Method of processing received audio/visual data stream when programme clock reference (PCR) data is not included in selected programme-related packets

摘要

A method of operating an audio/video (AV) content receiver (e.g. set-top box (STB)) having a decoder for an audio/video programme from a packetized data stream, using data packets defining decryption information, comprises: receiving encoded content as packetized data streams comprising one or more programmes having data packets identified by respective sets of one or more packet identifiers (PIDs) and identification data mapping programmes to respective sets of packet identifiers; selecting data packets from the stream for each required programme according to the set of packet identifiers defined by the identification data for that stream in respect of the required programme; selecting further, additional data packets from each packetized data stream from which a programme is selected which contain programme clock reference (PCR) data relating to the selected programme, in the case that programme clock reference (PCR) data is not included in the packets relating to the selected programme; generating a composite packetized data stream from selected packets; generating composite stream identification data defining the packet identifiers of data packets in the composite packetized data stream; and supplying the composite packetized data stream for decoding according to the PCR and packet identifiers in the composite stream identification data.