Can't use multiple cameras on Ubuntu 20.04

[frnsys]

Hi, thanks for all your work on this project. I'm excited to see where it goes.

I'm having an issue where I can't seem to get this working with multiple cameras. I have three webcams plugged directly into my laptop (I also tried plugging into a hub, but didn't change anything).

When I go through the camera setup process and click "Submit", only the first camera lights up and only a blank rectangular window appears.

This is the output I see:

__________________________________________
cv2::videocapture properties for Camera# 0
CV_CAP_PROP_FRAME_WIDTH: '640.0'
CV_CAP_PROP_FRAME_HEIGHT : '480.0'
CAP_PROP_FPS : '30.0'
CAP_PROP_EXPOSURE : '0.008200820082008202'
CAP_PROP_POS_MSEC : '0.0'
CAP_PROP_FRAME_COUNT  : '-1.0'
CAP_PROP_BRIGHTNESS : '0.5019607843137255'
CAP_PROP_CONTRAST : '0.12549019607843137'
CAP_PROP_SATURATION : '0.12549019607843137'
CAP_PROP_HUE : '-1.0'
CAP_PROP_GAIN  : '0.20392156862745098'
CAP_PROP_CONVERT_RGB : '1.0'
__________________________________________

It looks like it's getting stuck on the first camera and never manages to start up the other cameras?

It works fine if I select just one camera.

[frnsys]

I looked into this and the camera setup/recording threads were blocking each other. I switched to using multiprocessing instead and that seems to work.

I had to make a few other small changes to get things working; they're all in this commit: frnsys@3036555

I realize though those changes might not be relevant as you're refactoring the code anyways, but hopefully it's helpful to someone :)

[HitLyn]

Many thanks for sharing the solution. I have the same problem here. Why not create a pull request? I guess this should be a common problem for all ubuntu 20.04 users.

[jonmatthis]

Great thought, but not the right time :)

We've frozen development on the pre-alpha version of the code at v0.0.54, so we aren't in a position to incorporate the PR

We're getting UNBEARABLY CLOSE to release of the new alpha version of this software which will include a full GUI based controller will be cross-platform compatible.

Thanks for the interest and the work! Stay tuned :D

[HitLyn]

Great thought, but not the right time :)

We've frozen development on the pre-alpha version of the code at v0.0.54, so we aren't in a position to incorporate the PR

We're getting UNBEARABLY CLOSE to release of the new alpha version of this software which will include a full GUI based controller will be cross-platform compatible.

Thanks for the interest and the work! Stay tuned :D

Exciting to hear about that! Thanks for your contribution to the community. I have already recommended your work to my colleagues.