It is the "Enhanced Switching" video (part 1, the first video after the intro video) in the Accelerated CCNA Routing and Switching course. I think the first time he mentions it is at time 14:50 and then again at 25:13 when he's summarizing.
Thanks for looking into it.
In the Accelerated CCNA R&S video, Enhanced Switching, Todd says that the designated port is determined by the BID. However, in CCNA Offical Cert Guide book and the Cisco documentation I've found (see below), the first check is based on the path cost between the switches, not the BID. Is Todd wrong or am I misunderstanding something?
From the Cisco documentation, page 15-3::
"A designated switch for each LAN segment is selected. The designated switch incurs the lowest path cost when forwarding packets from that LAN to the root switch. The port through which the designated switch is attached to the LAN is called the designated port."