A client device accesses a video input stream from an intermediate device for display. The client device analyzes the video input stream to determine that the video input stream matches a template indicating a change of content source. The analysis is performed while the client device is generating a video output stream that replaces video content received from a content source via the intermediate device. Based on the video input stream matching the template, the client device ceases replacement of the video input stream. The client device continues to analyze the video input stream and determines that the video input stream matches a second template indicating a return to the original content source. Based on the video input stream matching the second template, the client device resumes replacement of the video input stream.