Video Communication System

SONY PCS-1 SONY PCS-1P

SONY PCS-1 FEATURES
Sony PCS-1 Data-Sharing Capabilities
Share presentation documents originated from your PC and hand-written content on a whiteboard within an audio- and video-based conference as if all meeting participants were in the same room. The PCS-1/1P provides two major capabilities to achieve this benefit:
Sharing Presentation Documents in XGA Resolution
Connecting an optional PCS-DSB1 Data Solution Box and the PCS-1/1P can transfer screen shots in XGA resolution from your PC to remote sites through a network or an ISDN line. This allows you to share presentation documents created in software applications such as Microsoft PowerPoint, Microsoft Excel, and Microsoft Word, as well as other still images on your PC screen with your videoconferencing counterparts. Up to two PCs can be connected to a PCS-DSB1 for faster transition between presenters, and with the touch of a button, screen shots from the selected PC can easily be transmitted. You can choose to view the screen shots with a single monitor in Picture in Picture mode*, or using a second monitor in Full-screen mode.
* In Picture in Picture mode with a single monitor, screen shots are displayed in the main screen area, while video is displayed in a small window positioned at the corner.
PCS-1 New and Powerful Method of Communication
Incorporating the most advanced IT and worldwide-proven AV technologies into a compact and stylish two-piece body, the Sony PCS-1/1P Video Communication System offers a new and powerful method of communication. Its ideal for holding meetings, with free and dynamic exchange of ideas and opinions no matter how far away from each other they are located. The Sony PCS-1/1P provides effective data-sharing capabilities, which significantly enhance the benefits offered by conventional audioand video-based conferencing. In addition, it brings superb acoustic quality which has won critical acclaim from the audio conference market into videoconferencing applications for more natural sound clarity.
Digital Whiteboard Function Support
Using a digital whiteboard recorder*, notes and drawings on a whiteboard can be electronically converted and then transferred in real time to remote sites to be displayed on a screen. In addition, notes and drawings can be captured by the SnapShot mode, saved in a JPEG file, and recorded to Memory StickTM media attached to the PCS-1/1P exceptionally useful for later viewing and The Sony PCS-1/1P can provide major improvements in the way your distribution purposes.
organization communicates, allowing you to engage in simple, immediate, and face-to-face communication with your staff, or to make critical project decisions.
* Digital whiteboard recorders are available from other manufacturers. For recommended models, please contact your local Sony office.
Sony PCS-1 Flexible Installation
The PCS-1/1P comprises the Camera Unit and Communication Terminal (Main unit). This unique two-piece design provides the flexibility to meet various installation needs. Integrated with the optional PCS-STG1 or PCS-STP1 Camera Stand, its compact and stylish configuration provides the convenience of using a projector and FPD (Flat Panel Display) together, making a great impression on conference participants. Its small size of 147 (W) x 130 (H) x 138 (D) mm and light weight of 1.1 kg allows the Camera Unit to be easily installed in spacecritical environments. Positioned on top of the Communication Terminal, the combined unit provides a footprint of just 258 (W) x 171 (D) mm small enough to sit on top of any TV monitor.

Sony PCS-1 Multi-point Videoconferencing
Using optional MCU (Multi-point Control Unit) Software, a multipoint videoconference comprising up to six sites can be set up. The PCS-323M1 H.323 MCU Software enables a multi-point videoconference compliant with the ITU-T H.323 standard, while the PCS-320M1 H.320 MCU Software enables a multi-point videoconference compliant with the ITU-T H.320 standard, and also accepts audio-only connections by telephone. These configurations also offer data-sharing capabilities. When a multipoint videoconference for seven to ten sites is required, two PCS1/1P units with PCS-323M1 H.323 MCU Software installed can be cascaded.* These two units can then be connected to further four systems each, resulting in up to ten systems being connected and controlled simultaneously.
* Data-sharing capabilities are not available in this configuration.
Sony PCS-1 Outstanding Audio Quality
To communicate clearly and effectively in a meeting, audio is an indispensable factor. Sony audio technology, which has been leading the audio conference market for so long, now makes videoconference audio even more natural and crisp:
Sony PCS-1 Memory Stick Support
Attaching Memory Stick media to the PCS-1/1P allows presentation documents and digital photos to be displayed in 4CIF format without connecting to a PC. The graphics displayed can also be transferred to remote sites for data-sharing purposes. In addition, an address book and system settings can be saved and edited in the Memory Stick media.
Super Acoustic System Support
The optional CTE-600 Communication Transducer is an acoustic system that comprises six radially arranged uni-directional microphones and one omni-directional speaker. Each microphone constantly detects the audio level in the conference room; however, only the microphone that detects the largest audio level sends a signal to the PCS-1/1P. What this means is that the active speakers voice is clearly transmitted, while minimizing background noise. The speaker system is designed such that sound is projected horizontally in all directions, for clear sound quality in meetings involving as many as 15 to 20 participants.

MPEG-4 Audio Encoding

The PCS-1/1P features AAC (Advanced Audio Coding) at 14 kHz, compliant with the MPEG-4 standard. It emits superb audio quality for a point-to-point videoconference via a network, with double the bandwidth frequency of conventional audio encoding.
Sony PCS-1 Excellent Video Quality
The PCS-1/1P is equipped with encoding capabilities compliant with the ITU-T H.323 standard for network-based videoconferencing at up to 2 Mb/s and 30 frames/s. With connection to an optional PCS-B768 ISDN Unit, it is possible to hold a videoconference compliant with the ITU-T H.320 standard at up to 768 kb/s via an ISDN line.
QoS (Quality of Service) Enhancement Functions

When holding a videoconference via a network, a common concern is how to maintain picture quality in varying levels of performance. The PCS-1/1P provides two advanced functions to enhance a QoS on the network:

Adaptive Rate Control

The adaptive rate control function varies the bit rate of A/V data corresponding to changing network conditions and selects the most appropriate frame rates. When network traffic becomes congested, it automatically lowers the video bit rate, and when the network condition recovers, it raises the bit rate up to the initial value. This function can help prevent the picture quality from being degraded.
ARQ (Auto Repeat reQuest)
The ARQ function recovers lost packets by resending the same packets, buffered in the encoder, which helps to avoid a picture collapse.
SONY PCS-1 OPTIONAL ACCESSORIES

PCS-DSB1

Data Solution Box
Dimensions: 240 (W) x 33 (H) x 160 (D) mm Mass: 0.85 kg

PCS-STG1

Camera Stand
Dimensions: 386 (W) x 1170 (H) x 386 (D) mm Mass: 17.5 kg

PCS-STP1

Dimensions: 386 (W) x 1170 (H) x 386 (D) mm Mass: 13.0 kg

CTE-600

Communication Transducer
Dimensions: f 248 x 104 (H) mm Mass: 1.5 kg

PCS-B768

ISDN Unit
Dimensions: 165 (W) x 34 (H) x 127 (D) mm Mass: 0.40 kg

PCS-323M1

H.323 MCU Software

PCS-320M1

H.320 MCU Software

PCS-A1

Microphone
Dimensions: f 74 x 16 (H) mm Mass: 0.17 kg

PCS-DS150/DS150P

Document Stand
Dimensions: 120 (W) x 480 (H) x 380 (D) mm Mass: 2.6 kg

EVI-D100/D100P

Communication Color Video Camera
Dimensions: 113 (W) x 120 (H) x 132 (D) mm Mass: 0.86 kg
SONY PCS-1 SYSTEM CONFIGURATION EXAMPLES
A videoconference via a network using a single projector or flat panel display in Picture in Picture mode

Ethernet

Intranet / Internet VPN

PCS-1/1P

Digital whiteboard

Memory Stick

RGB RGB

Projector

Note PC
A videoconference via an ISDN line using a projector and either a flat panel display or TV monitor
Composite/ S-video IR/ S-video S-video

EVI-D100/ D100P

Composite/ S-video TV monitor

Audio RGB

Note PC Note PC Note PC PCS-A1 x 5
SONY PCS-1 SPECIFICATIONS
Video Signal system Standards Resolution Frame rate Bit rate Audio Bandwidth and coding Remote Commander PCS-1: NTSC PCS-1P: PAL H.261, H.263, H.263+, H.263++, MPEG-4 SP@L3 QCIF, CIF Max. 30 frames/s Up to 768 kb/s in H.320 (Incl. audio) Up to 2 Mb/s in H.323 (Incl. audio) G.711: 3.4 kHz at 56/64 kb/s G.722: 7.0 kHz at 48/56/64 kb/s G.722.1: 7.0 kHz at 24 kb/s (H.323) G.728: 3.4 kHz at 16 kb/s G.723.1: 3.4 kHz at 5.3/6.3 kb/s (H.323) G.729: 3.4 kHz at 8 kb/s (H.323) MPEG-4 AAC mono 14 kHz at 64 and 96 kb/s (H.323) Reduction rate: 30 dB Echo path length: 340 ms (4 kHz and below) 110 ms (4 to 8 kHz) 56 ms (8 kHz and above) Noise suppressor included Automatic gain control included XGA: 1024 pixels x 768 lines (H.263) 4CIF: 704 pixels x 576 lines (H.261 Annex D and H.263 Base) Picture in Picture Sub screen size: 1/9 (One of four corners) ITU-T Standards H.320, H.323 H.221 Bonding H.281 FECC H.225.0 H.245 T.120 Network Protocols TELNET (Server) HTTP (Server) FTP (Server) SNMP (Agent) PING DNS (Client) DHCP (Client) RTCP RTP TCP ARP NTP (Client) Multipoint Capabilities Up to 6 sites (H.323) Up to 10 sites (H323)* Up to 6 sites (H.320) Lip Synchronization Manual On/Off Camera Unit Image sensor Horizontal resolution Focal length Focus IRIS Horizontal view angle Zoom ratio Pan angle Tilt angle Preset S/N Others 1/4 type CCD PCS-1: 470 TV lines PCS-1P: 460 TV lines 3.1 to 31 mm (F1.8 to 2.9) Auto/Manual Auto 6.6 to 65 degrees x10 (Optical zoom), x40 (Digital zoom) -100 to +100 degrees (Max. 300 degrees/s) -25 to +25 degrees (Max. 125 degrees/s) Up to 6 positions More than 50 dB Back light shooting I/F of PCS-B768 ISDN: BRI (Basic Rate Interface) x 6 Environment Operating temperature 5 C to 35 C Operating humidity 30% to 70% Storage temperature -20 C to +55 C Storage humidity 25% to 75% Power Requirement and Consumption Requirement PCS-1: AC 120 V, 50/60 Hz PCS-1P: AC 220 V to 240 V, 50/60 Hz Consumption DC 19.5 V, 3.5 A Dimensions and Weight Communication Terminal 258 (W) x 54 (H) x 171 (D) mm, 1.3 kg Camera Unit 147 (W) x 130 (H) x 138 (D) mm, 1.1 kg Remote Commander 50 (W) x 24 (H) x 197 (D) mm, 0.14 kg (Incl. battery) System Components and Supplied Accessories Communication Terminal x 1 Camera Unit x 1 Remote Commander x 1 Camera Cable (0.25 m) x 1 AC Adaptor x 1 IR Repeater x 2 Manganese Battery for Remote Commander x 2 Velcro for Communication Terminal x 2 Double-faced Tape for Camera Unit x 3 Audio Cable (1.0 m) x 1 S-Video Cable (1.5 m) x 1 Operation Manual x 1 (Japanese, English, French, Spanish, Italian, German, Simplified Chinese) Warranty Card x 1 * Two PCS-1/1P units with PCS-323M1 installed must be used. Graphics Format: Wireless SIRCS I/F of PCS-1/1P Video S-video input x 1 Composite input x 1 S-video output x 2 Composite output x 1 RGB output x 1 IR for PCS-DS150/DS150P x 1 Line input (RCA) x 1 External microphone input (Plug in power) x 2 Line output (RCA) x 2 Internal microphone x 1 RGB (XGA) output x 1 10Base-T/100Base-TX x 1 Dedicated connector x 1 Memory Stick slot x 1 RS-232C/VISCA (Mini-DIN 8-pin) for second camera x 1 SIRCS IR output for TV monitor x 2 IR for Remote Commander x 1 Microphone input (Mini jack) x 5 Line output (Mini jack) to active speaker x 1 AUX input (RCA) x 1 AUX output (RCA) x 1 RGB (XGA, SVGA, VGA) input x 2 RGB (XGA) output x 1

Echo cancellation

Graphics Network Digital whiteboard Memory Stick Control
I/F of PCS-DSB1 Audio I/F

Graphics

IVCi 180 Adams Avenue, Hauppauge, NY 11788 1-800-224-7083 www.ivci.com

VC-0104

2003 Sony Electronics Inc. All rights reserved. Reproduction in whole or in part without written permission is prohibited. Features and specifications are subject to change without notice. All non-metric weights and measures are approximate. Sony and Memory Stick are trademarks of Sony. Microsoft and PowerPoint are registered trademarks of Microsoft Corporation.

Printed in USA 7/03

W H I T E

P A P E R

CORE TECHNOLOGIES OF SONYS PCS-1 VIDEOCONFERENCING SYSTEM
and the exorbitant price of the equipment hindered its wide acceptance. The high tariff on circuit-switched lines created another bottleneck to the acceptance process. Videoconferencing systems were used only in

Table of Contents

1. 2. 3. 3.1. INTRODUCTION PRODUCT FEATURES CORE TECHNOLOGIES QoS 3.1.1. 3.1.2. Network level QoS Real-time ARQ (Automatic Repeat request) Adaptive Rate Control 4
wealthy organizations and in schools and until the end of the 90s they were not considered to be popular or user-friendly. The recent rapid progress in IC technology has changed this situation. Most significantly, it has enabled dramatic cost reductions in videoconferencing equipment. Moreover, the penetration of broadband IP networks has enabled a cost-effective IP-based
videoconferencing infrastructure. Sonys new IP-based videoconferencing system PCS-1 encompasses the emerging IP-based broadband network infrastructure and provides a highly reliable, cost-effective videoconferencing environment for corporate users, educators, teleworkers, and others. The system provides not only a conventional audio and videoconferencing environment, but also a collaboration environment that enables data sharing of RGB images output from a PC as well as white board images. This paper first illustrates the features of the new PCS-1 Videoconferencing System. Some of the highlights of the PCS-1s attributes are introduced in Chapter 2. The key features of the system QoS, MCU function, advanced video and audio coding technology, whiteboard function, security, PPPoE, and dual video streaming are

3.1.3. 3.2. 3.3.

Internal MCU Function Advanced Video and Audio Coding Technology 3.3.1 3.3.2. H.264 (MPEG-4 AVC) MPEG-4 AAC Wideband Audio Interlace Video MPEG-4 Video
3.3.3. 3.3.4 3.4. 3.5. 3.6. 3.7.
Whiteboard Function Security PPPoE Dual Video Stream

Introduction

Videoconferencing has a surprisingly long history. Experimental analogue-video-based systems were developed decades ago. The first commercial system based on digital technology, using digital- circuit-switched networks, was put on the market in the early 1980s. However the poor quality of video and audio
described in detail in Chapter 3.

Product features

The PCS-1 is a feature-rich, high-performance videoconferencing system available at a very affordable price, developed to address a variety of demands in the conferencing market. Having incorporated advanced AV and IT technologies into its compact B5-footprint body, the PCS-1 can address not only small-to-large-group conferencing applications but also distance education, telemedicine applications, and much more. The PCS-1 will bring a new level of participant interaction, creativity, and productivity to videoconferencing communication. Listed below are just some of the highlights of the PCS-1 features.

Free-Layout Design

remote sites for onscreen display. This is a unique feature of the PCS-1 and is described in detail in Chapter 3.
Superb Video Quality High-Speed Connection
Responding to the proliferation of broadband IP networks, the PCS-1 can achieve up to 2Mbps at a 30 fps IP connection, bringing superb video quality to videoconferencing. Using the PCS-B768, an optional ISDN unit, the PCS-1 can maintain videoconferencing at up to 768Kbps via an ISDN line.

Advanced Video Coding

MPEG-4, H.264, and interlaced SIF are supported The PCS-1 is the first in the industry to support MPEG-4 Video as standard. MPEG-4 capability provides the potential for connection with a variety of consumer video communication devices in the future. H.264, the newly ratified standard, is capable of providing the same picture quality on half the bandwidth. For instance, a video conference call placed using a bit rate of 384Kbps can now deliver the same picture quality of a 768Kbps bit rate call. Network congestion problems and bandwidth limitations can also be overcome due to the lower bandwidth demand of H.264 coding. Interlaced SIF video coding operates at 60 fields per second rather than coding and decoding 30 frames of video per second, resulting in smoother, more life-like images. Interlaced video coding is enabled at bit rates higher than 512Kbps on H.323 calls in motion priority mode.

Superb Audio Quality

One of the innovations that distinguish the PCS-1 from other systems is its compact two-piece design. The unit consists of a codec and a separate camera. This free layout enables the PCS-1 not only to sit on top of a conventional TV monitor but also to function alongside a flat panel display, such as a plasma or projector screen. Installed on a camera stand (PCS-STP1 and PCS-STG1), the PCS-1 can be located just beside the flat panel display or projector screen easily and without restrictions. With the PCS-1s flexibility of installation, videoconferencing is no longer limited to a dedicated room with a TV monitor, but instead can be extended to executive offices with plasma displays or any meeting space or desk with a projector or LCD monitor.

Data Sharing PC Desktop Sharing
The ability to share presentation data from applications like Microsoft Power Point, Excel, and Word has became a very important element of videoconferencing. In response to this demand, the PCS-DSB1 (Data Solution Box), a separate optional device, was developed. In conjunction with PCS-DSB1, the PCS-1 is able to transmit a PC desktop image in XGA resolution to PCS-1s at the far ends so that remote participants can view the presentation material in real time with the original resolution.

Digital Whiteboard I/F

The PCS-1 supports MPEG-4 AAC. With this audio codec, the PCS-1 is able to transfer 14 kHz wideband audio, which is double the bandwidth of conventional videoconferencing audio. This wideband audio raises clarity of sound to a new level and greatly facilitates recognition of the speakers voice. The details are described in Chapter 3.
Other types of data to be shared in videoconferencing are notes and drawings on the whiteboard. To meet this demand, the PCS-1 is equipped with direct I/F for the Mimio XiTM digital whiteboard recorder from Virtual Ink Corporation. Using Mimio Xi, notes and drawings on a conventional whiteboard can be electronically converted and then transferred in real time to

Enhanced Internal MCU

The PCS-1 supports high-performance internal MCU as an option. Videoconferences among up to 6 sites can be held using IP or ISDN connections with PCS-323M1 and H.323 MCU software respectively. In this internal MCU operation, a 4-way or 6-way split-display mode is available depending upon the number of sites. In addition both H.320 (ISDN) and H.323 (IP) calls can be connected on a single multi-point conference call if both PCS-323M1 and PCS-320M1 are installed. In most cases, this increased flexibility eliminates the need for an outside bridging company or additional expensive network hardware when deploying mixed-network multi-point videoconferencing. By cascading two systems with H.323 MCU software, up to 10 sites can be connected on a multi-point call. The details are described in Chapter 3.

Enhanced QoS

far-side can be captured in the SnapShot mode, saved in a JPEG file, and recorded to Memory Stick media inserted in the PCS-1 codec unit. Additionally, pre-recorded images saved on Memory Stick media can be displayed in 4CIF format and transferred during the call.

Core Technologies

3.1. QoS
On the current Internet, an estimated 5 % of packets are lost. Packet loss causes video frame freeze, error propagation, and audio glitches in videoconferencing sessions. The QoS (Quality of Service) and packet loss compensation features are very important when videoconferencing in less than optimal best-effort IP network environments. The main objective of QoS features used in conventional videoconferencing endpoints is to conceal the error. For example, certain technology is used to shuffle image data for transmission so that packet loss does not destroy wide areas of the video image. Other technology is used to increase intra macroblocks requiring no previous frame information, so that the packet loss error does not propagate over a long period, but the increased amount of intra macroblocks requires more bits to carry video frames, resulting in a lower frame rate. Sony has developed new QoS features using a different approach. Sonys approach is to recover the error not to conceal it thereby maintaining the quality of real-time communication. With Sony PCS-1 QoS features, users need not be concerned about bandwidth and network quality; the PCS-1 automatically adjusts its bandwidth, buffering size, and algorithm to maintain high-quality conferencing. The following two major functions are implemented on the PCS-1 to provide the above-mentioned features: Real-time ARQ (Automatic Repeat reQuest) ARC (Adaptive Rate Control) First Network level QoS, IP Precedence, Type of Service, and Differentiated Services are briefly introduced; these are commonly used to deliver high-quality video and audio service over IP networks and are adopted in PCS-1. The details of the newly developed functions are covered in the following sections.

The QoS, Quality of Service, is one of the key issues in IP-based videoconferencing. In order to address the needs for QoS enhancement, the PCS-1 adopts not only Network-level QoS, IP Precedence, Type of service, and DiffServ, which are commonly used to deliver high-quality video and audio services over IP networks, but also two advanced technologies, ARC (Adaptive Rate Control) and Real-time ARQ (Auto Repeat reQuest). ARC is used to adjust the data rate in response to network conditions. ARQ is used for packet loss recovery. By employing the optimal algorithm that provides the best combination of the two technologies, the PCS-1 is able to maintain the picture and sound quality in varying network conditions. The details are described in Chapter 3.

Private Phonebook

The phonebook stored in the PCS-1 is a common one for all users of the PCS-1. For convenience and improved functionality, private phonebook listings can be created and maintained on a Memory Stick. When the Memory Stick is inserted, the PCS-1 automatically recognizes the private phone book as the primary one, thereby eliminating the need for menu adjustments. As an added convenience, one of the video phone numbers can be registered for auto-transmission so that when the Memory Stick is inserted into the PCS-1 unit, the call is executed instantaneously.

Memory Stick Support

The PCS-1 is equipped with an M/S (Memory Stick) slot on the codec unit. Notes and drawings or any image displayed on the screen either near- or

3.1.1. Network level QoS

The PCS-1 can enter the values of IP Precedence, Type of Service, and Differentiated Services. The TOS (Type of Service) field in IP header is used for either defining IP Precedence and Type of Service, or DSCP (Differentiated Services Code Point) bits of Differentiated Services. The usage of the field for either service is up to the service administrator of the network. IP Precedence and Type of Service
Precedence Delay 4 Throughput 7 CU Reliability Minimum Cost CU: Currently Unused
Unless the value of this field is set by the administrator, the default values of this field are all 0. Differentiated Services The Differentiated Services (Diffserv) architecture is based on a network model implemented over a complete Autonomous System (AS) or domain. By putting this domain under administrative control, it is possible to establish clear and consistent rules to manage traffic entering and flowing through the networks that conform the domain. Diffserve defines a field in the IP header called the Differentiated Services Code Point (DSCP), which is a six-bit field as shown below.

0 DSDSDSDSDSDSCU 7 CU

The value of IP Precedence and Type of Service can be defined in Setup menu. IP Precedence bits The IP precedence bits indicates the priority with which a packet is handled as follows: 1 : Network control 0 : Internetwork control 1 : Critical 0 : Flash Override 1 : Immediate 0 : Priority 1 : Routine Delay bit Used when the time it takes for a datagram to travel from the source PCS-1 to the destination PCS-1 or host (latency) is most important. A network provider is requested to select a route with the minimum delay when this bit is set to on. Throughput bit Used when the volume of data transmitted in any period of time is important. A network provider is requested to select a route producing the maximum throughput when this bit is set to on. Reliability bit Used when it is important to be certain that the data will arrive at the destination without requiring retransmission. A network provider is requested to select a route with maximum reliability when this bit is set to on. Minimum cost bit Used when minimizing the cost of data transmission is important. A network provider is requested to have datagrams routed via the lower-cost route when this bit is set to on.

CU: Currently Unused

Type of service field of the IP header is used to define DSCP Hosts in a network that supports. DiffServe make each packet with a DSCP value. Routers within the DiffServe network use these values to classify the traffic into distinct service classes according to DSCP value. Thus, Routers control packets not on a flow-by-flow basis but by traffic classes based on DSCP marking. Because the routers are not required to maintain any elaborate state information to identify the flows, the routers can handle a large number of flows. PHB (Per Hop Behavior) is defined according to the traffic classes based on DSCP marking. For example, if the routers receive packets with DSCP = 101110 that means expedited forwarding (EF), the routers are requested to forward the packet for low latency and low-loss service. Assured Forwarding (AF) that defines three levels of drop precedence is also defined and is used to guarantee the minimum bandwidth. When this field is used as Differentiated Services, the default value is 000000, meaning simply that the best possible service is being provided.
3.1.2. Real-time ARQ (Automatic Repeat request)
The Real-time ARQ is a mechanism that automatically resends lost packets and reorders received packets. Thanks to Real-time ARQ, the PCS-1 can recover almost completely from a packet loss rate of 10%, automatically maintaining the minimum latency according to the network environment.
Figure 3.1 describes how Real-time ARQ works. The packet loss of an RTP packet of video/audio bit stream is detected on the receiver side. A resend request is then sent to the transmission side using an RTCP (Real-time Transport Control Protocol) packet. On the transmission side, the transmitted packet is held, preparing for resending according to the resend request. By using an RTCP packet, the Round-Trip Time (RTT) or network latency can be measured. If the RTT is large, it would be a waste of network traffic to send the resend request knowing that the resent packet would not arrive in time for decoding. Sonys Real-time ARQ is capable of determining whether or not the resending packet would arrive in time, and adaptively selects the optimum algorithm according to the RTT and packet loss rate. Figure 3.1 Real-time ARQ resending diagram

B. Adaptive algorithm switching In addition to the buffer size, the resending algorithm itself is adaptively switched according to the RTT and PLR. For example, if the network latency (RTT) is very large, redundant audio transmission is used instead of packet resending to maintain conversation quality. C. MCU and presentation data Real-time ARQ works in combination with the internal MCU function. When the MCU function is engaged, each link between the terminals and the PCS-1 with MCU function uses ARQ to recover from packet losses. Additionally, when the PCS-DSB1 (Data Solution Box) is used, presentation data can also be recovered from packet losses.
3.1.3. Adaptive Rate Control

RTP RTP

Lost Packet 2!
Request Resending Packet 2

Resending Packet 2

Adaptive Rate Control is a mechanism used to slow down the video bit rate if network congestion occurs. Unlike similar conventional methods, the PCS-1 employs a TCP-friendly rate control which adjusts to other TCP traffic (e.g. FTP) having its own rate control functions. TCP-Friendly Rate Control (TFRC) is designed for unicast flows operating in an Internet environment and competing with TCP traffic. The TCP throughput equation in IETF RFC3448 is a function of packet loss rate, and RTT should be suitable for use in TFRC. Figure 3.2 is an example of the calculated target video bit rate. Figure 3.2 Adaptive Rate Control (for example, max_video_rate is 960Kbps)

Tpi: Packet Interval

A. Minimum latency with optimum packets buffering In general, resending packets requires a receiver buffer for reordering of packets, and hence increases the system latency. Sonys PCS-1 has a variable-length reordering buffer for rearranging a packet in order of the sequence number of RTP headers. The size of the reordering buffer is optimized according to the measured network RTT and PLR (Packet Loss Rate). In an environment without packet loss, the reordering buffer is minimal and hence the communication latency is not affected. In the worst case, Adaptive Rate Control decreases the video bit rate to 1/4 of the initial bit rate, or the minimum video rate of 64Kbps.
3.2. Internal MCU Function Outline
By using the internal MCU function, up to five videoconferencing terminals can be connected to the PCS-1 in both H.320 and H.323 modes. Small-scale multi-point conferences are supported without external MCU equipment. In addition, both H.320 (ISDN) and H.323 (IP) calls can be connected on a single multi-point conference call using the H.320/323 bridging function. The MCU function of the PCS-1 offers all basic functions as MCU, such as FECC (Far End Camera Control), broadcast mode, and continuous presence/voice activation function. Whats more, if only PCS-1s are connected, it is possible to support the digital whiteboard function and PC data-sharing function in a multi-point conference environment. The maximum 10-site meeting is attained through the cascade connection of two PCS-1s with H.323 MCU function installed.

Main features

Supported protocols Number of connected terminals
H.323(LAN), H.320(ISDN), H.323/H.320 Mixed Up to 6 terminals in H.320, H.323, H.323/H.320 Mixed mode Up to 10 terminals by cascading two PCS-1s with MCU function. The connection between two PCS-1s with MCU function must be based on LAN (H.323). H.263, H.261 CIF/QCIF G.711, G.722, G.728 H.323 Number of Sites 5 H.320 Number of Sites 5 Max Bandwidth (Kbps)/each 128 Max Frame Rate 7.5 Max Bandwidth (Kbps)/each 384 Max Frame Rate 15
Video Coding Audio Coding Maximum bit rate and frame rate
H.323/H.320 Mixed In mixed mode, the video rates (not total rate) are matched between the ISDN and LAN interface. For example, if a PCS-1 set at G.722 audio is connected via two B channels of an ISDN line to a PCS-1 set at 1024Kbps LAN bandwidth and G.728 audio, the video rate becomes approximately 96Kbps, which is the video rate of the ISDN connection. The total bandwidth for PCS-1s that are connected via LAN becomes approximately 160Kbps (video: 96Kbps, audio: 64Kbps).
Display Mode Continuous presence (Split), voice activation, and broadcast mode
Continuous Presence Layout Four-way and six-way split-display modes are supported depending upon the number of sites connected. 4Site Up to 3 terminals:

FAR1 FAR2

6 Site 4 to 5 terminals. There are two modes, voice-activated and fixed-mode, for selecting the site in the large window. 1 voice-activated mode When FAR5 is talking:

FAR1 FAR2 FAR3

When FAR3 is talking:

FAR1 Near FAR2

FAR4 FAR5 Near

FAR4 FAR3 FAR5

2 fixed mode The MCU terminal selects the site in the large window. When FAR1 is selected:

Near FAR2 FAR3

When FAR3 is selected:

FAR4 FAR1

H.281 FECC (Far End Camera Control) is available in H.320, H.323, and H.323/320 mixed modes. In H.320 mode, H.224-LSD 6.4Kbps is used. In H.323 mode, H.224 logical channel is used. The camera at the site currently displayed in full-screen mode can be controlled at the terminal with MCU or at other terminals. In the continuous-presence mode, FECC is not supported. Whiteboard data is transmitted using H.224-LSD in H.320 mode or using H.224 logical channel in H.323 mode. Sonys original data format and protocol are used. Moreover, the MCU terminal controls other terminals using original token management protocol in order to select one terminal for transmitting whiteboard data in conferencing.

Whiteboard

Data sharing function
The PCS-1 MCU enables data sharing of XGA data. XGA data from one site, which can be the terminal with MCU function, is automatically distributed to all the other terminals. The PCS-1 MCU function controls other PCS-1s so that XGA data from two or more terminals is not transmitted simultaneously and transmission of XGA data is prevented while the PCS-1 is receiving XGA data. Moreover, when XGA data is transmitted, the video signal is controlled so that the video of the terminal to which XGA data is sent, is selected and transmitted to all other terminals in H.323 mode. On the other hand, the split mode can be maintained even when XGA data is transmitted in H.320 mode. Availability of a dual stream of video and XGA data depends on the modes. In the case of H.323 mode, dual streaming of video and XGA data is possible if all the terminals are PCS-1s with Version 2.0 firmware installed or if the terminals are a combination of PCS-1s with Version 2.0 firmware or with Version 1.0/1.1 firmware and RGB output ON. Otherwise continuous transmission of 4CIF still picture is used. In H.320 mode, dual streaming is possible only when all the terminals are PCS-1 with Version 2.0 firmware. In H.323/H320 mixed MCU mode, only the continuous transmission of 4CIF still picture is supported. XGA data transmission will become available when the transmission format of dual streaming fully supports the H.239 ITU-T standard in H.323 mode.

Cascading

Connection of PCS-1s with MCU function is supported in H.323 mode; up to 10 terminals can be connected. The functions of FECC/Whiteboard/RGB Data sharing are supported. When two PCS-1s with MCU function have a cascade connection and another PCS-1 with MCU function attempts to connect, it is disconnected automatically. Continuous-presence mode is not supported. When a cascading connection is established, the split-screen mode automatically changes to full-screen mode.
3.3. Advanced Video and Audio Coding Technology 3.3.1 H.264 (MPEG-4 AVC)
Table: Audio CODEC Algorithms on PCS-1

Audio Bandwidth

3.4kHz
Also known as MPEG-4 Advanced Video Coding (AVC), H.264 is an emerging video compression standard. This is the product of the Joint Video Team of ITU-T and MPEG, officially ratified as H.264 on May 2003. Although the H.264 algorithm requires huge computation power, approximately 40-50% lower bit rate is needed to achieve the same picture quality as any of the previous encoding standards, such as MPEG-4 and H.263. H.264 produces significantly better picture quality at a low bit rate. A very powerful digital signal processor (TI C64x) used in the Sony PCS-1 provides 30 fps H.264 encoder and decoder capability. Software Version 2.0 or later supports H.264 capability, which is used as a default codec except in the Motion Priority mode, or when the other side does not support H.264. Table: History of Video Coding Standards

ITU-T ISO/IEC (MPEG) H.261

Sampling Frequency (FS)

Algorithm
G.711 G.723.1 G.728 G.729

Data Rate

56Kbps, 64Kbps 5.3Kbps, 6.3Kbps 16Kbps 8Kbps 48, 56, 64Kbps 24, 32Kbps 64, 96Kbps

G.722 G.722.1

MPEG-4 AAC

3.3.3. Interlace Video

Software Version 2.0 or later supports Interlace SIF video with 60 fields/sec in NTSC and 50 fields/sec in PAL. The SIF (Source Input Format) is 352 x 240 (NTSC) and 352 x 288 (PAL), and interlaced SIF results in twice as much vertical resolution with 352 x 480 (NTSC) and 352 x 577 (PAL). As with the 60 fields/sec frame rate, the motion is much smoother than in the 30 fps conventional CIF. This mode uses ITU-T recommendation H.263 Annex W and is provided only in point-to-point connections. Please note that in this mode, the amount of data transmitted is twice as much as in the 30 fps CIF, and hence a higher bit rate is required to provide sufficient picture quality.

3.3.4 MPEG-4 Video

H.262 H.263 H.263(v2) MPEG-1 MPEG-2

MPEG-4 MPEG-4 (AVC)

3.3.2. MPEG-4 AAC Wideband Audio
In order for all of the participants in a video conference to feel as if they are in the same room, high-quality audio is critical. Conventional videoconferencing equipment covers only the speech bandwidth. Most of the voice CODEC algorithms support 3.4 kHz telephone-line-quality bandwidth (FS = 8 kHz), and even using wideband G.722, the bandwidth only extends to 7 kHz (FS = 16 kHz). The Sony PCS-1 offers MPEG-4 Advanced Audio Coding (AAC) among its various audio CODEC choices. The AAC is designed to compress high-quality audio, such as music, with extremely high coding efficiency. Sonys implementation in the PCS-1 uses the bandwidth of 14 kHz (FS = 32 kHz), enabling the conference to share the atmosphere of the remote site. The PCS-1 turns on the MPEG-4 AAC audio when using an IP-based connection. Sonys videoconferencing endpoints use well-proven high-quality acoustic echo and noise cancellers, which quickly adapt to the environment of each conference room. For the PCS-1, Sony developed a wideband echo canceller algorithm to accommodate 14 kHz audio bandwidth.
MPEG-4 (ISO14496) is an ISO/IEC standard developed by MPEG (Moving Picture Experts Group), and it became an international standard at the beginning of 1999. MPEG-4 addresses the need for distributing rich interactive media over a variety of networks. MPEG-4 is widely used for high-quality video over IP networks, including streaming media over the Internet using PC, PDA, and 3G mobile phones. While MPEG-4 has many profiles and levels to accommodate various applications, the PCS-1 has adopted the most widely used profile, Visual Simple Profile. The MPEG-4 Visual Simple Profile (SP) is based on the H.263 compression algorithm. It also shares many of the H.263+ tools defined in the Annexes of H.263, such as Deblocking Filter, Advanced Intra Prediction, and Unrestricted Motion Vectors. With some additional tools, MPEG-4 SP gives slightly better picture quality than H.263+.

3.4. Whiteboard Function Outline
The PCS-1 is equipped with direct I/F for the Mimio XiTM digital whiteboard recorder from Virtual Ink Corporation. Using Mimio Xi, notes and drawings on a conventional whiteboard can be electronically converted and then transferred in real time to remote sites for onscreen display. This function is supported in various modes, point-to-point and multi-point configuration, including cascading connection in H.323 and H.320 modes. It is possible to share notes and drawings on a whiteboard on the screens of all the connected terminals as well as to save the data of the drawings to a Memory Stick.

Functions

companies and organizations, as well as the Internet, which malicious hackers can easily attack, a function to encrypt the data transferred through the IP network is essential. It is also important to prevent unauthorized users from logging in to the PCS-1; otherwise malicious users could eavesdrop on a conference as a web client, or secretly change the setting of the PCS-1 by logging in using Telnet or as a web client. A password protection mechanism is therefore provided to prevent access by unauthorized users.

Encrypting data

A. Real-time drawing You can draw a picture using a 4-color pen, large eraser, and small eraser. A picture of the drawing is displayed on all the terminals in the conference in real time. B. Transmitting data All drawing data is transmitted using H.224-LSD in H.320 mode or H.224 logical channel in H.323 mode. The maximum data transmission rate is 6.4Kbps in H.320 mode and 64Kbps in H.323 mode. Data sharing of the drawings through a network with limited capacity is made possible by processing and compressing the data of the drawing. C. Display on RGB monitor or TV in dual-screen mode One monitor is used for pictures of the conference and the other monitor, an RGB monitor or TV, is used for whiteboard. D. Saving images to Memory Stick as JPEG files You can save a picture of a drawing to Memory Stick as a JPEG format file at all terminals in the conference. The size of a JPEG format file is 1024 x 768 pixels. E. Whiteboard The only whiteboard the PCS-1 supports is the Mimio Xi from Virtual Ink Corporation.

3.5. Security

It is possible to encrypt data only with a LAN connection, and in Point-to-Point, MCU, and cascade mode, only if the connection is H.323-based and all the end points connected are PCS-1s. In H.320 and mixed-MCU mode, the encryption function is not provided because ISDN connection is a closed connection and the security level is much higher than with an IP connection. Video, audio, and DSB data are encrypted. Data for far-end camera control and whiteboard images are not encrypted. There are two factors that must be considered when implementing the encryption function: the encryption algorithm itself and how the encryption key is delivered. In regard to the encryption algorithm, we adopt the AES (Rijndael) algorithm, which is the abbreviation for Advanced Encryption Standard, selected by the U.S. National Security Agency as its next-generation algorithm. The encrypted part of the IP diagram is limited to the payload part of RTP (real-time protocol) packets based on UDP. AES uses a 128-bit symmetric key, and the sender of a message and the receiver must hold the same encryption key. Known by both the sender and receiver, the password is used to generate the common encryption key. Since a proprietary Sony algorithm is used to generate the encryption key from the password, it is not possible to communicate with videoconferencing terminals from other vendors, like Tandberg, even if the encryption mode is set to ON. To initiate encrypted videoconferencing, the password with 13 to 20 alphabetical characters, numerals, or symbols must be registered at both ends. Encrypted videoconferencing can be established only if the passwords at both ends match.

Needless to say, it is of the utmost importance that corporate users have a conference system secure enough to hold confidential meetings and exchange confidential data. Because videoconferencing now uses both an Intranet, which is installed only inside

Password protection

The PCS-1 supports three levels of the password protection system. It is assumed that the system administrator sets up the passwords on the setup menu if necessary. Administrator Password For cases in which the administrator password is set by the administrator, users must enter the password in order to change any settings in the setup menu or phonebook. Users must also enter a user ID and password to log in by Telnet. Super User Password For cases in which the Super User Password is set by the administrator, users must enter the password in order to make any changes to the phonebook. Remote Access Password For cases in which the Remote Access Password is set by the administrator, users must enter the user ID and the password to access the PCS-1 via a web browser in order to control the PCS-1. It is also possible to access the PCS-1 via a web browser as administrator or super user.

3.6. PPPoE

The procedure for obtaining the IP address by PPPoE consists of two steps as shown in the chart below. 1. User Authentication 2. Global IP Address Allocation Figure 3.3 The procedure for obtaining the IP address by PPPoE
H.323 protocol requires that the global IP address be embedded in the data area of the IP packet. Therefore, when an NAT router is used to connect the PCS-1 to the Internet, users must enter the global IP address assigned to the NAT router on the PCS-1 setup menu in order to have it in the data area. However, it is not easy for non-technical end users to understand the meaning of entering a global IP address. PPPoE eliminates this troublesome procedure and enables the PCS-1 to be connected directly to the Internet. Standardized at IETF and defined in RFC1661, PPP is the most proven architecture, having worked well for dial-up for more than a decade. By requiring a password/ID handshaking procedure before network configuration is granted, this approach inherently supports the authentication process required to track usage and to bill for services accordingly. The line can be ADSL, FTTH, or CATV, if the modem interface is Ethernet.
The PCS-1 is connected to the Bridge via Ethernet. The broadband access server of the ISP resides at the facility of the telecommunications company. First the PCS-1 will request user authentication from the BAS with the User ID and Password. If authenticated, the BAS will provide the Global IP Address to the PCS-1. Then the PCS-1 can communicate with remote terminals through the broadband network.

3.7. Dual Video Stream

In both H.323 and H.320 mode, RGB data is transmitted using additional video channels. In the case of H.320 mode, the protocol is fully compatible with the H.239 ITU-T (Role Management and Additional Media Channels for H.300-series Terminals) standard, and terminals from other vendors should be able to connect to the PCS-1 if those terminals support the H.239 standard. In the case of H.323 mode, the dual-stream protocol is Sonys original format and the PCS-1 cannot be connected to videoconferencing terminals with dual-streaming function from other vendors. Standardization activities to enable interoperability among videoconferencing terminals from various vendors have started in Study Group 16 of the ITU-T. The first baseline document on the standard was jointly proposed by Polycom and Tandberg at the Rapporteurs Meeting in February, 2003. At the ITU-T meeting held in May, 2003, H.239 has been approved by the Alternate Approval Process (AAP).