流式视频服务器和客户机的 实现

1、流式视频服务器和客户机的实现钱叶魁主要内容 目标和功能 采用的方法原理 实现目标和功能 实现流式视频服务器和客户机流式存储视频应用 客户机发送SETUP,PLAY,PAUSE和TEARDOWN等RTSP命令，并且服务器应答这些命令； 当服务器处于播放状态时，它周期性地抓取JPEG帧，用RTP对该帧分组化，并将该RTP分组发送到一个UDP套接字中； 客户机接收该RTP分组，解压缩JPEG帧，并在客户机显示器上显示。采用的方法和原理 RTSP RTPRTSP运行过程Presentation Description文件例子Twister RTSP Exchange Example C: SETUP

2、rtsp:/ RTSP/1.0 Cseq：1 Transport: rtp/udp; compression; port=3056; mode=PLAY S: RTSP/1.0 200 OK Cseq：1 Session 4231 C: PLAY rtsp:/ RTSP/1.0 Cseq：2 Range: npt=0- Session: 4231 C: PAUSE rtsp:/ RTSP/1.0 Cseq：3 Range: npt=37 Session: 4231 C: TEARDOWN rtsp:/ RTSP/1.0 Cseq：4 Session: 4231 S: RTSP/1.0 200

3、3 OK Cseq：4 Session: 4231 RTP runs on top of UDPRTP libraries provide a transport-layer interface that extend UDP: port numbers IP addresses payload type identification packet sequence numbering time-stampingUDPRTPRTP HeaderPayload Type (7 bits): Indicates type of encoding currently being used. If s

4、ender changes encoding in middle of conference, sender informs the receiver through this payload type field. Payload type 0: PCM mu-law, 64 kbpsPayload type 3, GSM, 13 kbpsPayload type 7, LPC, 2.4 kbpsPayload type 26, Motion JPEGPayload type 31. H.261Payload type 33, MPEG2 videoSequence Number (16 bits): Increments by one for each RTP packet sent, and may be used to detect packet loss and to restore packet sequence.RTP Header (2)Timestamp field (32 bytes long). Reflects the sampling instant of the first byte in the RTP data packet. SSRC field (32 bits long). Identifies the source o