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

Project Vadese « Video on Demand and Security » 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

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

Video over the Internet July 2006: Deutsche Telekom launches IPTV

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

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Media distribution over the Internet Media can be transferred by download or streaming Download –A file is downloaded from a server to the customers 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

Network scenario

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)

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

Throughput Media streams have an inherent bitrate that has to be provided by the network Throughput requirements Transmission capacity CodecQualityBitrate MPEG-2TV quality1 – 4 Mb/s MPEG-4 AVCTV quality768 kb/s MPEG-4 AVCHDTV5 – 6 Mb/s NetworkCapacityMPEG-4 TV flows ADSL3 Mb/s4 flows Ethernet100 Mb/s130 flows ISPs / Internet10 Gb/s13000 flows

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

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

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

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

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

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

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

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

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, , 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

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

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

QoS mechanisms on users 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!

QoS mechanisms on users 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

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

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

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

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

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