It began with me wondering how I could provide more engagement during DTLT Today episodes. Monitoring a chat feed can be difficult and realistically most people watching the show live are doing so because they follow us on Twitter. Monitoring a Twitter feed is simple enough with a laptop or iPad, but I wanted to give people a reason to start tweeting. I wanted tweets to pop up live overtop our video layer during a live stream of the show. Here's how I did it.
Twitter for Mac uses the infamous Growl for desktop notifications and let's you customize exactly when you receive notifications and for which account. Since Growl notifications themselves can be customized for location, look, and time on screen it seemed this would be the perfect system to drive the notifications on the video. Using Desktop Presenter to pull a region of the computer (in my case the bottom right-hand corner of the screen) into Wirecast would give me the Twitter notifications when people replied or mentioned the show's Twitter account. Hashtag support would be cool but Twitter for Mac only supports notifications for all tweets from followers, replies/mentions, and direct messages. 
At this point we have something usable, a portion of a desktop that I can put anywhere in my shot that will automatically update with popup notifications for Twitter mentions. But it doesn't exactly look attractive. When there are no notifications the desktop background is still going to be visible. Switching to a solid black or white background is an option, but you're still wasting valuable video real estate with an area of the screen that might not be utilized more than a handful of times during a broadcast. The solution? Chroma Key. By switching the desktop background where we are getting our notifications to a solid bright green we can enable Chroma Key in Wirecast to remove the background completely. Now when we place that Desktop Presenter input on a layer overtop our video it's completely non-intrusive and only the notifications themselves will appear instead of the desktop background. The great thing about Growl is that is serves as a notification for a large variety of applications making this solution work well not just for Twitter but for a ton of scenarios. All of this has me continuing to think about how we can engage viewers both during the live show and through comments in new and innovative ways (For example using Twitter to feed the comments of individual videos on the DTLT Today site).