International Scientific Conference Computer Science’2015
Development of IPTV system through Tvheadend® Vladimir Dimitrov1, Daniel Nedylkov2 Technical University of Sofia, Sofia, Bulgaria,
[email protected],
[email protected]
Abstract: This article examines the construction and testing of IPTV system based on Tvheadend. Using its capabilities, IPTV system is configured to broadcast multimedia content over the network. The traffic, as well as the network bandwidth and the CPU load are analyzed. Comparison of traffic is made when watching HD and SD channels. The source of the video is the established digital terrestrial television in Bulgaria. Keywords: IPTV, Tvheadend, Bandwidth, DVB-T, HDTV
1. INTRODUCTION IPTV (Internet Protocol Television) is about securely delivering high quality broadcast television and/or on-demand video and audio content over a broadband network [1] The official definition approved by the International Telecommunication Union focus group on IPTV (ITU-T FG IPTV) is as follows: IPTV is defined as multimedia services such as television/video/audio/text/graphics/data delivered over IP based networks managed to provide the required level of quality of service and experience, security, interactivity and reliability.[2] 2. EXPERIMENTAL SETTINGS FOR RESEARCH The following components are used for the construction of IPTV system: Receiver of digital television - could be satellite, cable or terrestrial. Its role is to provide TV signal to the server (HeadEnd), whose purpose is to broadcast it in the local network; Server: Software is necessary in order to broadcast the signal. This software is called streamer; Tvheadend – official website of the product: http://tvheadend.org/. It is Linux based and one of the most popular software for building IPTV home network. One of the main advantages of this product is that it offers access to a graphical interface through an Internet browser. The software runs on port 9981. The graphical interface can be accessed from a client computer connected to the server’s network. It provides only unicast distribution, which is its main drawback. It grows rapidly and offers features, such as recording TV shows and EPG. It is also a free software; VLC – website of the product: http://www.videolan.org/vlc/. VLC player itself also has the possibility of IPTV streaming. It’s is also free. It can be installed on both Linux OS and Windows OS. There is an option to transcode the signal in real time. It is also easy to setup; LAN is the connection between the server and the clients. Standard local area networks are constructed with intermediate device (router, switch, etc.) and LAN cables. In case the router and the clients’ configuration allow, the connection can also be wireless.
International Scientific Conference Computer Science’2015
Clients could be devices with different operating systems (Windows, Linux, Mac OS, Android, Windows Phone), which allows the installation of the appropriate software for receiving IPTV in LAN (VLC, XBMC, BS Player). The receiving of TV signal is carried by a DVB-T tuner called Pacostar PLE1090HD, shown in Figure 1 below:
Fig. 1: DVB-T Tuner Pacostar
The source of the TV signal is the established digital terrestrial television in Bulgaria. The multiplexers that are used have a frequency of 722 MHz and 626 MHz [3]. Detailed information about the multiplexers is shown in Table 1. Channels of these frequencies are in MPEG-4 video compression and are not pre-compressed. Tab. 1: Multiplexers – parameters [3] Frequency Modulation FEC 722 MHz
64 QAM
2/3
626 MHz
64 QAM
2/3
Guard In- Polarization terval ¼ Vertical ¼
Vertical
Video Coding MPEG-4 MPEG-4
Audio Coding MPEG-1 Layer 2 MPEG-1 Layer 2
The settings of the multiplexer from which Tvheadend takes signal are shown in Figure 2
Fig. 2: Tvheadend configuration of the adapter
Only one multiplex (frequency) can be operated with a single tuner when broadcasting IPTV. New tuner is necessary for each new multiplex. In case a new tuner is added, it shall be configured similarly.
International Scientific Conference Computer Science’2015
The PC is connected to the router through a LAN cable, and the rest of the devices are connected wirelessly to the router. The network settings of the server and the client devices are graphically presented in Figure 3. Client devices are also presented in tabular form in Table 2.
Fig. 3: Experimental Settings Tab. 2: Client Settings Type Brand Laptop Lenovo Laptop Asus Laptop Acer Smartphone Samsung PC -
Model T440 X401A V5-573G Note 2 -
OS Win 7 Win 7 Win 8.1 Android 4.1 Win XP
Software VLC VLC VLC BSPlayer VLC
Connection Wireless Wireless Wireless Wireless Wire
IP Address 192.168.1.102 192.168.1.104 192.168.1.105 192.168.1.106 192.168.1.107
A separate study is made for the comparison between HD (High Definition) and SD (Standard Definition) channels. The server is with IP address 192.168.1.100 and the client devices are described in Table 3: Tab. 3: Client Settings – HD, SD Type Brand Model Laptop Asus X401A Smartphone Samsung S3 Mini
OS Win 7 Android 4.1
Software VLC BSPlayer
Connection Wireless Wireless
IP Address 192.168.1.101 192.168.1.102
3. EXPERIMENTAL RESULTS 3.1. Network bandwidth and CPU load study The main problem of unicast distribution is the heavy traffic that is generated in the local network when watching TV. For this reason, the traffic and the overall load of the system will be the main subject of this study.
International Scientific Conference Computer Science’2015
GUI of Tvheadend offers monitoring of client devices connected to the server in real time. It provides information as to the number of clients in the network and how much traffic is generated by each one of them. Both data from Tvheadend and information from other software products taking overall system load are used for measurement. Figure 4 shows graphically the changes in the network load when 5 clients watch simultaneously. The measurement was done with the same 5 clients as shown in Figure 4. The measurement was performed using the built-in Kubuntu tool for measuring network traffic.
Fig. 4: Kubuntu – traffic for 5 clients simultaneously
Figure 5 shows the overall monitoring of the system during watching. It measures CPU load of the entire system and not just Tvheadend. The occupied RAM memory during operation of the server could also be seen.
Fig. 5: Kubuntu – Systematic Monitoring
The following two figures (6 and 7) are graphically show the changes in CPU load and network traffic increase in clients one to five. Figure 6 show the results of both the load generated by Tvheadend and the load for the entire system. The load is shown in percentage:
International Scientific Conference Computer Science’2015
%
%
Clients Fig. 6: CPU Load, %
Clients Fig. 7: Network Load
The traffic shown in Figure 7 is taken from the Tvheadend statistic reports and it presents a measurement done at a given time when one to five clients are watching. Channels that are viewed by clients are different. The idea is to show a general presentation of the change in traffic when the number of clients is increasing. All channels are viewed in SD version. 3.2. Comparison between HD and SD channel The difference between the traffic generated when watching HD and SD channel can be seen below. The figures show two clients who watched channels BNT and BNT HD simultaneously. The difference between the traffic generated by BNT and BNT HD in this case is presented schematically in Figure 8:
International Scientific Conference Computer Science’2015
Fig. 8: HD and SD channels
In this case the traffic generated in the HD channel is about 3 times bigger. 4. CONCLUSIONS The study results confirm that the exponential traffic grows with the increase of the users of IPTV service. It could be concludedthat the resulting approximately 1.4 MB/s with only 5 customers would easily become 14 MB/s in real production system. Such load exceeds the resources of most standard 100 Mb/s networks. Generated high traffic makes unicast distribution impracticable in the case of large number of clients. On the other hand, the relatively easy realization and maintenance make unicast distribution a good option for building IPTV in small LANs – e.g. for home use or in a computer lab. Today, the Internet offers basic low video quality and user-generated content through websites like YouTube, which, despite the small size of the video window and the quite vague images, managed to attract millions of viewers. The larger capacity of the optical routes gives rise to the development of IPTV technology, making it a competitor against the traditional broadcast platforms for video content, such as cable and satellite technologies. Such future trends are replacing cable TV in the form it exists today. IPTV will be the most perspective method for the broadcast of media content in near future. Within a few years most people in Bulgaria will be able to watch IPTV anywhere; this platform will be the best way to access media. The reason is that IPTV technology provides many more opportunities and applications in comparison to the modern cable TV. 5. REFERENCES [1] O’ Driscoll, G. (2008) Next Generation IPTV services and Technologies. New Jersey; USA: John Wiley & Sons. [2] ITU-T Newslog (2006) IPTV Standardization on Track Say Industry Experts. [3] Communications Regulation Commission (2009) Resolution №01515/09.06.2009 [4] http://tvheadend.org/ [5] http://www.videolan.org/vlc
