There are multiple ways that access and video surveillance are integrated together. Usually this means choosing one platform and integrating the features of the other into it.
For example, I can integrate access control into my VMS system, where I maintain the full depth of control of video and only integrate a select number of access system controls into the interface (eg: lock/unlock, door hold open alarms, user/credential card reads).
The opposite is often true as well: I can take a full featured access management platform (eg: badge printing, user management, etc) and integrate some video features into it like door open event playback, PTZ controls, rudimentary video searching, and live view.
Based on your experience or preference, which platform is the 'Top Box', or 'Primary Interface'? The VMS or EAC management platform?