Internet TV

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Lectures from the broadcast multimedia course held in TUT

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Internet TV

  1. 1. Internet TV – Yet another TV ?? Broadcast Multimedia course – TUT - 2008 Adrian Hornsby
  2. 2. Short on Internet Internet  − world's largest computer network − collection of smaller networks, computers, and people who use them. − around 28 million people Until recently, multimedia and internet were not  really going together − Not enough bandwidth, load, errors, traffic ...
  3. 3. Yet another one ... Digital Media Revolution … • Huge increase in media content • Faster communications • New user experience • New consumer demand New digital devices + new digital transmission systems = New digital transmission system 10/29/08
  4. 4. Yet another TV system !!! Internet Television (TV), iTV  − Television like content distributed through the internet. Running on existing IP infrastructure (DSL, Wifi, 3G data ...)  Distribution model  − Live Streaming − VOD − But also P2P (P2PTV)
  5. 5. Tell me more ... Differ from IPTV  − Not a dedicated network but over the internet No real QoS  − Does not require set-top box − Provider not always clear Legal and none legal content  − Quick to market with Low investment cost − Usually uses advertisement as main revenue
  6. 6. And how does that one works ?? Browser + media player (plugins)  − No special equipment, just a computer and a connection to internet Several options ...  − HTTP streaming (basic and advanced flavor) − RTP based multicast streaming − RTSP based streaming
  7. 7. HTTP streaming ? hmm ... (basic flavor) Simplest and cheapest way to stream video  from a website No special type of website or host  − recognizes common video file types Good option for websites with modest traffic  No live video  − HTTP method needs complete files stored on the server. − No automatic detection of end user's connection speed different file for different speeds 
  8. 8. HTTP streaming (basic flavor) HTTP-like live streaming  1- Clients request with HTTP-Get message 2- Server replies with a HTTP-OK response 3- ... continuous stream of data (usually port 8000) 4- Also referred as HTTP-push long-lived HTTP connection.  keep the connection open by running a long loop 
  9. 9. HTTP streaming basic flavor Web Browser HTTP meta file Web HTTP content Server Media Player
  10. 10. HTTP streaming (advanced flavor) Similar to basic flavor except media sent by  specialized streaming media server − Data delivery process differs No passive http push technique  Data send actively and intelligently,  − eg. data rate associated with compressed media streams Server and client in touch, responses to feedbacks  Stream usually controlled by ZeroWindow / KeepAlive  mechanism − Receiving host use the window field in each acknowledgment to inform the sending host how much more data it can receive [rfc793],0 if receiver is pausing the stream. When playing resumes, the receiver sends another ACK with a nonzero window size.
  11. 11. HTTP streaming (advanced flavor) Web Browser HTTP meta file Web Server Media Player HTTP media content Streaming Server
  12. 12. ... hmm I prefer advanced flavor ! More efficient network throughput  Better audio and video quality  Support for advanced features  Larger number of users  Content copyright handling  Multiple delivery options 
  13. 13. HTTP streaming servers example Basic flavor  − Apache Special flavor  − Shoutcast − Icecast − VLC − Window media server
  14. 14. RTP-based streaming So called multicast streaming  − requires global multicast address (€€) − No subscription subscription Combining RTP over UDP  More for Live events, no “real” control on  stream
  15. 15. Real-Time Transport Protocol (RTP) (optional) RTP packet (V) RTP Compressed video header RTP Profile RTP packet (A) RTP IP UDP RTP Compressed sound header RTCP packet (C) (option) RTP Sender/Receiver report header UDP packet RTP Profile UDP IP UDP RTP header
  16. 16. How does my device access the media stream ?? Listen SAP announcement (default 224.2.127.254:9875)  SDP1 SDP2 SDP3 SDP4 SDP5 SDP6 SDPn Access SDP (Service Description Protocol)  v=0 o=QTSS_Play_List 1460227057 502868560 IN IP4 130.230.50.48 s=stream-32 c=IN IP4 239.252.80.5/1 b=AS:375 t=0 0 a=x-broadcastcontrol:RTSP m=video 5004 RTP/AVP 96 b=AS:248 a=rtpmap:96 MP4V-ES/90000 a=control:trackID=1 a=cliprect:0,0,240,320 a=fmtp:96 profile-level-id=1;config=000001... a=mpeg4-esid:201 m=audio 5006 RTP/AVP 97 b=AS:127 a=rtpmap:97 mpeg4-generic/44100/2 a=control:trackID=2 a=fmtp:97 profile-level-id=1;mode=AAC-hbr;...; a=mpeg4-esid:101
  17. 17. RTP streaming Web Browser HTTP Web SAP/SDP meta file Server Media Player RTP media content Streaming Server
  18. 18. RTSP based streaming For media on demand-like Internet TV  PLAY PAUSE STOP RTP
  19. 19. RTSP streaming Web Browser HTTP meta file Web Server rtsp://example.org/example/current.rm RTSP commands Media Player Streaming RTP media content Server HTTP media content (rare) RTSP may also be combained with HTTP streaming !!
  20. 20. RTP/RTSP streaming servers example VLC  Darwin  Windows Media Server  Helix  Live555  Feng 
  21. 21. Business Model Free  Pay per clip, per time  Ads  On demand / Live  Open / Proprietary (downloadable player)  Central / Distributed / P2P 
  22. 22. Internet TV and some limitations ... − Internet network − No QoS − Bandwidth issue − Poor Audio Video Quality − Interrupted Delivery − Content protection − Long Channel Zapping − Poor content − Advertising !!
  23. 23. Internet and multicast ... Broadcast Multimedia course – TUT - 2008 Adrian Hornsby
  24. 24. Short on Internet (remake) Internet  − world's largest computer network − collection of smaller networks, computers, and people who use them. − around 28 million people Until recently, multimedia and internet were not  really going together − Not enough bandwidth, load, errors, traffic ...
  25. 25. Internet and multimedia First with emails @, files ...  Then FTP and Gopher ...  Tradition of sending in one-to-one model (unicast) Recently .. explosion of digital information  Pictures, Videos, Presentations ...  Need for real-time multimedia communications  One-to-many − Bye bye unicast − Welcome multicast over the internet !!
  26. 26. Internet and multicast ... Early 90's: The Multicast Internet (quot;the MBonequot;) − region of public Internet connected by IP Multicast Critical piece of the technology needed to make multiple-person data, voice, and video conferencing on the Internet -- in fact, sharing any digital information -- cheap and convenient. [http://www.savetz.com/mbone/ch3.html]
  27. 27. Mbone .... Virtual network on top of the Internet  Invented by Van Jacobson, Steve Deering and Stephen  Casner in 1992. Minimize the traffic for shared AV conferencing  MBONE is free  − Unix based network of mrouters that support IP Multicast − enables access to real-time multimedia on the Internet tunneling protocol  − encapsulated multicast packets in unicast packets 224.0.0.0 - 239.255.255.255 
  28. 28. Mbone in the world ...
  29. 29. But it no longer exist ... Multiprotocol Extensions for BGP (MBGP)  − IETF RFC 2858 − allows different address families to be distributed in parallel − exchange of inter-domain multicast routing information − Uses PIM to build trees and forward multicast traffic.
  30. 30. M6bone What is it ??  − An IPv6 Multicast test network − M6Bone started in July 2001 − 24 networks & 45 sites Goals  − Offer IPv6 Multicast connectivity − Test and develop Ipv6 Multicast − Standardization and recommendation − Deploy advanced service on Ipv6 http://www.m6bone.net 
  31. 31. Connections schemes More details online at http://www.m6bone.net/article.php3%3Fid_article=55.html
  32. 32. Applications Mbone tools: sdr, vic, rat, nte, wb  Freeamp patches (mp3/rtp)  MIM (mpeg-1/mp3 over rtp)  ttcp and iperf  Multicast beacon (written in java), just worked for ipv6  Available content Misc vic/rat sessions  TUR (Trondheim Underground Radio)  NRK (Norwegian national broadcasting) radio channels  All global IPv4 multicast sessions (through gateway)  Maybe this time will be a success !!
  33. 33. Thanks ...
  34. 34. Open Discussion !! Can Internet TV replace traditional TV ?  What business model ?  All Internet ?  ....  Other questions ? 

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