Exploring and Idea, Accept camera input add graphic overlay, output to a specific HDMI port? Can It Be done With OpenCV?

1

Exploring and Idea, Accept camera input add graphic overlay, output to a specific HDMI port? Can It Be done With OpenCV?

Scenario, we have a camera output via HDMI, that is a clear feed, but we would like to add a graphic overlay depending on 3 different scenarios, and output the merged video and graphic to a specific HDMI port. Would like to do this via python on a Raspberry Pi 4 or 5. The video input is via HDMI to USB dongle, and the output via HDMI-A-2, i.e. the 2nd HDMI port of the Pi device.

I have researched if this would be possible using say, FFMPEG, but thought maybe using OpenCV would be a better scenario? Completely new to OpenCV, so seeking advice on if this is doable, and maybe if some has already done this, suggest an example of how it is done?

2

you don’t need OpenCV for that.

you just need to pop up a GUI for the display, and then use V4L2 to read from the video device, and draw your overlay (with the GUI toolkit).

3

Well I cannot use GUI system per se, It is HDMI in (via USB) and HDMI out of course.

I need to capture the input video, composite and then send it out the 2nd HDMI port that will be routed to a video hub, and from their routed to various devices.

I will look at V4L2 in depth. I used it a bit for configuration on different project where I had HDMI converting into a Rasberry Pi CSI port. But I barely scratch the surface using V4L2 just enough to set the input resolution.

4

but no GUI? why not? you have a (HDMI) video output. what else is that good for, if not displaying graphics… with a normal linux graphics subsystem?

you can cheat for now and just use OpenCV’s VideoCapture class to read frames from your video input.

5

Actually I got my HDMI to CSI interface board to see a connected camera using V4L2. And I got gstreamer to record video.

Odd that was not able to get OBS working with the camera/HDMI to CSI interface. But I know the camera and board work at a basic level I came over to how I can apply graphic overlay and then route the result to the desired HDMI port.