Opencast Studio is a browser-based recording tool, that is open-source and free to use.
A demo can be found here: https://studio.opencast.org/
This tool has an integration with Opencast, but it can also be used standalone.
We also included it in Opencast 8.2 that was released this weekend, to make it easier for institutions that already use Opencast to upgrade.
A demo that deletes all content every night can be found here: https://stable.opencast.org/