You could do what mrhaw recommended, either use a template just for the video section with the embedding code allready present. Or you can use a TV for the embedding code (TVs can be assigned to user groups so that you can make it so that they are only available for users of a specific group for editing but are rendered to all groups in the front end). I use this all of the time to add fields that only an admin can edit.
I often add a ’secret’ TV directly above or bellow the content where i can run Ditto calls or other stuff that I want to keep away from regular users.
[*preContent*] <-only defined user group can edit
[*content*] <-every user can edit
[*postContent*] <-only defined user group can edit
You can also use a snippet to read if there is a value in a TV and if so render the output.
Or you can do the same thing with PHx (there is documentation in the wiki on PHx but the wiki is temporarily down).
And yet another option is to use a ’default’ document that you use as a mold to copy from where the TV values are blank but the content is not. Name it like "Duplicate Me" and leave it unpublished. Then you can edit the home page of te manager and add a custom button "Add New Video" that would simply duplicate the ’default’ document (there is a wiki on customizing the manager home)
And there is even another option, you could populate the content of the new documents in the Video section by using a plugin.
There are a few ideas, I am sure there are others. Maybe ManagerManager can populate fields.
MODx = Options