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Video Servers Bridge the Gap Betwee Analog and Digital
a&s International 2007/7/12

Network IP solutions are touted as the answer for security problems, but analog cameras dominate most existing camera configurations. Video servers span the distance between analog and digital systems, upgrading existing systems and holding tantalizing potential for newer uses.

Network IP solutions are touted as the answer for security problems, but analog cameras dominate most existing camera configurations. Video servers span the distance between analog and digital systems, upgrading existing systems and holding tantalizing potential for newer uses.

One benefit of digital systems is faster response time, with video servers br idging the gap between legacy analog systems and digital IP systems. The universal function of a video server is to transform analog signals into digital signalsimportant in places with existing analog frameworks. This has fueled demand for video servers, said Hong Kong-based TeleEye.

"Basically, we foresee that, for the analog traditional camera, there will be a lot of varieties, a lot of choices in the market," said Wallace Ma, Chief Marketing Officer for TeleEye. "Even at this moment, there is a big demand for the video servers. For the traditional camera with different specifications, there is room for different operations, such as an infrared camera. I think that choice of camera is one issue." 

Specialty analog cameras for mines or military applications need video servers to transfer images to digital signals, said Frank Yang, Sales Director of ACTi. Video servers allow existing analog hardware to continue running, without requiring an all-new IP solution, while upgrading hardware to digital connectivity. This helps reduce costs, networking old and new cameras.

Price sensitivity is another factor as countries with tighter budgets choose products with fewer features at reduced prices. ACTi's single-channel, quad video server, which splits images into four quarters, sells well in less-developed Third World countries that cannot afford more expensive, higher resolution images, Yang said. Conversely, its four-channel video server, which streams out four D1-quality, MPEG-4 transmissions, goes to higher-end markets that are able to support sending higher resolution images. This is better than competing products, which take four inputs and compress them into lower-resolution CIF format. When image quality is a priority, full-resolution transmission is better than compression by a DVR.

Practical concerns make video servers a good option. "IP speed domes are very expensive," Yang said. "An analog dome plus a video server is more cost-effective."

Achieving Performance in Integration and Resolution

As signals are transmitted by digital format, video servers can also reduce bandwidth, depending on the compression. TeleEye offers a unique format that, it says, improves performance by reducing network demand and increasing transmission speed.

"We have designed a revolutionary video compression, SMAC-Mmultistream video technology," Ma said. "With SMAC-M, there is no compromise on video performance. SMAC-M compression outperforms MPEG-4 with a data size of 40 percent less. The transmission rate is 50 percent faster that MPEG-4 over an ADSL, broadband Internet connection. Inefficient compression results in unsatisfactory performance."

Some companies offer more than one transmission format, allowing the user to choose the format best suited to their needs. A-MTK of Taiwan offers multiprofile video servers capable of supporting MPEG-4 and MJPEG simultaneously. "One video server can fit in different network environments," said Pauline Yen, Sales and Marketing Director. "Users can flexibly select the best video resolution and encoders."

Zavio also supports multiple formats. "Motion JPEG and MPEG-4 dual streaming provides the best image quality and smoothest streaming video," said Terence Wang, Product Manager. Its solution features built-in Power over Ethernet, or PoEeasy installation that does not require a technician is thus assuredand continued operation even in the event of a power outage.

ACTi video servers receive analog signals and transmit them as MPEG-4, MJPEG or H.264, Yang said. This means users can choose any compression format compatible with their existing systems. Digital signals transmitted in specific formats, such as MPEG-4, can transfer to other formats.

Yang also pointed out some key features when comparing video servers. ACTi solutions produce full-resolution image streams because camera images are processed on dedicated application-specific integrated circuits (ASICs), rather than having the same chip processing multiple camera feeds. This allows for sharper images than with single chips compressing feeds into lower resolution formats.

With multichannel video servers, each channel has audio capabilitiesrather than multiple video streamsand a single audio channel, which transmits not only sights but also sounds. Finally, more than one digital in/ output on the video server allows for sensors and alarms to transmit warnings in a timely fashion. These features make video server integration a vital part of effective security.

Video Servers in Surveillance

Remote monitoring allows real-time feeds and identification of threats. As a result, several companies have Internet capabilities on their video servers. A-Linking's video server monitors equipment and facilities at offices or secures homes remotely, as long as there is a networked computer, said Joyce Wang, Sales Manager for A-Linking. "It has been used in homes, enterprises, offices, organizations, banks and communities." Making video accessible online is also a feature of A-MTK video servers, which are used for small and medium-sized businesses by supervisors to remotely monitor offices, Yen said. "Moreover, with A-MTK 3GPP mobile surveillance, guard companies can check live views via mobile phones and reduce false alarms." 3GPP refers to transmitting MPEG-4 quality images for viewing on mobile devices.

"At the moment, most TeleEye products are used for remote monitoring," Ma said. He said the majority of solutions are used by multinational corporations with several offices in different countries. Other vendors find current compression methods satisfactory and compatible with third-party systems. Korean iCanTek uses MPEG-4 compression to send video over networks at D1 resolution, said Oscar Yoon, General Manager of Marketing and Sales. The video servers function as embedded Web servers, so video can be streamed directly from the video serverthey do not require a central computer to process images.

"Our product provides MJPEG, while at the same time, streaming for mobile networks," said Yoon. "Our product provides PDA phone and Java viewers for mobile phones."

Asian Makers Have an Edge

While it would seems that demand for video servers might slow with growth of megapixel cameras and DVRs, video server makers say otherwise. All markets are using video servers due to gradual increases in remote monitoring and central management, Wang said.

Asian manufacturers dominate the market, Yang said. "Asians are stronger in manufacturing; North Americans and Europeans do not manufacture that much anymore. They are looking at ways to integrate products and features, like including a stabilizer or people counter. After adding more functions, however, it just puts the video server at the top of the pyramidthe rest is basic functions, such as compression, audio inputs, DI/O, compression. Profit margins for Europeans and Americans are too low."

These advantages have enabled Asian makers to corner the market. Higher-end features may not be included, but for mainstream and even consumer markets, the Asian strategy seems to be working. Digital surveillance will still require video servers for some time to come.

The Video Server of Tomorrow

With the migration to IP technology, video servers will need to adapt beyond being a bridge from old to new technology. Some makers say the line between video servers and digital video recorders is blurring. Whether this spells doom for video recorders is anyone's guess.

Yoon believes that video servers need more functions to stay up-to-date. Additional functionality, such as remote pan-tilt-zoom control of cameras through video servers, rather than DVRs, must be added for video servers to remain relevant. The company offers a solution that is applied in banking, he said. As ATMs require at least two cameras, iCanTek's video server has local storage to record images while transmitting them through the network, making for a complete package of video offerings.

Keeping basic functions running at their best is what ACTi feels video servers should do. ¨Hybrid or convergence features require analytics for image quality, such as a stabilizer, or for user-friendliness, such as a people counter,〃 Yang said. ¨Where the analytics should be applied, such as on the video server or IP camera or on the backend, has not been decided. I do not, however, think that it is wise to put analytics on video servers.〃 The high cost of software licenses also makes embedded video servers cost-prohibitive. 

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