The invention relates to the generation of video displays on a display screen from video data which is received as an encoded MPEG stream of data and then decoded and processed to be displayed. In the invention the video display can be generated in a conventional format or at least one use selectable alternative format, known as trick mode stream, such as a fast forward or fast cue display. The method of the invention allows the amount of data to be placed into the buffer memory prior to decoding and display of the data in the alternate format, to be calculated without reference to the MPEG stream information which is unavailable in the trick mode stream of data. The method therefore minimizes delay in the commencement and end of the display of the trick mode stream display format when selected by the user.