The buffering of preview video is very slow. In a similar compositing software after affects is not fps problem. I really want to use this program. What is the problem? Windows 10, dell 7567, latest nvidia drivers are instaled, core i7 2.80GHz, video: 1050ti, ram: 16gb. Thank you in advance! Video: https://youtu.be/CIAqyVfqmvo
In Preferences/GPU Rendering, check that the OpenGL Renderer is your card, and not the Mesa Software Renderer.
Also, please try with the latest snapshot.
Now the problem is not solved on Windows 10? ;( I have not tested in Linux yet, opengl is supplies by default, maybe compatibility is much better.
It is not a GPU problem. This is normal.
Natron does all the processing in floating-point. This takes time and memory. And random-access into an H264 file is not that easy, which is why if you plan to do serious compositing you should use a proper video codec for your inputs (or even individual frames).
One HD frame takes 4*4*1920*1080=33Megs in floating-point format.