How Streaming Media Works

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Learn how streaming works (Created in 2006 as part of my IT 665 Networking course)


  • 1. 1How Streaming Media WorksBilguun GinjbaatarIT 665

2. 2Outline Introduction: Whats Streaming? Source Material for Streaming Streaming Technology Streaming Servers Media Players Streaming Audio Streaming Video Bandwidth How Does Edinboro University broadcast? Protocols 3. 3 4. 4Playing compressed video or sound in real time asit is downloaded over the internet 5. 5 6. 6 7. 7 8. 8 9. 9 10. 10 11. 11 12. SSttrreeaammiinngg AAuuddiioo11.. CCaappttuurree AAuuddiioo SSoouurrccee-Microphone-CD11.. OOppttiimmiizziinngg tthhee AAuuddiioo SSoouurrccee-Use sound editor3. EEnnccooddiinngg tthhee ssttrreeaammiinngg aauuddiioocclliipp-choose streaming format-choose one or several streamingbandwidth4. DDeelliivveerr tthhee ssttrreeaammiinngg aauuddiioo cclliipp-broadcast is available throughwebsite-If combined with another streamingclip, create SMIL file. 13. 13SSttrreeaammiinngg AAuuddiioo BBiitt RRaatteessInternet Radio=56 Kbps, Talk show=32 Kbps, Stereo & CD Quality=256 Kbps 14. 14AApppplliiccaattiioonnss 15. 15SSttrreeaammiinngg BBaannddwwiiddtthh aanndd SSttoorraaggee Usual Video window size: 320 x 240 Streaming Media Storage Size Megabytes Gigabytes Terabytes Whats the Storage Size for 1 hour of video, encoded at 300kb/s? 16. 16Streaming Video (Webcast) 17. 17How does EUP broadcast theCommencement Ceremony?Firewirehttp:// Media EncoderWindows 2003 Serverhttp:// Port 1185Ross Hall64Kbps256 Kbps 18. 18Protocols User Datagram Protocol(UDP) Real-Time Streaming Protocol(RTSP) Real Data Transport(RDT) Real-time Transport Protocol(RTP) Real-Time Transfer Control Protocol(RTCP) Resource ReSerVation Protocol(RSVP) 19. 19UDP Sends media as series of small packets Provides connectionless & best-effort message service Simple & efficient Packets are liable to be lost or corrupted Client may use Error Correction to recover data or Drop Out 20. 20RTSP Developed in 1998 as RFC-2326 Allows client remotely control: play, pause, next Clients: RealPlayer, VideoLAN, MPlayer, Windows MP, Quicktime Session ID is used to keep track No permanent TCP connection needed RTSP requests based on HTTP DESCRIBE: includes rtsp:// SETUP: request specifies how a single media stream must betransported PLAY: request will cause one or all media streams to be played RECORD: used to send a stream to the server for storage TEARDWON: used to terminate the session 21. 21RDT Real Data Transport proprietary transport protocol foraudio/video Developed by RealNetworks in 1990s. Tolerant to loss. Works in companion with RTSP. Uses ports: 16384 32767 22. 22RTP Real-time Transport Protocol Provides end-to-end delivery interactive audio/video overthe internet. Can be used for VOIP applications: Skype, VoipCheap 1996: RFC 1889 => 2003: RFC 3550 Does not have standard TCP or UDP port to communicate UDP connections are done only via an 2n port. 2n+1 port is used for RTCP communications. 23. 23RTP PacketReal-time Transport Protocol 24. 24RTCP Sister protocol of Real-time Transport Protocol (RTP) Defined in RFC 3550 Partners with RTP in delivery of multimedia data DOES NOT transport any data itself Monitors participating packets in steaming multimedia session. Sends control packet to get feedback on QoS Gathers stat info on: bytes sent, bytes received, lost packets, jitter,roundtrip delay Types of RTCP: Sender Report Packet Receiver Report Packet Source Description RTCP packet Goodbye RTCP packet SRTCP (Secure) is used for encryption, authentication, and integrity 25. 25RSVP Transport Layer protocol designed to reserve resources across theInternet Described in RFC 3936 (Oct 2004) Can be used by HOSTS or ROUTERS Delivers specific QoS for data streams RSVP is not a routing a protocol, but works with other routingprocols. Notice: RSVP is rarely deployed by tele-com networks today Traffice Engineering RSVP (RSVP-TE) is available now. RSVP requests resources for simplex flows: a traffic stream in onlyone direction from sender to one or more receivers. 26. 26Conclusion Streaming is used widely everywhere To stream a media you will need: camera, firewire, encoder, server,and a high speed internet connection Media Players: Adobe Flash Player, Windows Media Player. How Streaming Audio & Video works. Streaming Bit Rates differ: higher the bit rate the better quality. The Protocols used: User Datagram Protocol (UDP) Real-Time Streaming Protocol (RTSP) Real Data Transport (RDT) Real-time Transport Protocol (RTP) Real-Time Transfer Control Protocol (RTCP) Resource ReSerVation Protocol (RSVP) 27. 27Reference