I can't find the answer in online docs, or elsewhere. Would you know what the magenta colour means on the motion tracking timeline? There doesn't seem to e different amount of valid tracking markers, so no idea what this could mean, but it results in loose of track on frame 1393 (place where the magenta colour starts). Thanks.

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EDIT: One more image with another color following enter image description here


1 Answer 1


The blueish line means that the frames have been prefetched or cached to RAM. Prefetching will give you better performance and playback, at the expense of available RAM.

enter image description here

Uncached frames are being read and decoded directly from the disk file.

(Form the Blender Manual)

Prefetch P

Fills cache with frames. As many frames as fits into cache are load form the drive. This allows to fill in the cache as fast as possible when you really need to track something, but this keeps CPU and drive bandwidth idle if you’ve got Clip editor opened but not actually interacting with it.

It is therefore recommended that you prefetch (cache) all of the frames that you are going to be working with to RAM. To do this load the video file on to the movie clip editor and press P to prefetch (or you can simply play back the video once and it will be cached).

By default blender will only use 1GB of RAM to cache frames. You can change that number depending on the amount of memory on your system. To do that open the User prefences (Ctrl + Alt + U) and on the System tab you'll see the options for the prefetch and cache limits.

enter image description here

Dark purple starts where the tracking is not reliable and has larger errors

If you see red-magenta on the timeline that means that Some Data Failed to Reconstruct, which means that the tracker information is missing or not reliable enough to reconstruct the 3d scene.

Read: Some Data Failed to Reconstruct, Motion Tracking

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

  • $\begingroup$ thank you for answer. My cache limit is 8GB, so I don't think that is the issue. I have added one more image to the question where you can see "dark purple", but the middle part is magenta and it seems like it is a combination of prefetch and uncached, which confuses me. $\endgroup$
    – koubin
    Jun 7, 2019 at 11:51
  • $\begingroup$ Read the edited answer. $\endgroup$
    – user1853
    Jun 7, 2019 at 14:06
  • $\begingroup$ Also, when posting images don't crop so tight, the rest of the information on the screen contains information that might be useful for users to help you. $\endgroup$
    – user1853
    Jun 7, 2019 at 14:11

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