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State of the art on video communications
Le Tien Anh
Telecom and Management Sud Paris
Agenda
1. Backgrounds of video communications

A bit of history

Applications

Codecs
2. Video conferencing service and network architectures

International standards for the video conferencing service

Network and Service architectures
3. Worldwide market

Big boys

Start-ups
4. Challenges in Viet Nam

Foreign players

Home teams
5. Conclusions
Page  2
A bit of history
2007
ITU-T/MPEG recommendation H.264 Scalable video coding (SVC)
May 03
ITU-T recommendation H.264 advanced video coding (AVC)
Oct 1998
ISO/IEC standarded MPEG-4 version 1
Oct 1996
ITU-T standarded H.323 version 1
1989
VTEL's first PC-based videoconferencing service
1984
A team of MIT’s engineers found PictureTel
Sep 1982
The first VTS 1.5 reached the market
1976
NEC's world first group oriented video communication system
2009 (VNTelecom2009)
·
·
·
·
PictureTel’s codec required 4x56 kbps = 224 kbps.
$80.000 per system, $100 per hour,
First software based video conference system.
The VTS 1.5 codec required 1xT1 = 24x56 kbps = 1,344 Mbps.
·
VLSI tech. appeared.
·
·
·
Codecs were sold at $250.000,
Analog video required a transmission speed of at least 45 Mbps,
In 1978, codecs helped to reduce the required bandwidth to 6 Mbps.
·
·
·
·
·
100 telephone lines (each 54 kbps),
Video & Audio separated,
Raw analog video,
5.25 in. x 4.75 in. video size,
160$/month.
1971
Ericsson demonstrated the first trans-atlantic video telephone call
1964
AT&T introduced “Picturephone” at the World's Fair, New York
Fig. 1 : Video communication – a bit of history
Page  3
1924
Bell Lab.'s demostrations of video com. between Wasington DC. and New York
1920
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.
Page  4
Codecs

Video formats:
Format
Total Aspect Ratio
Size
SQCIF (Sub QCIF)
16:11
128x96
QCIF (Quarter CIF)
4:3
176x144
CIF (Common Intermediate Format)
4:3
352x288
4CIF
4:3
704x576
16CIF
4:3
1408x1152
SD (Standard Definition)
4:3
704x480
HD (High Definition)
16:9
1280x720 (i or p)
Table 1 : Main video formats
Page  5
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:
IPBBPBBPBBIBB
– Frame encoding/decoding order:
IBBPBBPBBPBBI
– GOP length should be selected well. In the DVD standard, GOP length = 15
Page  6
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.
Page  7
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):
•
Page  8
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
Subscriber Station 1
MCU Server
Subscriber Station 2
Subscriber Station 3
Fig. 4 : Multipoint Control Unit
SubscriberStation
Station111
Subscriber
Subscriber
Station
Subscriber Station 3
• Application Level Multicast:


Page  9
Immediate implementation on the
Internet,
Not mature enough.
Subscriber
Station
SubscriberStation
Station222
Subscriber
Subscriber Station
Subscriber
Station 44
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 voiceactivates priority.
Page  10
Worldwide market

Big boys:
– Cisco®
– Polycom®
– Tandberg®

Start-ups:
Fig. 6 : Cisco’s HD TelePresence
Fig. 9 : Mobile video phony
– Vidyo®: SVC video conferencing
– Dimdim®: webinar over the web
– WengoVisio®: Video conference over the web

Mobile video phony:
– 3G networks,
Fig. 7 : Polycom TPX HD 306M
– Question: who are capable of answering mobile video calls?
– Cultural block.
Page  11
Fig. 8 : Tandberg 1700 MXP 450
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.
Page  12
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.
Page  13
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”.
Page  14
Q&A
Thank you very much for your attendance!
Page  15
References
[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