Position values that sufficiently decrease the black borders.