Raspberry Pi 4b vs. Jetson Nano

Currently, the Pi has a faster processor, however wold the Jetson’s GPU make it a better choice for QPrompt’s animation in higher resolutions?

I cannot recommend the Jetson Nano anymore because Nvidia will not update their supported operating system beyond Ubuntu 18.04, which is soon to become obsolete, and QPrompt can barely be compiled to run on Ubuntu 20.04. You can run QPrompt on the Nano if you’re able to manually install the nano’s kernel on some other distribution, like Fedora, openSUSE or a newer Ubuntu. You also need to jump pins and use a dedicated 5v power adapter to unlock the boot loader. Once you get it working, performance is lower than Imaginary Teleprompter’s due to QPrompt’s higher CPU usage.

Compatibility issues aside, the Jetson nano is the smoothest low profile computer I’ve ever run Imaginary Teleprompter on!

Thank you for the input. In your opinion, is it possible for the performance to improve on RPi4/400 or will it take new hardware to accomplish that?

There isn’t much room for improvement for prompting on a single screen. QPrompt v1.1 improves performance in this regard by reducing the number of layers and surface area that need to be composed. Nevertheless, the new contrasted overlay takes more GPU resources, so the net benefit may be negative on a low end GPU when bars are enabled.

When it comes to screen projections, there’s plenty of room for improvement. Now, the ways this could be achieved are very time consuming and well beyond my current skills. At the bottom of this page is a small discussion in which another developer and I talk about the bugs in that prevent us from easily copying visuals between with QML. The alternative, which I try to explain in my answer to the question, is to dig into Qt’s source code to access the window’s drawings as a whole in a more efficient way. Doing it this way would copy the whole user interface, but it wouldn’t be a problem if the prompter were to be on a window separate from the editor.

Could you please explain how to disable these features, if possible?

There’s currently no option to disable the contrast effect, tho it could be added. What you can do is not use bars for the overlay, as that improves performance greatly.

Other performance improvements are:

  • Do not using QPrompt’s Screen projections, duplicate the image using dedicated hardware.
  • Reduce display’s resolution.
  • Set QPrompt’s Pointers to “Left Pointer”, “Right Pointer”, “Both pointers”, or “None”. Do not using any of the “Bar” options.
  • Disable countdown
  • Disable all timers
  • Do not set a background image
  • Keep opacity at 100

On Windows systems:

  • Enable “High Performance” modes for Windows and the graphics card (if available).
  • Go to: Control Panel > System > Advanced system settings > Performance Settings and select “Adjust for best performance” to turn off all fancy display options, leaving more GPU time to other programs.

On Linux systems:

  • Use Wayland instead of X11.
  • Use Qt based or lightweight desktop environment or window manager, such as KDE Plasma, LXQt, Sway, or Enlightenment.