Data videos -- motion graphics that incorporate visualizations -- have been recognized as an effective way to communicate ideas, but creating such video requires both time and expertise, precluding them from being created and streamed live. We introduce DataTV, a system for combining multiple media sources in real time. We validate our work through an expert review involving researchers using the DataTV prototype to create a one-minute data video for their current project. Results show that the new method facilitates rapid creation and enables users to focus on the narrative rather than mechanics of video production.