Whether it is an open class, a special lecture or a training class, it involves intellectual property issues. Without the consent of the speaker/trainer, it is illegal to spread and use (different from "quoting") the original version of the speech/training form and content, and the intellectual property owner can sue and pursue legal responsibility. So if you want to record and video, you must get the consent of the speaker/trainer.

If lectures and training are systematic and conducted through an institution, its intellectual property usually belongs to that institution. It is also necessary to obtain the permission of this institution.