System and method for generating multiple independent, synchronized local timestamps

A method, in a multimedia processing device, for processing a plurality of data packets received from a plurality of program sources multiplexed in a single data stream, the method comprising the steps of:

• receiving the plurality of data packets from the plurality of program sources in the multiplexed data stream;
• distributing the data packets to a plurality of local timestamp insertion modules wherein each local timestamp insertion module is associated with a corresponding one of the plurality of program sources;
• in each local program timestamp insertion module,
• synchronizing a local program clock to a system time clock of the associated one of the plurality of program sources,
• generating a local program timestamp using the synchronized local program clock, wherein the local program clocks operate independently;
• and
• appending the local program timestamp to each received data packet;
• distributing a set of data packets to a transmissions module;
• for each data packet in the set of data packets,
• determining a delay introduced by processing within the multimedia processing device using the local program timestamp for the data packet;
• updating a clock reference value for the data packet to account for the delay;
• and
• removing the local program timestamp from the data packet prior to transmission.

A method, in a media processing device, for updating a clock reference value contained in a plurality of data packets in a multiplexed data stream, each data packet including a program identifier and program data, the method comprising the steps of:

• extracting a set of data packets from the multiplexed data stream having a first program identifier;
• synchronizing a local program reference clock with a clock associated with a source of the program data included in the set of data packets;
• for each data packet in the set of data packets,
• appending a local program timestamp to the data packet based on the local program reference clock;
• determining whether the data packet being processed contains a clock reference value;
• determining the difference between the current value of the local program clock used to generate the local program timestamp and the value of the appended local program timestamp;
• adding the difference to the clock reference value contained in the data packet to generate an updated clock reference value for the data packet;
• and
• removing the local program timestamp from the data packet prior to transmission of the data packet.