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IPTV: Becoming a reality. Pierre Thiry CNIT Instructor ICONS P.I. Outline. Cable TV system: Live TV : Radio Frequency channels Video-on-demand: DVB (Digital Video Broadcasting) Definition of IPTV : free and fee-based How fee-based IPTV works: Encoding at the head end:MPEG2 & MPEG4
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IPTV: Becoming a reality Pierre Thiry CNIT Instructor ICONS P.I.
Outline • Cable TV system: • Live TV : Radio Frequency channels • Video-on-demand: DVB (Digital Video Broadcasting) • Definition of IPTV : free and fee-based • How fee-based IPTV works: • Encoding at the head end:MPEG2 & MPEG4 • IP packets • Distribution and Reception: • Live TV: IGMP v2 • Video-on-demand: RTSP • Challenges and present state in the US
How present cable TV works • Live TV needs a tuner to select the proper channel • Video on demand uses the Digital Video Broadcast (DVB) protocol • Cable TV uses fiber-optic cable to transmit to the neigborhood and use coaxial cable to connect to the home
Definition of IPTV: Free IPTV • Free IPTV: according to Wikipedia, as of June 2006, there are over 1,300 free IPTV channels available. • All you need is an Internet connection and a PC, an iPOD or a 3Gcell phone with the proper streaming software • Most TV stations have now a Free IPTV web site
Video Compression formats: MPEG-1 (Video CDs) progressive Data rates were limited to 1.8 Mbps (1996) (MP3 is the audio encoding of MPEG-1) MPEG-2 (DVD, Digital TV) interlaced Data rates are from 1.5 to 60 Mbps (2000) Two container formats: • Transport Stream: for broadcasting (ASTC & DVB) • Program Stream: for DVD abd Super Video CD
Video Compression formats: MPEG-4 (All Inclusive and Interactive) based on Quicktime, including low-bandwidth formats for transmitting to wireless devices as well as high-bandwidth for studio processing . MPEG-4 AAC (advanced audio coding) is widely used as an audio-only format (replaces MP3) MPEG-4 AVC (or H.264) is the new standard for video transmission.
Distribution & Reception • Multicast protocol: from national headend to the local office: needs powerful routers • Bottleneck at the local office: • DSL is limited in bandwidth (up to 3Mbps) • The new ADSL+ will go up to 25Mbps • Solution: use IGMP v2 from the set-top box to ask for a given channel. The set-top box is an IP receiver.
Quality of Service • Between the headend and the local office: Error correction mesures for the multicast streams • Between the local office and the set-top box: since it is unicast , it is not a problem, the system can request a resend of lost packets.
IPTV Video-on-demand • Real Time Streaming Protocol enables DVD-style control (pause, fast forward..) over a multimedia stream. • Limit on the number of simultaneous channels: • For SDTV maximum of 10 channels • For HDTV maximum of 2 channels if MPEG-2 is used. More if MPEG-4 is used. • Advantage of the fiber to the home.
Example of IPTV abroad • Hong Kong and China: PCCW http://en.wikipedia.org/wiki/Pacific_Century_Cyberworks http://www.nowbroadbandtv.com/eng/ More than 300,000 subscribers
In the US: AT&T and Verizon • AT&T – project Lightspeed : 40,000 mile rollout of fiber. Not all the way to the home. ( limited by ADSL performance 3Mbps) • Verizon offer 300+ channels of TV over Fiber to the home ( 4.5 Gbps – 3.5 Gbps for TV )
Telco vs Cable • Telco have won recently a battle from the FCC to allow franchise agreements to be negotiated by state. • If Telco companies can compete with the cable that will mean cheaper services for the customer. • Cable companies are looking also at IP to upgrade their services.