Disclosed are a method, a controlling device (110), a controllable device (130) and an arrangement (100) for communicating a command from the controlling device (110) to the controllable device (130). A watermark is generated comprising the command, and embedded in a signal (120) representing an audio or video fragment. The controllable device (130) receives the signal (120) comprising the command, and decodes and executes the command therefrom. Also disclosed is a method of presenting an advertisement which involves sending a command related to presenting the advertisement using the above-mentioned method.