Avocent Emerge WMS1000
Dec 1, 2005 12:00 PM, By Jeff Sauer
Wireless device transmits MPEG-2 component video.
In last month's Sound & Video Contractor I reviewed ViewSonic's Media Gateway WMG120 and Media Adapter WMA100. That combination sends video and audio over IP, either via a wired LAN network or wirelessly through a built-in 802.11b/g antenna. On the surface, Avocent's new Emerge WMS1000 wireless media transmitter and receiver, reviewed here, might sound like much the same type of product, but that's not really the case.
Avocent's new Emerge Wireless Media Streamer is from a family of Avocent products that includes the LongView Wireless Extender, introduced in 2004 as a wireless replacement for a long RGB cable run. For the most part, Emerge does the same thing, except it's optimized for motion video rather than computer desktop images. LongView and the Emerge use different image compression and have different I/O ports, but how are they different from ViewSonic's streaming video products?
Both Emerge and the ViewSonic solutions use MPEG-2 video compression to move video data between devices (the LongView uses propietary compression optimized for computer desktop text and graphics). However, the ViewSonic Media Gateway and Adapter are designed to integrate with and stream/play existing files. This works if you have files residing on a computer hard drive or other attached storage, but the device has no ability to encode video or transmit “live” feeds in realtime. ViewSonic's solution is also built to be integrated into a standard LAN and IP infrastructure, although the Media Gateway is a router and DHCP server itself.
Avocent's Emerge, on the other hand, has no storage component or intelligent interaction with any stored files. Instead, it is designed to replace long, impractical, or unsightly video cable runs. Therefore, it is a closed point-to-point “network” and does not use existing Ethernet LANs. (Avocent does offer an Emerge product, the MS1000MP, for multi-point one-to-many video distribution, but it is a wired LAN solution rather than wireless.)
Physically, the Emerge transmitter ($645) and receiver ($545) are both small boxes, about the size of a typical four-port wireless router/hub. The difference is that rather than Ethernet ports on the back, they each have a set of video ports — an RCA composite jack, a five-pin S-Video port, and 3xRCA component video jacks — and a stereo mini-jack for audio for connecting to the source on one end and a video monitor on the receiving end. There is also a 15-pin RGB port and an RS-232 port for control, and all of those I/O options are similar to those in the ViewSonic. The biggest difference is that the Emerge devices have no Ethernet ports. (The LongView Extender has a 15-pin, plus keyboard, mouse, and audio.)
Avocent is best known for its KVM interfaces that offer monitoring and keyboard/mouse control of remote computers, and both the LongView Extender and the Emerge Wireless Media Streamer are logical extensions of that expertise. Historically, of course, most of those KVM switches have been wired analog interfaces. Going wireless means converting those analog signals into digital data for 802.11a transport. And because of the huge amount of data involved, that necessarily means compressing the data for reasons of both practicality and efficiency.
Since the LongView targets traditional computer monitor integration, its compression is optimized to maintain the sharp lines of computer text and spreadsheets, and the graphics and generally limited colors of software application interfaces. The refresh rate is fast enough to track mouse and keyboard changes, but you'll definitely see a lag if, for example, you try to drag a window around the desktop.
That latency is fine in most cases if you're looking at a computer desktop, but it's a serious problem if you're trying to view motion video where fields change every 1/60th of a second. The LongView Extender actually can display video without frames being dropped, but video image quality suffers significantly. The Emerge solution, on the other hand, uses compression designed to maximize video image quality: specifically MPEG-2, which uses temporal compression in addition to spatial compression.
Setting up the Emerge transmitter and receiver couldn't be easier. You plug them in, make your AV connections, if necessary depress a button so the two can “find” each other, and you're moving video and audio wirelessly. It's very simple, although I did have some difficulty making wireless connections over longer distance and through walls. Avocent's specs read up to 250ft. through walls and up to 1000ft. line-of-sight. However, I had trouble with as little as 100ft. through walls. I should note that the same 100ft. and walls give my wireless network a little trouble too, although the signal does tend to re-establish itself. That's less critical with small amounts of email data, but more critical with streamed video.
WIRELESS VIDEO OUTPUT
When you start compressing images, particularly video images, there's always the likelihood of losing image quality. With the MPEG-2 compression on DVDs, most people won't notice the artifacts, but that's a result of a very clean source encoded by quality encoding engines. The Emerge Media Streamer, however, has only analog video inputs through modest-quality RCA component jacks, and that begets a noisy signal. Visually, that shows up as a bubbling kind of effect in otherwise solid color, or light gradients in areas like background walls, skies, and landscapes. If you've seen examples of MPEG compression from noisy sources, Emerge video will look familiar.
The Emerge does reproduce saturated colors reasonably well, and that makes vibrant and richly colored scenes look good. However, there is an unevenness in the color temperature over a range of grayscales, moving noticeably toward magenta in the darker grays and, thus, darker scenes. There is also an inherent softness to the video, although that's really to be expected. For example, Emerge can display up to 1366×768 through the 15-pin RGB port, but if you send a computer signal you'll see a significant softness in sharp lines. Of course, if that's your application, the LongView Extender uses more appropriate compression and is the better solution. Softness in video is generally a less severe flaw, relatively speaking.
Overall, the Emerge Media Streamer does solve a potentially important problem: moving video from one place to another without an unsightly amount of cabling. Even with the modest image-quality loss, Emerge can be a real boon for situations in which moving and viewing content is critical. For those utilitarian purposes, the ability to go wireless certainly outweighs the caveats.
Company: Avocent www.av.avocent.com
Product: Emerge WMS1000
Pros: Eliminates unsightly cables, good color reproduction
Cons: MPEG-2 compression introduces softness to moving images.
Applications: Video installations where cabling is undesirable.
Price: $645 for transmitter; $545 for receiver
Rated Power 5W (transmitter), 4W (receiver)
Dimensions (H×W×D) 1.25"×4"×6.5"
Computer Video I/O VGA, SVGA, XGA, WVGA, and WXGA via mini D-sub 15-pin
Video I/O Component, S-Video, composite video, 480i at 30fps
Refresh Rate Up to 70Hz vertical
Audio I/O Stereo mini-jack
Control Input RS-232 D-sub 9-pin Distance 250ft. through three walls; up to 1000ft. line-of-sight
Communication Modes Point-to-point; multicasting to eight receivers
Security Advanced Encryption Standard (AES)
Antennas Two 2dBi omnidirectional (standard); high-output 8dBi directional (optional)
Accessories Power supply, power supply mount, rackmount (optional)
Warranty Two years
Power Supply External, 9V at 1amp AC to DC universal
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