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I recorded a video of a speaker at a graduation ceremony using my tablet. The first half of the recording, I held the tablet in my hand so it's shaky and just terrible. I finally realized that I could capture the scene I wanted just fine by using the tablet's stand and placing it on the ground.

Throughout the entire video, the background never changes, the speaker is at a podium and it can act as a focal point...other than the speaker, there is no motion in the scene (other than audience heads in the foreground.

I tried to use After Effects Motion Warp but it looks horrid but it would work perfectly if I could select a "static background" from one frame and apply that throughout the rest of the video.

Is something like this possible?

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While it's fairly easy for it to figure out the camera position from the shot, it is not nearly as easy for it to identify subjects cleanly. In order to do what you are talking about, the subject would have to be identified and extracted from the background without any extra bits coming along.

Computer vision algorithms simply aren't that advanced yet and such work is always either done by rotoscoping (manually outlining the subject on each frame) or using a chroma or luma key backdrop that can be removed. Stabilization works by identifying straight lines and tracking them generally. The border fill in motion warp then works by attempting something similar to what you are talking about by looking at what appeared to be there in previous frames, but it doesn't really work all that well yet either as it is a new technology.

The same problems that prevent them figuring out accurately what was there in previous frames are what prevent separating the subject from the background (the ability to identify, with precise accuracy, the same object in one image to another. You would end up with a subject that hovered oddly on the background and had a ring of background around them and/or left bits of them behind if you tried it with current level of technology.

Using motion warp and applying a crop or bypassing the auto-crop and manually cropping and moving around the frame is probably your best bet. This is how I usually handle stabilization issues.

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  • I was trying to use motion warp with crop but it would not allow, saying it would have excessive cropping. I'm fine with a 480p video, but it won't even give me the option. – Michael Brown Aug 7 '13 at 15:13
  • @MikeBrown - what I'm saying is to do it without the auto-scale/auto-crop and then do it manually. Basically you end up with a video where the objects don't move, but the scene will move in and out of frame. You then have to manually set up keyframes for motion to keep the screen full of image. The auto-crop and auto-scale tend to waste far more of the image than actually has to be wasted if you take the time to do your own cropping and scaling on the stabilized video. – AJ Henderson♦ Aug 7 '13 at 15:21
  • Do you mean frame by frame cropping? or do you mean use the stabilizer then crop to the consistent area? I'm VERY new to this, the last I worked with Premiere was in 2000 converting VHS tapes to digital video. – Michael Brown Aug 7 '13 at 15:49
  • @MikeBrown - you have select a viewable area from the video that the video doesn't move out of and then you use keyframes to adjust it to keep the viewpoint within the original image. When you stabilize, the result is that the image subject stays still, but the image edges move around it. You have to keep a crop that is within the area for which you have image and do so by adjusting the scale of the stabilized layer and adjusting it's position (via keyframes) to make gentle, smooth movements that keep the image covering the entire area on screen. – AJ Henderson♦ Aug 7 '13 at 16:52
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Deshaker which is a filter that can be applied in Virtual Dub, could fix the original shaking some, on mostly default settings (where the background moves).

Dehaker also has many many settings possible, you could mask out areas , as long as the person moving was then larger than the masked out area, and you got the settings all correct, it might be able to fix some of that up for you.

In most situations of any EIS (electronic image stabilization) It is cropping up a smaller portion of the whole video, and the methods for filling in where there is no picture at all (borders) are not great.

I find that setting everything and testing by looking at the vectors, using a excessive ammount of smoothing, and then using only about 1/2 of what would completly fix it , works ok to make the pictures a little more viewable.

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