Packet transmission apparatus and method, and packet reception apparatus and method in mmt system

PURPOSE: A packet transmission device and method, and a packet reception device and method are provided to efficiently perform synchronization of packet transmitted through an MPEG-2 system or RTP without opposing the existing standard. CONSTITUTION: A packet transmission device(10) includes an audio encoder(110), an audio buffer(120), a video encoder(130), a video buffer(140), an MMT packetization unit(150) and an STC(System Time Cock)(160). The audio encoder encodes an audio block of contents. The audio buffer outputs audio data with a constant rate. The video encoder generates a video stream by encoding pictures. The video buffer stores an encoded video stream. The MMT packetization unit generates an MMT packet after packetizing a video stream and an audio stream corresponding to the video stream. The STC is a master clock of the video encoder and audio encoder for a program. [Reference numerals] (110) Audio encoder; (120) Audio buffer; (130) Video encoder; (140) Video buffer; (150) MMT packetization unit; (20) IP network; (30) Receiving device; (AA) i-th picture input; (BB) MMT buffering delay