If you can turn the video around in time I would include it in your “thank you for visiting/attending” emails and in your emails for the next event. I would also looking at having different edits for different audiences e.g. visitors, sponsors, exhibitors, speakers etc. Also, you could curate the footage into short versions about specific elements of your event that you can then use to promote those aspects next time across all your channels. This could be physical elements of your event such as show features, reception, displays and presentations or themed such as the networking opportunities, education, social, showcasing, recognition etc.