in general , one aspect of the subject matter described in this specification can be embodied in a system that includes a user interface device ; and one or more computers operable to interact with the user interface device and to perform operations including : receiving video data ; applying a one dimensional watermark pattern to each of multiple one dimensional data lines in the video data to create watermarked video data ; receiving the watermarked video data including the multiple one dimensional data lines ; combining the one dimensional data lines to form a one dimensional array of numbers ; analyzing the one dimensional array of numbers to detect the one dimensional watermark pattern previously applied to each of the one dimensional data lines ; and outputting an indication of a match , to trigger further processing with respect to the watermarked video data , when the analyzing indicates the watermark pattern has been detected .