My markers in the movie clip editor keep "moving" around - what gives? I'm trying to add motion tracks to a video I've imported. Here is what I have done so far:


Open a clip in the movie clip editor.
Click "Add Marker" and Ctrl +  to place a marker.


Press Alt + → to track the selected marker forward one frame.
On occasion, the marker would need to be manually adjusted. I would do this by clicking in the little preview in the properties panel and dragging the background until it lined up properly with the correct location.


I completed this for the duration of the clip I wanted to use.


This is where things started acting up. I clicked the lock button for the track (the icon next to the eye in the screenshot above) and assumed that everything would stay as it was.

Unfortunately this is not the case. As soon as I jumped back to the beginning and began playing the clip, the marker wasn't in the correct location for each of the frames. Even though I had lined it up perfectly for each frame before, some of the frames had the marker in the wrong place.

How come it moved? What am I doing wrong?

Details


Blender 2.69 r60995
Windows 8.1 64-bit
AMD Radeon HD 7560D




Update:

Here is a screenshot of what happens when I push ← and → to toggle between frames 13 and 14:



Notice that the markers are moving. They aren't supposed to be moving. Something is clearly not working correctly here.
The issue might be caused by inconsistent decoding of your particular video codec by Blender, resulting in variation in the frame sequence you move through on the timeline. My suggestion would be that you convert the video to a discrete image format, like a PNG or JPEG sequence. A typical way to convert video to an image sequence:

ffmpeg -i "MyVideo.mov" -an -f image2 "MyVideo%06d.png"