Patent ID: 7321602

Claim:
A method for inserting a null packet in a digital broadcasting transmission system, the method comprising: (a) removing an irregularly inserted null packet from an externally received video/audio transport stream; (b) calculating a bit rate of the removed null packet and determining the transmission period of a periodic null packet to be newly inserted in a range not exceeding the calculated bit rate of the null packet; (c) generating a periodic null packet according to the determined transmission period; (d) regularly inserting the periodic null packet preferentially and then inserting the video/audio transport stream with the irregular null packet removed, and performing multiplexing; (e) generating a non-periodic null packet and inserting the generated non-periodic null packet, when an output rate of the multiplexed transport stream is not equal to an input rate of the externally received video/audio transport stream; (f) correcting a changed PCR (Program Clock Reference) value of the multiplexed transport stream and outputting the corrected PCR value; (g) temporarily storing the video/audio transport stream, with the irregular null packet removed, in the units of a packet of a predetermined size, and outputting a stream flag signal when the stored video/audio transport stream exceeds at least one packet; and (h) temporarily storing the generated periodic null packet in the units of a packet of a predetermined size, and outputting a packet flag signal when the stored null packet exceeds at least one packet.