State of the art on video communications Le Tien Anh Telecom and Management Sud Paris.

State of the art on video communicationsState of the art on video communications

Le Tien Anh

Telecom and Management Sud Paris

Agenda

1. Backgrounds of video communicationsA bit of historyApplicationsCodecs

2. Video conferencing service and network architecturesInternational standards for the video conferencing serviceNetwork and Service architectures

3. Worldwide marketBig boysStart-ups

4. Challenges in Viet NamForeign playersHome teams

5. Conclusions

A bit of history

Fig. 1 : Video communication – a bit of history

1920

2009

· 100 telephone lines (each 54 kbps),· Video & Audio separated,· Raw analog video,· 5.25 in. x 4.75 in. video size,· 160$/month.

· VLSI tech. appeared.

Sep 1982The first VTS 1.5 reached the market

1964AT&T introduced “Picturephone” at the World's Fair, New York

1976NEC's world first group oriented video communication system

1924Bell Lab.'s demostrations of video com. between Wasington DC. and New York

1971Ericsson demonstrated the first trans-atlantic video telephone call

· Codecs were sold at $250.000,· Analog video required a transmission speed of at least 45 Mbps,· In 1978, codecs helped to reduce the required bandwidth to 6 Mbps.

· The VTS 1.5 codec required 1xT1 = 24x56 kbps = 1,344 Mbps.

1984A team of MIT’s engineers found PictureTel

· PictureTel’s codec required 4x56 kbps = 224 kbps.· $80.000 per system, $100 per hour,· First software based video conference system.

1989VTEL's first PC-based videoconferencing service

Oct 1996ITU-T standarded H.323 version 1

Oct 1998ISO/IEC standarded MPEG-4 version 1

May 03ITU-T recommendation H.264 advanced video coding (AVC)

2007ITU-T/MPEG recommendation H.264 Scalable video coding (SVC) (VNTelecom2009)

Applications

Video-phony: – Skype®, YIM®, MSN®, Google®…– Mobile video calls over 3G networks.

Video conference:– Business:

• Conferencing among employees, customers, suppliers, and strategic partners.– Governments & Politics:

• In 2004, 4,000 US Democratic delegates joint video conference,• Vietnamese government.

– Emergencies,– Distance learning, distance training,– Telemedicine:

• Patients in military bases or in prisons,• Patients in remote areas with the help of visiting nurses.

– Various desktop videoconferencing applications: Skype®, WengoVisio®,

– Pornography.

Codecs

Video formats:

FormatTotal

Aspect Ratio

Size

SQCIF (Sub QCIF) 16:11 128x96QCIF (Quarter CIF) 4:3 176x144CIF (Common Intermediate Format)

4:3 352x288

4CIF 4:3 704x576 16CIF 4:3 1408x1152SD (Standard Definition) 4:3 704x480

HD (High Definition) 16:9 1280x720 (i or p)

Table 1 : Main video formats

Codecs

Popular video codecs: – MPEG (ISO): MPEG-1, MPEG-2, MPEG-4,

– H series (ITU-T): H.261, H.262, H.264,

– Joint Video Team: H.264 = MPEG-4 part 10 or H.264/Advanced Video Coding.

Frames, Group Of Pictures: – I (intra), P (predicted), B (bi-directional) frames and GOP (Group of Pictures)

– Size{I} = 4xsize{P}; size{P} = 2xsize{B},

– Frame transmitting order: I P B B P B B P B B I B B

– Frame encoding/decoding order: I B B P B B P B B P B B I

– GOP length should be selected well. In the DVD standard, GOP length = 15

Codecs In Nov 2007, Scalable Video Coding (SVC) was added to the H.264/AVC:

– Scalability has been supported from MPEG – 2, however it is rarely been used:

• Significant loss in coding efficiency,

• Large increase in decoder complexity.

– Fully compatible with H.264/AVC,

– Allowing decoders to process only a subset of the stream to produce scalable outputs,

– One encoding / multiple decoding,

– Adaptation to a diversity of networks, terminals...

– Available scalabilities in SVC: Spatial, Temporal, SNR (Quality), or a composition of them.

Fig. 2 : SVC spatial scalability Fig. 3 : SVC scalability

International standards for the video conferencing service

Signaling protocols: - H.323:

• ITU-T call signaling and control, multimedia transport and control, and bandwidth control for point-to-point and multi-point conferences,

• Has been widely implemented by voice and videoconferencing equipment manufacturers,• Support video codecs: H.261, H.263 and H.264.

- SIP (Session Initiation Protocol):• IETF signaling protocol, widely used for setting up and tearing down multimedia

communication sessions such as voice and video calls over the Internet.

Media control and Transport protocols: - RTP (Real-time Transport Protocol):

• Each media stream is transported on a separate RTP connection.

- RTCP (RTP Control Protocol): • Providing periodic reports (statistics, quality of reception, information for synchronizing

audio and video streams).

Network and Service architectures

Network architecture:– MCU (Multipoint Control Unit):

• Transcoding,• Transrating.

– Continous presence: with Multicasting• IP Multicast:

Normally use UDP (1-n), Unreliable Packet Delivery, Packet duplication, Network congestion, MBone

• Application Level Multicast: Immediate implementation on the

Internet, Not mature enough.

Subscriber Station 1





Subscriber Station 2 Subscriber Station 3

MCU Server

Fig. 4 : Multipoint Control Unit





Fig. 5 : Naïve unicast/IP/Application Level Multicast





Network and Service architectures

Service architecture:

– Voice-activated conference:

• Based on the incoming voice energy from participants, the active speaker’s video is sent to all,

• “Image pass through” or “stream switching” mode.

– Continuous Presence conference:

• Displaying two or more participants simultaneously.

– Lecture Mode and Round-Robin conference:

• The lecturer’s sub-picture is locked,

• Students’ sub-pictures operate in a continuous presence mode with voice-activates priority.

Worldwide market

Big boys:

– Cisco®

– Polycom®

– Tandberg®

Start-ups:

– Vidyo®: SVC video conferencing

– Dimdim®: webinar over the web

– WengoVisio®: Video conference over the web

Mobile video phony:

– 3G networks,

– Question: who are capable of answering mobile video calls?

– Cultural block.

Fig. 6 : Cisco’s HD TelePresence

Fig. 7 : Polycom TPX HD 306M

Fig. 8 : Tandberg 1700 MXP 450

Fig. 9 : Mobile video phony

Challenges in Viet Nam

Foreign players:

– Polycom®, Tandberg®…

– Wining business “telepresence” services. Home teams:

– Viettel Technologies® (HD Teleconferencing): Vietnamese government

– Elcom® (eVision): Vietnam Ministry of Defense (Bo Quoc Phong)

– CMC®,

– Teleconferencing services: VTI, VTN:• 2% revenue,

• 10 M VND/3 hours.

– Telemedicine: Viet Duc hospital and VNPT succeeded in tele-operations.

– Winning room conferencing services, virtual office services.

Challenges in Viet Nam

Challenges:– Lack of equipments:

• Hardware codecs must be imported.– System costs,– Lack of network quality (business quality is around 400 kbps),

• ADSL speed in Viet Nam is around 200 kbps.– Lack of static IP:

• Dynamic (local) IPs are usually assigned,• NAT traversal techniques,• Using leased lines with high renting prices and low usability.

– Security:• Governments, military.

– Lack of standardization:• Local video conferencing services are using different codecs and signaling protocols,• Difficulties inter-operating with each other and with foreign systems.

– Cultural block:• Face-to-face meeting habits.

Conclusions

Video communications is the future of human telecommunications,

Standardization is very important in order to open to the world of multimedia

communicators,

Scalable Video Coding is a suitable video codec for a video communication environment

with different bandwidths and variable terminal’s computabilities,

Real-time video codec cards are extremely expensive now in Viet Nam, this is a business

opportunity for hardware producers and assemblers to make money from a raising video

communications industry.

The solution for the expense problem can be “virtual office”.

Q&A

Thank you very much for your attendance!Thank you very much for your attendance!

ReferencesReferences

[1] Video conference: the whole picture.

[2] http://www.sipro.com

[3] Voice and Video Conferencing fundamentals

[4] Scalable Video Coding-Scalable extension of H.264 / AVC-Thompson

[5] http://www.mbone.net/

[6] http://esm.cs.cmu.edu/

[7] http://www.mpegla.com

[8] http://www.cisco.com

[9] http://www.polycom.com/

[10] http://www.tandberg.com/

[11] http://www.elcom.com.vn

[12] http://www.vietteltechnologies.com.vn/en/services.html

[13] http://www.vidyo.com/Conferencing.html

[14]http://chinhphu.vn/portal/page?_pageid=33,128127&_dad=portal&_schema=portal&pers_id=134916&item_id=7818047

http://www.mbone.net/

http://esm.cs.cmu.edu/

http://www.polycom.com/

http://www.tandberg.com/

http://www.vietteltechnologies.com.vn/en/services.html

http://www.vidyo.com/Conferencing.html

State of the art on video communications Le Tien Anh Telecom and Management Sud Paris.

Documents

Transcript of State of the art on video communications Le Tien Anh Telecom and Management Sud Paris.