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I'm trying to track a relatively simple scene, and I keep running into weird problems. I know that the scene is blurry and low quality with only imperfect trackers available, but I don't really care about getting the motion tracking perfect. I just need a rough approximation as this will only consist of a few seconds in the rest of a project I'm working on, and visual effects isn't the main purpose of it.

Anyway, the animation starts at frame 90 and ends at frame 205, but Blender keeps insisting on solving the track from frame 89-253... and then failing at that due to not enough tracks or something. I think part of the problem was that I accidentally tracked some of my tracks too far beyond the end of the animation (using Alt+Left Arrow). Also, the entire video is much longer than the duration of the animation. But I can't figure out how to get Blender to just track the frames I care about and not the entire animation where only a few trackers remain accidentally enabled. Also, I can't figure out how to quickly disable the trackers after the end of the animation without manually disabling each one by hand each frame.

How can I get Blender to track only frames 90-205, or what's causing the following error?

Error

Here's the Blender file and video: https://drive.google.com/drive/folders/1rtCEqRwtqzN0PqP68Zq1EJOrEjXoZ7ns?usp=sharing

EDIT

Checking the Solve -> Keyframe checkbox and/or setting Keyframe A and Keyframe B to the start and end of the clearest section of my footage doesn't help as I still get the same error with it seemingly trying to track points outside of the duration of the animation. Again, all I want is for the tracking to only solve frames 90-205, which are the start and end frames in the timeline. But the console keeps complaining that it doesn't have enough data to solve frames outside that range.

EDIT

I managed to get it working by trimming the video clip to only have the frames that I wanted to track and then retracked the scene. However, I would still be interested in finding a solution that didn't require trimming the clip.

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    $\begingroup$ Does this answer your question? How to pick good keyframes for motion tracking? $\endgroup$
    – susu
    Commented Jul 25, 2020 at 18:04
  • $\begingroup$ @susu I've tried both options, but I still get the same error. $\endgroup$
    – ElliotThomas
    Commented Jul 25, 2020 at 18:15
  • $\begingroup$ Read the link on the answer below. Tracking is only useful if it is done accurately. $\endgroup$
    – susu
    Commented Jul 25, 2020 at 18:17
  • $\begingroup$ @susu I've also read through that, and I can't find anything that helps. $\endgroup$
    – ElliotThomas
    Commented Jul 25, 2020 at 18:21
  • $\begingroup$ If you don't have at least 8 accurate trackers within a range of keyframes then you won't be able to reconstruct. The error on the trackers you show is way to high. Take your camera and make a video that moves smoother. $\endgroup$
    – susu
    Commented Jul 25, 2020 at 18:26

1 Answer 1

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Enable the keyframe box, and then set the range of keyframes you want to use for solving in the boxes below (keyframe A and Keyframe B).

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Blender will solve the frames it can solve, meaning the frames for which there is a reasonable amount of information to estimate placement in the 3d world (or a low error). The slected range is used to determine the camera intrinsics and placement. Blender will then try solve the whole shot as marked in the beginning and end frame of the scene, but using the information gathered in the marked section of the shot.

For more information on motion tracking read this post:

How can I get better results when doing camera motion tracking?

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