System for multiplexing video data streams in a digital video recorder and method of operating the same

There is disclosed systems for multiplexing packetized elementary streams in a digital video recorder (DVR), methods of operating the same, and multiplexed program streams. One such system is associated with a DVR and operates to multiplex packetized elementary streams into a multiplexed program stream, the packetized elementary streams comprising PES packets of disparate size. The system is operable to (i) receive the PES packets into a memory buffer, (ii) reformat each of the received PES packets into at least one fixed-size program packet having a header and a payload, the header defining a payload content, and (iii) associate ones of the at least one fixed-size program packets into the multiplexed program stream.