659. Teaching during the pandemic, part 2: Recording with two cameras (on linux)

This is a very short post. What if you need to set up two (web)cameras that capture from e.g. different whiteboards?

I had a look at OBS studio, and it's not stable for me. Sometimes I get a cam image, and sometimes I don't. I also had issues with getting two cameras to work. I also looked at webcamoid and cheese. The frame rates were too bad.

What does work for me is guvcview. This is available in the debian repos.

I'll also show you how to sync the sound using KDENLive

1. Install guvcview
sudo apt-get install guvcview

2. Start guvcview.
Then go to video controls.

Select a new Device, then select New

Now you've got both feeds showing:

Then you can simply record:

I won't go into how to switch back and forth between angles in KDENLive. I'll just show you how to sync the videos using the audio:

Import both clips into KDENLive and put them in separate channels. Right-click on one of the tracks, and make it the audio reference:

Align the other clip:

They are now aligned:

Note that you could have done this with a pure audio track as well (we'll get to that in the next post).

You can then start cutting away bits you don't want using the x/scissors:

654. Screen-casting on linux (debian 9)

Minipost:
I'm interested in making course videos where I show my desktop (I might have a full-screen presentation going), but where I also want to show my face.

I'm using debian.

Solution:
To screen-cast the desktop I'm using EasyScreenCast, which is a Gnome Extension: https://extensions.gnome.org/extension/690/easyscreencast/

Not much to say about it really, other than that it works very well.

To get my face on the desktop I use guvcview, which is in the repos.

To make guvcview stay on top even during a full-screen presentation I followed this: https://www.linuxquestions.org/questions/linux-general-1/how-to-make-guvcview-stay-always-on-top-4175541777/

My son's orca lecturing on the importance of experiments in formulating new theories

kdenlive seems like an interesting editor for post-production, but I haven't got that far yet.