Frame rate question

What is the most reliable (accurate) method of determining the frame rate a composition is running at?
Related, is the Vuo window always locked to screen refresh or is there a way to create a window without vsync (old terminology, don’t know what the right term is now).

Most reliable is to look at the port popover for the trigger driving the rendering.

For a rate other than the refresh rate, you can use Fire Periodically. (The reason that the window nodes always fire at the refresh rate is to avoid screen tearing.)

So, if on the output of my movie node, “last event” says 30fps can I be confident that the the movie is not dropping frames?

But what I am really want to do is … I have written a GLSL shader that does some pretty heavy lifting. I want to see how it scales with the output resolution of the image it generates. Specifically if the updates on the window are dropping below the 30fps of the movie. Suggestions?

If the popover says it hasn’t dropped any events, then Vuo is submitting all movie frames to the macOS window server to be displayed. This doesn’t 100% guarantee that macOS won’t drop frames (that’s out of Vuo’s control), but it’s a pretty good indication that your system is keeping up with the movie framerate.

With a simple composition, just Play Movie → your shader → Render Image to Window, the port popover would be a good measure of the effect of output resolution on your shader.