Review: AVerMedia AVerDiGi EB1704HB WiFi-4 - Page 3

By Lisa Phifer

February 27, 2009

Looking back

After video has been recorded, there are many ways to play it back. Anyone local to the NVR can use front-panel buttons or the remote control to play, pause, or fast-forward recorded segments on a connected monitor—using the NVR more or less like an ordinary VCR.

Alternatively, recordings can be replayed remotely using a Remote Console program (see below). This Win32 executable can be installed manually from CD or downloaded automatically from the NVR the first time you push the WebViewer’s Remote Console (Playback) button. Like the WebViewer, the Remote Console can be used to preview live video. However, the Remote Console goes much further by enabling network-based video storage and playback.      

 Fig4-RC-Search.jpg                             

  

Fig5-RC-Launch.jpg

Whenever the Remote Console is launched, it prompts for the NVR's User ID and password. Once connected to the NVR, the Remote Console two supports two playback methods:

1)    Video stored on the NVR’s HDD can be played remotely, either by downloading an available time period for immediate playback or by watching a replayed video stream.

2)    Video recorded by the NVR can also be relayed to the Remote Console program as a live video feed, to be duplicated onto that remote host's HDD for local playback in the future.

The first method (remote playback) use the NVR as central storage but results in considerable delay whenever you want to play video back remotely. Just choose a date, hour, and camera of interest, then select from a series of still snapshots which represent available video segments. You can start watching NVR-recorded video during file download, but transfers usually take longer than playback. We thus learned to be very selective when selecting time periods for download.

The second method (local playback) requires the Remote Console program to run continuously while recording to the remote host's HDD—in essence, behaving as network-attached storage. The Remote Console is somewhat picky about storage locations—for example, you cannot designate a USB thumb drive or an HDD without copious free space. But once you have recorded video locally, playback is fast and easy.

Search and find

To this end, the Remote Console offers two extremely handy playback tools: Visual Search and Intelligent Search. During a Visual Search, you wade through still snapshots for available time periods, drilling down into shorter periods until you find the video segment that you're looking for. This is can be very helpful when searching for a recognizable event in a lengthy recording (e.g., a package being dropped at your door sometime last week.) But it can also be tedious.

Intelligent Search helps by detecting occasional motion in an otherwise still area. To perform an Intelligent Search, select an area of a camera pane you wish to analyze. Then click the Intelligent Search button—recorded video plays until the Remote Console spots movement in that area, at which time playback is paused. You can’t use Intelligent Search effectively in a high-traffic or windy outdoor area. But we found it extremely helpful for scanning footage of indoor venues where off-hours movement was unexpected. (Note that Intelligent Search analyzes recordings for motion, independent of camera-triggered Motion Recording.)

During our review, we relied primarily upon the WebViewer and the Remote Console. We also used the included USB Playback Console, a Win32 utility for watching video segments dumped from the NVR to a USB stick. USB playback is essential in cases where the NVR is not network-accessible—for example, video exported for third-party (e.g., legal) review. Exported snapshots and clips are time-stamped and can even be digitally “watermarked” with an overlay image for source verification purposes. However, video files are so large (and writing them to the NVR’s USB port is so slow) that we prefer to use the Remote Console whenever feasible.

We has less luck using the WinCE PDAViewer. According to tech support, this program runs on Windows Mobile 6, but it could not be installed on our WM6 smartphone. When we tried the PDAViewer on an older Pocket PC, the program ran but refused to connect to our EB1704HB WiFi-4 (see right). The PDAViewer sounds sexy and it certainly could be handy in a pinch. But, from a practical standpoint, we think that most consumers will prefer to preview live video on a laptop or perhaps a netbook.

Fig6-PDAViewer.jpg

We also installed the included Central Monitor System (CM3000), a Win32 program designed for multi-NVR installations where security staff monitors up to 1000 distributed locations. We had no trouble connecting our EB1704HB WiFi-4 to the CM3000. But we chose not to review the CM3000 because it lies beyond the average homeowner’s needs or skills.

Finally, none of these supplied programs incorporate Help menus. We found the WebViewer and Remote Console intuitive enough that Help was not really necessary. Nonetheless, Help menus would be a welcome addition to this entry-level bundle.

On the air

Other comparably-priced home surveillance systems exist, but Wi-Fi drew us to the EB1704HB. Tech-savvy consumers might combine their own wireless router with an NVR and third-party IP cameras. This is not rocket science—but it requires more network-know-how than your average homeowner or “Mom and Pop” shopkeeper possesses. The EB1704HB WiFi-4 is designed to fill this gap by completely avoiding Wi-Fi device integration and network setup.

To accomplish this goal, AVerMedia factory-configures bundled Wi-Fi cameras to match the NVR’s embedded 802.11g AP settings. We used a WLAN analyzer (below) to identify our unit’s non-beaconed SSID (EB1704HB_WiFi4_040020) and security policy (AES encryption, WPA2-PSK authentication). Oddly, we also spotted our cameras probing for an enterprise WLAN named AP350—perhaps a network used for camera configuration or testing back at AVerMedia?

Fig7-Analysis_sm.jpg

Click to enlarge.

Note that it is impossible to connect your own desktop, laptop, or PDA to this secure WLAN without knowing the factory-configured PSK. In theory, WPA2 PSKs can be guessed through brute force cryptanalysis. In practice, we doubt that AVerMedia chose a short text passphrase vulnerable to WPA PSK cracker dictionary attack. As a result, the NVR-camera WLAN is private; it cannot be eavesdropped upon or used to carry other traffic (including remote preview or playback traffic).

In fact, AVerMedia intentionally obscures all Wi-Fi settings to discourage end-user modification. When connected via Ethernet, camera web configuration portals can be reached but are password-locked to prevent customer (or hacker) access. Similarly, the NVR’s on-screen display does not expose any of the embedded AP’s network or security parameters. The net effect is to insulate the surveillance WLAN from customer configuration mistakes—or site-specific Wi-Fi tuning.

In the unlikely event that a bundled Wi-Fi camera is lost or damaged, customers must call AVerMedia to request a factory-configured replacement. Upon receipt, the replacement camera must be connected directly to the NVR using a cross-over Ethernet cable; the NVR’s on-screen display menu is then used to invoke an IPCam (re)registration scan. This methodology facilitates field repair, but it also prevents consumers from adding their own after-market Wi-Fi cameras.

Wireless performance

Perhaps more importantly, this closed-system approach makes it difficult to detect or avoid localized RF interference problems.

As shown below, the our surveillance WLAN performed reasonably well, sending mostly mid-size frames with few CRC errors. Positioned at the periphery of a typical 3000 square foot two-story home, three out of four Wi-Fi cameras exhibited solid signal strength. The most distant camera, roughly 100 feet from the NVR, experienced frequent but brief connection losses.

Fig8-Traffic_sm.jpg

Click to enlarge.

This performance is comparable to other residential-grade 802.11g APs. Your mileage will vary, depending upon your own venue’s construction—and the presence or absence of RF interference.

For example, a home with an existing wireless router could encounter RF interference if the EB1704HB WiFi-4 used an overlapping channel. Today, many residential routers seek out cleaner channels on their own. But those that do not would experience degraded WLAN performance following NVR installation. It would be difficult for end users or tech support to diagnose RF interference without visibility into the NVR’s factory-assigned channel.

In our case, the NVR we tested was factory-configured to use channel 13. This unusual assignment interfered just slightly with a neighboring 802.11n AP on channel 11. When we asked AVerMedia how to change this channel, we learned that end-user reconfiguration was not possible. According to AVerMedia, our review unit used a channel between 1 and 13 because it was developed at the company’s headquarters and not changed to the US-defined range (1-11).  The company plans to update firmware on all US EB1704HB WiFI-4 units to revert to the US-defined range in the near future.  (Firmware updates are normally issued on monthly or at least quarterly basis.)

Finally, home and small business WLANs are transitioning rather quickly to 802.11n Draft 2.0. Based on our traffic measurements, the EB1704HB WiFi-4’s surveillance WLAN would not utilize the added capacity delivered by 11n. However, this NVR could benefit from 11n’s improved reach and reliability—even if only the NVR’s AP were upgraded in a future release.

Bottom line

In our experience, the EB1704HB WiFi-4 is a very quick and easy way to roll out an indoor video surveillance system in a smallish venue with no pre-existing WLAN. Unless your venue is brightly lit during recording hours, we recommend springing for the CCD camera bundle.

For users that already have a home or small office WLAN, this product’s turn-key value proposition is not so clear-cut. Here, plug-and-play setup is a time-saver, but not essential. While isolating surveillance traffic on a closed, secure WLAN is still attractive, Wi-Fi-experienced consumers may prefer to have more control over WLAN settings and/or camera selection.

Lisa Phifer owns Core Competence, a consulting firm focused on business use of emerging network and security technologies. She has been involved in the design, implementation, assessment, and testing of NetSec products and services for over 25 years.

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