Some frames in camera track won't track

Support Compositing and Post Processing
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1

I’m pretty new at Blender camera tracking (but not camera tracking in general). I have a fairly long clip I’m tracking (can’t show due to NDA) that should be a dream–it’s one guy walking around on a sidewalk with a tiled pavement pattern. He occludes the trackers some times, but there’s always plenty of meaty detail to grab. For most of it it works great–it’s 850 frames–but the first last few frames are presenting problems, even though there is no substantial difference in motion or what’s being shown. (There are no edits, it’s continuous from the surrounding frames, and the ground is still the most prominent feature.) It’s fine tracking frames 5 - 850, but going back to frame 4 it does a sudden jump even when the tracked point has barely moved.

I’m using perspective motion model.

I realize this might be hard to answer without seeing it, but if anyone know any sort of “gotcha” that I can look for it would be appreciated. 840 beautifully-tracked frames are useless if the first and last 5 don’t work.

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I don’t think it’s a frame that can be tracked.
You can ignore or cut off that frame.
You do not use the entire frame to set the frame of Solve.
※ A short frame of about five frames can also be manually tracked by markers.

This is an estimate, but you might think it’s a problem to use the video file as it is.
Usually, sequence frame images are used for stability.

I don’t remember seeing anything about the problem in the lecture videos.
I think most of them cut out some frames that are problematic.

3

Problem solved. I used location-model trackers instead of perspective. Whole thing worked much better.