Share documents outside the organisation?

We have it on our roadmap for external sharing of videos on Stream but we are just in planning phase now.

We did enable O365 Video to do named guest access at the Channel level though a series of steps and powershell commands. We aren't widely advertising it, as that method won't work once a customer does move from O365 Video to Stream, as when we build this in Stream will be a different mechanism. So if your client wants to use this external guest option on O365 Video channel until the point when they move to Stream that is an option. You can send me a private message and I'll give you the series of steps to enable it on a O365 Video channel.

SharePoint Online and/or ODB is your other option for external sharing of videos outside your organization today.