Operating system: Debian 10 (Buster)
Graphics card: intel integrated
Broken: 2.79.b+dfsg0-6+b1 (debian/buster package version)
Short description of error
Often while creating motion tracking points, random movie clip frames will become duplicated or skipped and random runs of frames in the video will become off-by-one (i.e. the currently displayed frame is actually the previous/future video frame). This phenomenon occurs randomly, but tends to occur around the beginning/end of individual runs of tracks.
This is made worse by the fact that the automatic tracker will track against the erroneous duplicate frames, causing the tracks themselves to contain consecutive vertices that are in the exact same location, and long runs of tracking points that are off-by-one frame. In my experience, this has made it exceedingly difficult to attain an acceptable solve error.
When I enable proxy clips, it tends to eliminate the frame display errors, but the automatic tracker seems to use the original erroneous frames rather than the displayed proxy frames. Interestingly, I can detect when the original clip is off-by-one frame by toggling the "Proxy/Timecode" checkbox.
It's unfortunately difficult to describe this bug, but here are other reports that I have found elsewhere on the internet:
Exact steps for others to reproduce the error
- Open a new blender project.
- Go to the Motion Tracking layout.
- Open any video.
- Add some tracks, use automatic tracking (i.e. Track Forwards/Backwards).
- Observe duplicate consecutive vertices in any track.