A method of adding advertisements to a video stream. The method includes storing for each of a plurality of advertisements, a plurality of versions of the advertisement including same advertisement content with different overlay indications of relative location of the advertisement in an advertisement session. Upon receiving an indication of a video stream, the method includes selecting advertisements for insertion into the video stream, selecting relative positions of the selected advertisements in one or more advertisement sessions in the video stream, identifying for each of the selected advertisements, one of the plurality of versions of the advertisement corresponding to the selected relative position of the advertisement in the one or more advertisement sessions, and providing an indication of the video stream with the identified versions in the selected relative positions.