Turning ON vsync is what you need to do for dealing with tearing issue, not off. That article is about performance issues (and I don't agree with it anyway).
European TV is not 100Hz frame rate, it is 25Hz or sometimes 50Hz (for progressive scan). Your TV running at 100Hz could potentially cause a stobing effect (unlikely) see if you can switch it back to 50/25Hz temporarily to be sure.
Certainly the mismatch between the frame rate that the video source is at, and the refresh rate of the mode you are using on the graphics chipset could cause judder (but not normally tearing, if vsync is turned on). You should check what refresh rate the screen mode is using - probably 60Hz, and see if you can modify a modeline to pick a 50Hz screen mode. Also, trying in less than 1080p to start with might be useful. Say 720p - these actions will reduce the workload on your graphics chipset and reduce the possibility of the strobing effect, both of which will have a positive effect on judder, but again, not usually on tearing.
What graphics chipset are you using, and can you confirm that the xorg.conf file states the nvidia driver (not nv or vesa) is being used. Review the Xorg.0.log file to confirm that there are no errors when it tries to select this driver.
But first up be clear on the effect you are getting - juddering/jerking is when the pans/zooms or fast moving objects do not appear to move smoothly, as if some frames were dropped. Tearing is completely different - you will get a horizontal line somewhere on the screen, during motion (particularly horizontal) where an image appears to be sheared sideways, so the image above that line is somewhat to the left or right of the remaining part of the same image below that line. Not by a long way, but enough to be noticeable. If your video is correctly vsync'd this should not happen at all, unless you are running in alphablended mode.
Finally, from the KDE desktop, run glxgears and expand the window to be large, then watch the output in the console you ran the tool from and note how many frames per second it is able to achieve. Without vsync, a decent card should get several hundreds or even thousands of fps, with vsync it should be exactly 50 or 60 fps. When vsync is on, also note whether there is tearing on the animated gears.