Abstract: An elementary stream packetizing unit for an MPEG-2 system comprising a system time clock generator for sampling an external system clock signal at a resolution of a predetermined frequency, first and second time stamp generators for latching a sampled value from the system time clock generator to generate a first presentation time stamp and a decoding time stamp for the process of video elementary stream data and a second presentation time stamp for the process of audio elementary stream data, respectively, first and second stream interface circuits for inputting the video and audio elementary stream data and generating a group-of-picture detect signal and an audio frame synchronous word detection start signal, respectively, first and second buffers for storing the video and audio elementary stream data and generating first and second header generation start signals, respectively, first and second header generators for generating first and second headers, respectively, a first multiplexer for multiplexing th