A video-processing assembly (1), particularly for an endoscope, including a video-processing device (2) and an expansion device (3), which is connected to the video-processing device (2) via an interface (14). The interface (14) transmits at least two video data channels (8, 13), a primary video data channel (8) processed in the video-processing device (2) and the secondary video data channel (13) being led unprocessed into the expansion device (3) and processed there. The two processed video signals are combined in a mixing unit (15) in the expansion device (3) and transmitted to an image display device (11).