Video on Demand over the Internet Trends and challenges

1. Video on Demand over the InternetTrends and challenges Juergen Ehrensberger (HEIG-VD) Andrés Revuelta (EIG) Jean-Roland Schuler (EIA-FR) November 2006

2. Project Vadese « Video on Demand and Security » http://www.vadese.org • Two-years research project • 4 research groups from 3 different schools(Fribourg, Geneva, Yverdon) • Focuses on the needs of VoD services providers • Quality of Service • Patching over Peer-to-peer • Digital Rights Management

3. Video over the Internet 31 October 2006:Swisscom launches Bluewin TV

4. Video over the Internet July 2006:Deutsche Telekom launches IPTV

5. Video over Internet – Market studies IPTV « Television broadcast over the Internet access » • Worldwide market size (Gartner 2006) • $870 million in 2006 • $13 billion in 2010 Video on Demand « Download or streaming of movies at any time » • Worldwide market size (iSuppli 2006) • 40% growth in 2005 • $2 billion in 2006 • $13 billion in 2010

6. Another market study...

7. Media distribution over the Internet Media can be transferred by download or streaming Download • A file is downloaded from a server to the customer’s equipment • The media can be consumed only after the download has finished • Simple • Not suited for live content • Long waiting time Streaming • A continuous media flow of packets is transferred from a server to the customer • The customer consumes the media simultaneously with the transfer • Suited for live content • Technically challenging

8. Network scenario

9. Quality of Service • The main challenge of streaming media over this Internet is to obtain a sufficient Quality of Service : « QoS is the collective effect of service performance which determines the degree of satisfaction of a user of a service » (ITU-T Rec. E-800)

10. Measurable performance parameters Throughput • ‘Speed’ of the transmission, bits per second received Packet loss rate • Percentage of packets lost inside the network Network delay • Delay between the sending of a packet at the source and the reception by the receiver Delay variation • Changes of network delay between successive packets

11. Throughput • Media streams have an inherent bitrate that has to be provided by the network Throughput requirements Transmission capacity

12. Packet loss • What happens if there is too much traffic in the network? • The Internet is a network of transmission links, connected to routers

13. Packet loss • What happens if there is too much traffic in the network? • Each router receives traffic from several input links and forwards the packet to output links

14. Packet loss • What happens if there is too much traffic in the network? • If the output link is occupied, packets have to wait for transmission in a queue

15. Packet loss • Transmission queues on routers are causing packet loss and delays Measurement over low-capacity access links • Up to 5% packet loss • 20ms one-way delay

16. Example: 1% loss MPEG-2 No error concealment Example: 5% loss MPEG-2 No error concealment Effect of packet loss on video quality

17. Effect of network delay • Network delay is not critical for non-interactive applications • Typically network delay is below 1 seconds • User may tolerate several seconds of delay Possible problems • « Roberto Baggio Effect » • Channel switching delay

18. Delay variation • Media playback requires a constant flow of data • The packets of the media flow experience different network delays • A playout buffer compensates the delay variations • Half-filled upon start of the transmission (« Buffering... ») • Increases network delay • Delay variations should be small to keep playout buffer small

19. Current challenges Insufficient QoS over ADSL and CaTV • Overdimensioning or VDSL • QoS mechanisms in the ISP network • QoS mechanisms on user’s Set-Top Box High cost for streaming individual flows • « Patching » of video flows • Peer-to-peer distribution of flows Digital Rights Management

20. Overdimensioning of the access link • ADSL link with 3 Mb/s • MPEG-4 AVC video with TV quality at 768 kb/s • Additional traffic (Web, E-mail, downloads) may deteriorate the video quality Dynamic overdimensioning • ISP dynamically increases ADSL capacity during video streaming • Should provide sufficient capacity for video and additional downloads Problem: traffic demand adapts to available capacity Very High Bitrate DSL (VDSL2) • Provides capacity of 20 Mb/s (over 1500m) • Allows simultaneous transmission of 2 HDTV channels • Problem: high investment required to upgrade the access network

21. QoS mechanisms in the ISP network • Even over ADSL, a sufficient QoS can be provided using QoS mechanisms • Idea: give video flow priority over other traffic • Video flow gets sufficient capacity to avoid packet loss on the ADSL link • Other traffic (Web, download) is still possible, but slower

22. QoS mechanisms in the ISP network • Even over ADSL, a sufficient QoS can be provided using QoS mechanisms • Idea: give video flow priority over other traffic • Video flow gets sufficient capacity to avoid packet loss on the ADSL link • Other traffic (Web, download) is still possible, but slower

23. QoS mechanisms on user’s Set-Top Box • Solution developed in Vadese • Modifications of the access network are costly • Service providers do not own the access network • How can a service provider offer sufficient QoS? • Use QoS mechanisms on the Set-Top Box • Has to control traffic after it has crossed the ADSL link!

24. QoS mechanisms on user’s Set-Top Box • Non-video traffic mainly uses TCP • TCP adapts to network congestion, detected by packet loss • Control queue length on ISP router from Set-Top Box • « Split » Advanced Queue Management

25. High cost for Video-on-Demand • In VoD, customers access videos at different moments • The simple approach to start a new flow for each user is not economical • Example : access link at 1 Gb/s • Only 200 simultaneous HDTV flows (at 5 Mb/s) • Cost of $1 per video, only for transmission

26. Near Video-on-Demand with Multicast • Solution • A new flow for the same video starts every n minutes • Similar to a TV broadcast that repeats every n minutes • Flow is efficiently transmitted via multicast • Multicast is only feasible for network operators

27. Video patching with Peer-to-peer • Solution developed in Vadese • Allows true Video-on-Demand • Can be used by service providers without their own multicast network • Idea of patching: • A customer who already receives a video can relay the flow to a new customer • The missing part of the video is temporarily ‘patched’ from the server

28. True Video-on-Demand with Multicast • Possible alternative to Peer-to-peer transmission • Combines Multicast and Patching to achieve true Video-on-Demand • Solution • A new multicast flow for the same video starts every n minutes • When a new customer arrives, it joins an existing multicast session • The missing first minutes of the movie is patched by a short-lived patching flow

29. Conclusion Project Vadese - Video on Demand and Security • Focuses on the needs of VoD services providers • Quality of Service • Patching over P2P • Digital Rights Management • Technologies will be integrated in a Set-Top Box • Possible valorizations • Follow-up projects with commercial partners • Intellectual property • Commercialization of some of the technologies