【 Weak current College 】 enterprise-level video conference system five top technical details

According to the market advisory company WinterGreenResearch forecast, the unified communications market development cycle is about to step into the healthy growth and rapid application of the stage. In 2008, the market may achieve 15% growth in 2009 will grow by 30%. And video in the enterprise-class unified communications deployments will be uncompromising black horse.
Traditional enterprise video technologies include: MCU, H. 323, frame relay, and IP network-based video application, would bring more rich functionality to the user. But to successfully use these features, the user needs to some new hot technology to give more attention.
A LPR: get stable video stream
Unified communications enterprise voice, video and data synchronization hosting over IP networks to transfer the video data packets, which inevitably encounter network packet question. Packet loss will result in video image mosaic; image local deformation, frequent refresh or flashing screen; video and audio are not synchronized; frame rate drops and the still image. In unified communications, video, voice and data flow is synchronous transmission, packet loss will result in overall audio distortion, continuous or intermittent noise, as well as the quality of the content of the presentation, such as fuzzy distortion of slide or page slower, etc. These issues will significantly impact the consumer experience of application. If the network packet loss rate is too large or too frequently, will cause the excessive delay for video communication, or even result in loss of communication.
Packet loss is congestion by internal or external network priority flow caused by the conflict, etc. To avoid loss, it is first necessary to determine the host network packet loss rate, packet loss distribution over time, as well as a video call in various terminals and equipment performance.
LPR (packet loss recovery) is the current resolution of video transmission packet loss of one of the most effective method, the technology is based on Polycom company developed a new algorithm, with the aim of protecting IP video call from the effects of network packet. In fact, LPR is a use of forward error correction (FEC) method to override the implementation of lost packets. By the sending system to issue a data stream to add redundant data so that the receiving system can detect and correct the error without having to request the sending system to transfer the missing information. This is not required to wait for the network will have the ability to correct, make the FEC is ideal for real-time communications, such as television broadcasting, IP telephony and IP video conferencing.
LPR works through video Terminal control all ongoing calls inbound packet information. Once detected, packet loss, the terminal will take three means to guarantee call quality: lost packet recovery (LPR), the dynamic bandwidth allocation (DBA), and does not support LPR, using the traditional video error yinxiao (PVEC) technology.
Unlike most mistakes avoidance algorithm only yinxiao or intervene in receiving packet loss information system, LPR will intervene to video call in all levels of the system, part by temporarily assigned to a call bandwidth data channel, which is used to send FEC data to the receiving system to play a role. In the network packet loss occurs, a loop through the above process, LPR will increase or decrease the size of the FEC data channel until you find must be assigned to the FEC data channel minimum bandwidth, allowing the receiving system to be able to recover all lost packets.
When the FEC data channel is larger than the standard value, the system will detect whether you can reduce over FEC data channel size for audio, video and content data provide more bandwidth available on the phone. Since LPR only detect packet loss will only be occupied bandwidth, this feature makes the LPR is great for random or unexpected packet environment.
Against packet loss rate relatively fixed network environment, the dynamic bandwidth allocation (DBA) function in conjunction with LPR. DBA is also a kind of algorithm, you can video call process automatically and dynamically adjust the video bitrate, to eliminate or avoid packet loss. For example, in a video call 384kbps detected a stable at 10 percent packet loss rate, the DBA will decrease by about 10% of the video bit rate to minimize by 320kbps 288kbps left and right, and resampling signals, to see if there are packet loss. If necessary, the DBA can further reduce the video bit rate, until a few seconds until it no longer appears lost packets.
At lower bit rates, if measurement of packet loss for the DBA temporary phenomenon, the DBA will gradually increase the video bit-rate. Conversely, if the DBA continues to detect packet loss, it will no longer resize video bit rate, but will continue the call. Therefore DBA applies to Internet overuse or throughput problems caused by packet loss environment.
The parties involved in communication systems do not support LPR, you can use video error yinxiao (PVEC) feature. PVEC is an IP video quality of service (QoS) algorithm, it can by packet loss effects caused by the compensation. It is through the use of neighboring macroblock, front frame and the rear frame to estimate the current contents of the video frame. And LPR recover lost packets and DBA avoid packet technology, the role of the obscure PVEC packet loss.
On this basis, the LPR that users can BER higher IP networks (DSL, cable, satellite, high conflict and LAN/WAN, etc) for high quality video calls without having to endure the consequences of lost packets. Through the ongoing call rate for temporary adjustment, LPR can protect a video call from short-time network problems. Once the network problem solving, LPR will initiate the call rate or current bandwidth availability, automatic bit rate back to the highest level. This makes network bandwidth can be fully utilized to achieve the recovery of lost packets and transmission of real-time reconstruction so that the audio and video data stream patency, exclude waiting, intermittent, noise or information clutter, more capable of reducing the dynamic jitter buffer space and the associated delay.
But use LPR generates FEC channel bandwidth, the use of the video call itself reduce the available bandwidth. In the low connection speeds, can cause temporary reduced frame rate or resolution.
Restore the scene: a face-to-face experience
Users for video image is clear, the real requirement is that there is no upper limit, which directly led to Cisco, Nortel Networks really really far and the birth of the HP Halo to these products as representative, the application will take advantage of enterprise video-high definition technology, the experience of implementing reduction field.
Unlike traditional video conference system, the most obvious of these products is characterized by its ultra-high-definition resolution. According to reports, the network's system uses three high-definition plasma display, each screen resolution can achieve 1080 × 1080p, than the existing international standards in HD resolution (1280 × 720p) twice, is an ordinary TV resolution 10 times. Provides 6 people at the "virtual meeting" of the network's 3000, each plasma screen required bandwidth in 2 ~ 3 screen between 4Mbps, total needs around 10Mbps bandwidth, ordinary ADSL is not possible to host, so the need for specialized dedicated line access or fiber access. Ultra high performance capabilities of the image with high-fidelity audio, as well as ergonomic environment design, the Cisco network's performance in meeting system to real exchange in every detail, such as "clear the whites, the hairs on the skin, as well as the communication between each other slightly shy look", etc. It is understood that the net prices actually is 7.9 ~ 29.9 million in AMD, Pepsi, GE and other large enterprises.
HP's Halo Studio systememphasizes that can be used for corporate remote simulation face-to-face business meeting. Connect through Halo Halo Studio, each can support the Conference table in front of six persons, the second row of three to six persons, up to 12 people in the meeting size. Each Studio have three plasma display, participants can see and I the same size of the image. In addition, attendees can also use an installation in the plasma display above the 50-inch screen, in collaboration with other Halo Studio staff share their notebook computer files and data. Studio also includes a high-definition picture and video camera, can be used for filming the items on the table and displayed in collaboration on a monitor, real render color, shadow and subtlety. At the same time equipped with phone let attendees can work outdoors and Halo. Studio equipped with broadcast-quality audio and lighting facilities, the participants can use the screen and easy user interface, start by clicking on the mouse. A complex software control system will ensure that Halo Studio easily and seamlessly work together.
HP Halo adopts high-bandwidth, separate connection of specialized video switching network provides full-motion video HVEN experience, which makes global Halo Studio audio or video delay will not be people perception. In order to ensure a 24 × 7, HP provides include: network operation and management, remote diagnostics and troubleshooting, security protection, equipment maintenance and subsequent maintenance and repair services. Users do not need to manage Halo Studio operation and maintenance.
Currently, HP has 18 countries worldwide and has over 60 such Studio.
According to reports, the HP Halo collaboration Studio package for the price of the room is 39.9 million dollars, plus monthly 2.4 million ~ 2.5 million in service fees. At present, the user already includes Halo dream factory, Novartis, AIG financial products, BHP Billiton (BHP Billiton), Canon, and other well-known companies.r>Nortel's ultimate far really (Telepresence) system is fully embodied communication "rendering", life-size screen, HD seamless video effects and StereoSurround sound effects, collaborative multimedia content to show, video multipoint control technology (MCU) recording, archiving, streaming media and high-definition support services. More optimization is that this kind of experience you can demand from two small meetings, to be able to accommodate up to 28 people large meeting room, users can realize high-definition video communication and at the same time seamlessly show film, data tables and other collaborative format the content of the document, is equivalent to a complete virtual people in the Conference room is able to complete all activities. The entire process is based entirely on offsite meeting environment of far from true.
Extreme far really system characterized by modular features; Studio-grade lighting; professional acoustic treatment; no remote control and human-machine interaction control; hidden-camera; microphone and PA system. Each element is designed to integrate fully reflects the technology of seamless and transparent as well as the organic integration of the physical environment, forming a unified environment for audio and video conferences. In addition you cannot shake hands, and face-to-face meetings have no difference.
Nortel is really a standard turnkey, Nortel offers a comprehensive set of services. Including the scene investigation, network assessment, project management, open services, 7 × 24-hour support, and is designed for high-definition system MNOC multimedia services, 24 x 7 meeting booking, proactive remote monitoring, Conference building, confirmation and reporting of monthly remote services.
QoS: high-quality transmission security
In the network application QoS is not new technology, but in video hosting online streaming media QoS is a new hot technology.
Business-to-video technology innovation is streaming media technology into the mainstream of the application. Streaming media playback with strict requirements, the requirements of real-time at specific intervals to decode a specific data cell. Currently streaming media business in a number of issues, such as media files playback pause, mosaic phenomenon, there are a large number of users access a top emergency content server processing difficulties, and so on, these issues are related to streaming media QoS guarantee.
Enterprise video because of the mostly applied to business-critical, and the transmission of voice, data synchronization, network quality with higher requirements. Streaming media QoS needs to address two issues, bandwidth and delay jitter.
It is well known,Video and voice and unified communications is the most consumed bandwidth in the network application. Bandwidth limit on the one hand, affect the quality of video playback; on the other hand, because the streaming media applications consuming bandwidth, and network with other business in the contend bandwidth on the business impact of normal operation.
In addition, IP network for video data grouping store and forward mechanism determines the latency and jitter is inevitable, therefore convective media transport, the end-to-end delay should be controlled to a certain range. Streaming media QoS with advanced video coding schemes, in improving the efficiency of the video data compression, as far as possible eliminate redundant information in the video, making source code output for as little as possible the amount of data, thereby adapting the minimum transmission bandwidth of the network. At the same time, you can provide flexible video quality rating to best adapt to the dynamic nature of the network, as far as possible, providing users with better video quality.
Scalable coding technology increases the encoded output stream, adapted to network bandwidth, the flexibility of dynamic change, multimedia data compression into multiple streams. One can decode, called basic Bitstream, other stream called enhanced layer. They are not individually decoded, but only with the basic layer and its previous reinforced layer combined with decoding, used to improve viewing.
State rendering: implement transparent communication
Reference to presence (Presence), the first thought is QQ, MSN, instant messaging (IM) application. The video is already realized the communication between the face-to-face communication, you also need to get familiar with its state information?
The answer is Yes. Especially in the enterprise business process integration of video communication, Presence technology and video combination will become a new focus on technology. In fact, in the enterprise, individual business processes based on the Unified Communications launch and execution of the process, you can make good use of the State service for dialogue between the transparent communication.
Presence to communicate user status, and the users through a set of devices for communication, such as: online, busy, away, offline, etc. These status information reflects the user to communicate with other users.
A simple Presence as follows: one user (Watcher) subscriptions (SUBSCRIBE) in the interest of another user (Presentity) Presence status, receive subscription request Presentity. Later, when the status of the Presentity changes, he will publish (PUBLISH) your new status, this new status will notify (NOTIFY) to the Watcher.
From a systems perspective, video headend equipment and IM system users have many similarities. For example, the system should always know the front-end device is logged into the system; whether it be user access, and which users access, and so on.
Five protocol compatibility: in the mix in the consolidated
In addition to the video itself a hotspot of technology in the enterprise, in addition to the application and deploy an IP video system, and you want to achieve and speech, data communications platform of"unification", as well as individual enterprise management decision mutual integration of business processes and embedded, faced with cross-network interoperability, cross-functional interoperability and cross-device communication problems.
In theory, the video can provide all aspects of corporate operations provide diverse wealth of services, from the most common meetings, monitoring to broadcast, communications, mobile, and other end-to-end interactive features. To video to promote, in the framework of the unified communications, enterprises can build their own open, performance improvement and powerful information exchange system. But this also brings about another issue, are designed for different applications, may have different protocols and standards, these standards and protocols in a single IP-based unified communications hosting Internet compatibility. Together with the enterprise in the deployment of their video communications systems, hardware and software system has different options, you can build a supporting rich Protocol and is compatible with various standard to achieve in a single network environment to provide more application functionality integrated platform, will become a corporate video deployments are most often in the face of one of the technical difficulties.