Why does point tracking gradually slow down?
If you track a point on a shot which is quite long and not saved in RAM the tracker gradually slows to a crawl. I recently needed to perform a face track on a 15 minute piece of footage. It's near realtime for the first 300 or so frames then it gets slower and slower until it's tracking around one frame a second. This seems completely illogical, why would it matter how long the footage is?
Karolina Szablewska commented
Still a problem in 2021.
Yeah I wish this was fixed, I had to can this project partly because of this issue.
I was using the same work around as you Kaczorefx, but rather than copy pasting the keyframes I just pasted all the layers into one comp. I then made an expression on nulls to get the tracking data from the first active layer below the null.
Here's the expression, this version gets the layer name, but it's easy to change it to point at a particular tracking property if you're comfortable with expressions:
I second it.
It's not point tracking though, just the mask face tracking.
Either use the tracker from Character animator, or at the very least fix the one in AE.
It gets slower over time.
I start tracking the shot with 4 maybe 5 frames per second, by the time I get to frame 1000 I'm already down to 3seconds per frame. That's 12 times slowdown in 1000 frames!!!!.
The actual number of tracked frames (keys) seams to matter.
The solution is to divide the clip into several layers and track different parts in different layers, so 0-1000 on layer 1, 1001-2000 on layer 2, 2001-3000 on layer 3.
Each layer holds only 1000 keys at max so it kinda works.
Then you have to copy paste the keys back to layer one which is also very slow, but takes a lot less time than finishing tracking all 3000 frames on layer 1 :/