Solve camera motion error: At least 8 common tracks on both of key frames are needed

I have 14 tracking points that all went trough the footage with no problem but I still get this error when I try to solve camera motion:

At least 8 common tracks on both of keyframes are needed for reconstruction

Any ideas why?

Never mind. I found the solution to the problem myself. :slight_smile:

That’s great. I’m really happy that you found the solution, but it would be nice if you told us what this solution was.
Let’s say someone is looking for the answer to the same question. When he finds your post - the only think he can learn is that you have a solution. :slight_smile:

Agreed!
I’m getting that error with Blender 2.64. I’m trying to do an object track. The object has 16 tracks, with about 10 that run continuously through the clip. However I am getting the ‘at least 8 common tracks’ error message!

Any help would be appreciated.

Thanks.

Sorry guys.

It was a silly mistake. I didn’t properly specified the amount of frames range so half of (second) key frames were left out. You need two of them for each tracker. Without them the camera can’t be solved.

@maffster: I usually pick one from problem making and do them manually. It is the best way to see where is the problem. If the scene is simple 10 tracks should be enough to solve your camera imho.

Thanks for the reponse!
I’ve sorted the problem now.
I was only tracking a portion of my clip and had specified a start of 150 and end of 500, but the Keyframe A was still set to 1 - so it was trying to solve a selection of the clip with no tracks at all!
Changing the Keyframe A to 150 sorted it out!


Regards,

Maff

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Guys still dont get it :stuck_out_tongue: can u tell what exactly i have to do?

In the Tracking solve settings you have keyframe A and keyframe B. You need at least 8 tracks that all span that keyframe range

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Sorry i cant understan what exactly means “You need at least 8 tracks that all span that keyframe range

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The Keyframe A/Keyframe B area specifies the range of keyframes that the tracker is analyzing in order to come up with a camera solve. In order for the solve to occur, you need 8 or more trackers that exist within the keyframe span that you defined; otherwise, no camera solve.

Coincidentally, that keyframe span should contain a LOT of parallax in order to get a good result. More markers+lots of parallax = low error rate.

Best of luck!

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great ,
thank you soo much for the fix.
i really appreciate.

Hello there. I am ilbailba. Thanks a lot for this comment. I will be able to use a better blender thanks to you. thank you so much.