The vid extension has a built-in concept of a video source.
At the moment, the only video sources available are movies in the directory the model lives in and cameras attached to the computer.
The vid extension opens a new video source with the vid:<source>-open and vid:<source>-select.
These primitives change the source to the selected source.
If a source is already open, it closes it before opening a new one.
Movie sources are "stopped" after being created by vid:movie-select or vid:movie-open.
Camera sources start off as "playing" after being created by vid:camera-select or vid:camera-open.
If a source is in status "stopped" it can be started with vid:start.
Conversely, if the source is "playing" it can be stopped with vid:stop.
When a source is "stopped", each call to vid:capture-image will return the same image.
The vid extension also has the concept of a recording, a series of frames which can be sewn into an "mp4" movie.
The recorder status can be queried using vid:recorder-status.
The recorder status is "inactive" until started with vid:start-recorder, which sets it to "recording".
While the recorder is "recording" the vid:record-view, vid:record-interface, and vid:record-source can be used to save frames to the recording.
You can choose to save the recording while recording using vid:save-recording which saves the movie to the specified file and reset the recording status to "inactive".
If you would prefer to throw away the recorded frames without saving, use vid:reset-recorder.
When running the extension on macOS and using vid:camera-open or vid:camera-select and then starting a different program (like Zoom) and using the same camera will crash NetLogo. If you start the other program first and then start NetLogo things should work better.