The release of macOS 10.14 Mojave broke all video and image capture functions in Logger Pro. It is still possible to analyze existing videos and photos, but not to capture new content.
On 10.14 only: Instead of using Logger Pro to capture video, we suggest using the app Quicktime Player, included with the operating system. Quicktime Player will perform video capture from a variety of attached cameras, including built-in web cameras. Quicktime Player allows you to trim captured video and then save it to a files. Once saved, insert in a Logger Pro session for video analysis.
There is no workaround on 10.15 at the current time. In 2020 there will be a release labeled 3.16 that will restore video analysis and possibly video capture.
Workarounds with Logger Pro include using a computer with an older macOS version or a Windows PC.
Regarding the capture issue, Mojave introduced a permission model for camera and microphone access by applications. In Mojave, programs need to request access to all cameras attached to the system. Apple only provides a way to grant permission to applications built on certain new video frameworks. Logger Pro uses an older video framework that supports older operating systems.