Abstract:
A method of transcoding a sub-picture unit each comprising encoded sub-picture pixel data including sub-picture lines separated into at least a first field and a second field as well as a set of display control commands associated with the sub-picture pixel data, comprises the step of pre-processing (53) the display control commands to prepare transcoding to frame format. Encoded lines of said top and bottom fields are then merged (56,73) into a single encoded frame and the display control commands are modified (56,74) according to changes in encoded sub-picture pixel data before outputting.