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Has anyone been able to track camera motion going primarily forwards or backwards? It seems that whenever I try, Blender is unable to make any sense out of all the trackers going in all directions and gives me a crazy blue error line in the tracking graph editor and triple-digit solve error values, despite all the individual trackers having solve errors under 1; I've tracked many primarily side-to-side shots over the years, so I know how to do a good camera solve.

I'm just wondering if Blender's 3D tracker has no way of interpreting forward/backward motion, which sounds like a crazy idea, given that Blender is so good and that no one seems to have noticed such a huge chunk of tracking functionality to be missing; but at this point, after having failed to solve multiple such shots over the years (and actually seen no examples of other people doing it), I'm really starting to wonder.

If anyone can say that they have successfully done it, then I'll have my answer (namely, that it's not a weakness in Blender, but something I'm still not doing right, which I can maybe try getting some help on in another post).

EDIT:

Attached are the blend files for a couple of the shots I've attempted tracking over the years (that I've been able to find).

https://drive.google.com/file/d/1P4EOqos0YEDJkJnqh_Xsa4CcL2eU_XSY/view?usp=sharing

https://drive.google.com/file/d/1DZ0nhQDz_Nh0fraI2oXzY7AzF5u9TNIO/view?usp=sharing

christsdude
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  • Blue and red are not errors, just mark the direction of the tracker https://i.stack.imgur.com/xWYm3.png. – susu Jul 25 '20 at 22:03
  • https://blender.stackexchange.com/questions/185251/render-is-duplicating-random-frames-when-loaded-into-3d-tracker/185253#185253 and https://blender.stackexchange.com/questions/51732/movie-clip-editor-playback-problem/51733#51733 and https://blender.stackexchange.com/questions/35699/unable-to-identify-frame-for-cut-in-vse-bug/35858#35858 – susu Jul 25 '20 at 22:06
  • @susu The blue line I'm talking about is in the graph editor, where it uses green and red lines to show the amount of movement in each axis for every marker (addressed here in the blender manual: https://docs.blender.org/manual/en/latest/movie_clip/tracking/graph.html); after solving, a blue line will show up as well, indicating the average error amount for each frame. If the blue line has spikes (or is consistently high), it indicates a high error value. – christsdude Jul 25 '20 at 22:08
  • It is impossible to guess what you are doing wrong. Please add a link to the video in question. A very common mistake is using the wrong solve model for the type of camera motion on the original shot. Please read https://blender.stackexchange.com/questions/42329/how-can-i-get-better-results-when-doing-camera-motion-tracking/42332#42332 – susu Jul 25 '20 at 22:11
  • @susu I've edited the question with files attached. – christsdude Jul 25 '20 at 22:42
  • @susu It says they're packed – christsdude Jul 25 '20 at 22:54
  • You can't pack video into a blend file. Only still images (and no image sequences either) – susu Jul 25 '20 at 22:56
  • Let us continue this discussion in chat. – christsdude Jul 25 '20 at 23:04

1 Answers1

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Blender can track backwards and forward accurately with no problem. I've done it many times.

So there is your answer.

Most likely the issue is with the compression used on the video. Intraframe compression or image sequences works great. Video with long GOP does not and might lead to errors retrieving frames going backwards.

susu
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