INTERNET TV TELECASTING EXPERIENCES

INTERNET TV TELECASTING EXPERIENCES AT THE SAMARA REGIONAL NETWORK FOR SCIENCE AND EDUCATION

Today’s Universities are increasingly seeing the need to disseminate their wide assortment of educational and scientific information on the Internet. For this, several specialized portals and collaboration technologies with web-interfaces are being developed. A common component in these mediums is the use of multimedia i.e. voice and video, for content delivery. Consequently, Universities are beginning to adopt and support video broadcasting services.

With the capacities of Internet backbones increasing dramatically in the last few years, video broadcasting for Universities has become a viable and affordable option. However, several questions still remain to be thoroughly answered such as:

  • Is the current Internet infrastructure ready to support streaming multimedia demands of Universities?
  • What additional design and planning considerations need to be handled both by the Universities and the network backbone operators for successful broadcasting?

This article describes our attempts to investigate answers to the above questions using our experiences in supporting Internet TV channel services at the Samara Regional Network for Science and Education, Russia.

From April 2006, a University Internet TV service (www.ip4tv.ru) has been started at the Samara Regional Network for Science and Education, which interconnects all state Universities, majority of private higher education establishments, all institutes of Russian Academy of Science, major libraries, clinics and municipal bodies. About 50,000 audiences at 15,000 sites are expected to be receiving our broadcasting services. We also have garned the support of major ISPs and companies of cable TV in our efforts.

Our constraints in setting up the Internet TV service were to limit the initial production cost by having a small time for installation and start of service. We successfully setup the service within a months’ time using simple technology solutions. Our technology solution can be presented as shown in Figure 1.

 

Internet TV Service Architecture

Figure 1: Internet TV Service Architecture

 

 

The four basic blocks of the Internet TV service could be separated as:

  1. Video codec block that transforms the continuous video information in digital form and compresses for the next stage.
  2. Stream encoder block divides the compressed data into IP packets (RTP/UDP) for network transmission.
  3. Reflector block is a special server that duplicates IP packets using multicast for handling multiple users.
  4. Media player block is the special software program installed at the end user sites for viewing TV channels.

We use MPEG-4 (H.264) for video compression. The core part of Internet broadcasting is multicasting that supposes the transmission of united streams on paths that coincide for several end user sites. At the branching points, IP packets are duplicated thus reducing the overhead of broadcasting to all the end user sites. Further, the use of multicast delivery allows traffic tariff to be a fixed payment.

We employ two variants of delivering multicast:

  1. Using expensive network devices with multicast support
  2. Using special reflectors for packet duplication to end user sites. This variant makes it possible to realize multicast on network paths managed by multiple ISPs.

Unfortunately, all the four blocks shown in Figure 1 are not sold in entirety by any of the leading vendors. For example, Polycom, Tandberg, Real Networks, Microsoft do not incorporate the reflectors in their solutions. For our project we choose a product called “Vidicor” that was designed by Vidicor ltd (http://vidicor.com) on the basis of the research conducted by the Center of Multimedia Technology of Institute of Mechanics and Mathematics of UB RAS. Comparisons with products of leaders: Polycom, Tandberg, Real Networks, Microsoft showed that it was more cost effective and also delivered excellent quality of video sequences. Vidicor solution contains a stream server with MPEG4 video codec, video on demand, reflector software and player.

Our model of University TV includes interactive components, which suppose the reverse multimedia channels from the auditoria. The telephone line, SMS and MMS messages, videoconferencing in 3G and Internet have been chosen as reverse channel options. Interactive TV demands new design of screen formats that includes windows for power point slide presentation simultaneously with video stream windows.In our basic use-case, we have atleast three windows:

  • a. Data (current slide of presentation)
  • b. Lecturer, speaker
  • c. Interlocutor

From the networking point of view to support such Internet TV use-cases, there are two considerable challenges: (i) the construction of reflector networks and (ii) the selection of video stream parameters. The construction of reflector network (superimposed multicasting system) mainly demands proper design efforts. The selection of video stream parameters such as stream bandwidth, frame frequency, codec types, window size, etc. demands careful experimentation and configuration. In our earlier work [TNC 2005], we constructed an analytical model that described the behavior of high-speed audiovisual streams in IP based networks. Our model allowed us to calculate the video quality from parameters of network connection – jitter and packet loss. We used our experience from developing our model to set QoS expectations along two dimensions: First dimension for Russian only translations uses - 650 Kbps, 25 fps, CIF, Q-MOS=4.2. The second dimension for all Russian and foreign translations uses - 250 Kbps, 12-20 fps, CIF, Q-MOS=3.9 –4.0.

The programming policy of our channel primarily consists of delivering telecasts interesting to Unviersity demographics. The telecasts involve lessons, leading conference and workshops and defenses of thesis. There are place-holders in the programming for entertainment programs: student performances, amateur night, etc. As first experiment we have organized the telecast of amateur performances of Samara State Aerospace University (SSAU) and of Samara Academy of Transport Engineering. The collaboration with local broadcasting stations has allowed us to reach a much wider audience. In addition, we have organized the telecast of several conferences, for example- “Information Technologies in Education – Middle Volga Region. 2006”. Further, we have telecast workshops such as the visit of Holland students organized by European Space Agency in August 2006. Several interviews have been recorded involving speeches of the Dean of Information Technology department, Chine’s students studies in SSAU, etc.

Our next aim is to successfully deliver interactive TV channels in formats suitable for telecast using content generated from MMS and web camera platforms at the end user sites. Reference:

[TNC 2005] A. Sukhov, P. Calyam, W. Daly, A. Illin, “Towards an Analytical Model for characterizing behavior of High-Speed VVoIP applications", TERENA Networking Conference (TNC), Proceedings published by PSNC in “Journal of Computational Methods”, 2005.


Authors:

Andrei Sukhov, Internet TV ltd., Morkvashinskaya 3, PO BOX 87, Zhigulevsk-4, Samara reg., 445354, Russia, e-mail: Этот e-mail адрес защищен от спам-ботов, для его просмотра у Вас должен быть включен Javascript

Mikhail Strizhov, Samara State Aerospace University, Moskowskoe sh., 34a, Samara, 443086, Russia; e-mail: Этот e-mail адрес защищен от спам-ботов, для его просмотра у Вас должен быть включен Javascript

Alexey Platonov, Russian Institute for Public Networks, Kurchatov Square, 1, Moscow, 123182, Russia; e-mail: Этот e-mail адрес защищен от спам-ботов, для его просмотра у Вас должен быть включен Javascript

Prasad Calyam, OARnet, The Ohio State University, Ohio, USA; e-mail: Этот e-mail адрес защищен от спам-ботов, для его просмотра у Вас должен быть включен Javascript


 
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