Editing system

An edit management system manages edits between first and second clips (A, B) each comprising video frame sequences in first and second differing formats (e.g. widescreen 16:9 or 4:3), for playout in a selected format. A means is provided to convert all frames of the first and second clips which do not conform to the selected format into that format. Also, there is means for creating an edited clip, including frames of both clips separated by an extended edit (AB) comprising respective sequences of frames of the first and second clips merged in accordance with an editing protocol to achieve a desired visual effect. The edited clip has an associated ordered sequence of data fragments, together with at least one notation or pseudo fragment recording information indicative of a format conversion relationship, dictated by the chosen protocol, between adjacent frames in the edited clip; such adjacent frames comprise a frame immediately preceding the extended edit and the first frame of the edit and/or a frame immediately succeeding the extended edit and the last extended edit frame.