MEDIA RETRANSMISSION DEVICE AND A METHOD, SPECIFICALLY CONCERNED WITH GUARANTEEING ACCURACY IN MEDIA DATA AND IMPROVING A DATA QUALITY THROUGH A RETRANSMISSION TECHNIQUE

摘要

PURPOSE: A media retransmission device and a method are provided to continuously confirm sequence numbers of received stream packets, and to replay from a lost stream packet through a retransmission request reflecting a current play time for the lost stream packet if the stream packet is lost, thereby preventing image and audio qualities from deteriorating while guaranteeing accuracy in media data. CONSTITUTION: A client(10) comprises as follows. A network protocol stack(11) temporarily stores received stream packets. A sequence number confirmer(13) reads the stored stream packets one by one, and decides whether the stream packets are lost. If one of the stream packets is lost, an NPT(Normal Play Time) calculator(14) calculates a current NPT from the corresponding stream packet. An RTSP(Real-Time Streaming Protocol) reaction processor(15) generates a retransmission command reflecting the calculated current NPT. An RTSP processor(19) transmits the retransmission command to a server. If any of the stream packets is not lost, a buffer(16) buffers the stream packets. An A/V decoder(18) decodes the buffered stream packets to play the packets. A decoding controller(17) sends the buffered stream packets to the A/V decoder(18).