In one aspect, an example method for outputting an alert indicating a functional state of a back-up video-broadcast system involves: a computing device receiving a first video-stream that represents first video-content; the computing device generating a first signature based, at least in part, upon an extent of scene-change transitions included within the first video-content; the computing device receiving a second video-stream that represents second video-content; the computing device generating a second signature based, at least in part, upon an extent of scene-change transitions included within the second video-content; the computing device making a determination that the generated first-signature and the generated second-signature lack a threshold extent of similarity; and responsive to the determination that the generated first-signature and the generated second-signature lack the threshold extent of similarity, the computing device outputting an alert.