TASHKENT UNIVERSITY OF INFORMATION TECHNOLOGIES THE DEPARTMENT OF DATA COMMUNICATION NETWORKS AND SYSTEMS Lector: Aliyev H.U. Lecture №15: Telecommunication network software design multimedia services.
Introduction • With the great advances in digital data compression (coding) technologies and the rapid growth in the use of IP-based Internet, along with the quick deployment of last-mile wireline and wireless broadband access, networked multimedia applications have created a tremendous impact on computing and network infrastructures. The four most critical and indispensable components involved in a multimedia networking system are: (1) data compression (source encoding) of multimedia data sources, e.g., speech, audio, image, and video; (2) quality of service (QoS) streaming architecture design issues for multimedia delivery over best-effort IP networks; (3) effective dissemination multimedia over heterogeneous IP wireless broadband networks, where the QoS is further degraded owing to the dynamic changes in end-to-end available bandwidth caused by wireless fading or shadowing and link adaptation; (4) effective digital rights management and adaptation schemes, which are needed to ensure proper intellectual property management and protection of networked multimedia content. • With the great advances of digital data compression (coding) technologies, traditional • analog TV and radio broadcasting is gradually being replaced by digital broadcasting. With better resolution, better quality, and higher noise immunity, digital broadcasting can also potentially be integrated with interaction capabilities.
Multimedia services in networks • With the great advances of digital data compression (coding) technologies, traditional analog TV and radio broadcasting is gradually being replaced by digital broadcasting. With better resolution, better quality, and higher noise immunity, digital broadcasting can also potentially be integrated with interaction capabilities. • In the meantime, the use of IP-based Internet is growing rapidly , both in business and home usage. The quick deployment of last-mile broadband access, such as DSL/cable/T1 and even optical fiber, makes Internet usage even more popular. One convincing example of such popularity is the global use of voice over IP (VoIP), which is replacing traditional public-switched telephone networks (PSTNs). Moreover, local area networks (LANs, IEEE 802.3 ) or wireless LANs (WLANs, also called Wi-Fi, 802.11 ), based on office or home networking, enable the connecting integration and content sharing of all office or home electronic appliances (e.g., computers, media centers, set-top boxes, personal digital assistants (PDAs), and smart phones). As outlined in the vision of the Digital Living Network Alliance (DLNA), a digital home should consist of a network of consumer electronics, mobile and PC devices that cooperate transparently, delivering simple, seamless interoperability so as to enhance and enrich user experiences. Even the recent portable MP3 players are equipped with Wi-Fi connections. Wireless connections are, further, demanded outside the office or home, resulting in the fast growing use of mobile Internet whenever people are on the move. • These phenomena reflect two societal trends on paradigm shifts: a shift from digital broadcasting to multimedia streaming over IP networks and a shift from wired Internet to wireless Internet. Digital broadcasting services (e.g., digital cable for enhanced definition TV (EDTV) and high-definition TV (HDTV) broadcasting, direct TV via direct broadcast satellite (DBS) services , and digital video broadcasting (DVB) are maturing, while people also spend more time on the Internet browsing, watching video or movie by means of on-demand services, etc.
Interactive multimedia services take advantage of the bidirectional communication media of IP networks
Building a client–server video streaming system • We have explained how to capture, playback, encode, and decode video and audio data. We will now add one more component to the previous capture and playback application in order to provide network capability. Our main objective in this section is to enable the sending of video data from the server machine to the client machine. More specifically, we use the following procedure. • Add a socket class to the video capture application to make a video server. • Add a socket class to the video playback application to make a video client. • The basic algorithm for a video client or server is quite similar to that for video capture and playback. The difference here is that instead of saving the video to a file we first encode the video file so that it can be compressed, then pocketsize the video data and send it through the network. The client will receive the packet, extract the encoded data from the packet, decode the file, and display it on the screen.