I've made a simple file that I believe shows the same issue as with the eyes in the bugreporters first post. It's a monkey inside a refractive sphere.

I think these new merged tasks are not actually duplicate of this one. See my comment in T64945

I think this report should be reopened and treated as a separate issue.

Tried latest buildbot build 66c1b23 and tracking is not working at all anymore. It gets stuck at 0% and if I try to quit blender it will stop responding.

Looks like the video filename changed when it got uploaded. (To underscores instead of space.)
If you use my blend file you probably need to rename the video to this: Ski - 8558.mp4

I'm seeing the same thing also on Windows 7 and Linux Mint on another computer. Blender 2.79 RC1 and earlier.

This task probably needs to be reopened because I tried the latest build today (blender-2.78-fee7f68-win64) and still see the same behavior when userpref.blend is not present. (Using windows 7 64-bit)

I can confirm the same issue happening on my computer. 2.72 32-bit seems to work but not 64-bit.

I would just like to make you aware that this bug is now also present in windows testbuild1 and 2.

I'm guessing that the original reporter might mean that pressing the play button in the timeline controls won't make the movie play in the clip editor.
I was confused by this behavior too at first and found out you have to click the "Playback" dropdown and check "Clip Editors" to make it work. Using the Alt+A shortcut while the mouse pointer is over the movie window will always make the movie play.

It crashed for me too, but I had to select and track all markers. I changed the markers to match keyframe and it did not crash. I also tried from scratch with only the video and when I set markers to match keyframe it worked fine but if I set markers to match to previous frame it would crash. The same thing happened on some other videos I tried but suddenly I could not reproduce it anymore and even Camera.blend worked fine every time, even if I restarted Blender. I restarted the computer and tried again and Camera.blend crashed first time I tracked it, but then it worked again and I could not reproduce it anymore until I restarted the computer again.

I tried the latest build from buildbot (blender-2.69-b096845, both 32 and 64 bit) and did some quick tests. Everything is working fine here. It doesn't crash anymore and the occasional freezing of the screen issue I mentioned earlier seems to have been fixed as well. Thanks.

I can confirm the same crash on my computer. It happens exactly as described in first post. I did some tests on different versions of blender, both 32-bit and 64-bit.