The first NAS server I've run into that features a surveillance system is the Synology DS107+, and I was very impressed. Thursday, D-Link announced two NAS servers that work more like Internet-based surveillance products--or network video recorders (NVRs)--than storage devices. They are the DNS-722-4 and the DNS-726-4.
Both products are based on D-Link's two-bay network-attached storage (NAS) device technology, such as that used in the DNS-323. The DNS-726-4 NVR Pro version works with D-Link, as well as Axis, Sony, and Panasonic network cameras, while the DNS-722-4 NVR works only with D-Link network cameras.
There's one more difference between the two. The DNS-726-4 supports multiple channel playback. The DNS-722-4, on the other hand, supports only one channel.
According to D-Link, the new NVRs can house up to two SATA hard drives in four RAID setups and feature a security lock, 24-7 recording, and a friendly graphical user interface for multiple camera management and for viewing live video or playing back recorded data through the Internet from anywhere at anytime.
While many NAS servers can support Internet cameras to form a surveillance system, D-Link's new NVRs reportedly feature an advanced and flexible event-based management mechanism. The NVRs can monitor all camera events via motion detection or digital input and command different cameras to perform tasks based on certain predetermined conditions. For example, if camera 1 detects motion, the NVR can trigger camera 2 to record, camera 3 to emit light, and camera 4 to turn to the preset position.
Other than that, they both boast the following additional features:
- Smart search: The NVRs' intelligent search function quickly retrieves data by finding a selected area on the video based on preset search criteria (motion detected, object missing, focus lost, camera occlusion, etc.)
- Multiple channel playback (available in the DNS-726-4 only): This means that after selecting the desired video period, the NVR will begin playback and display up to four simultaneous channels.
- Playback speed control: Both NVRs can playback at up to 16x speeds in fast-forward or fast-backward modes. They can also playback video one frame at a time.
- Video enhancement: Users can adjust the recorded video to get enhanced output for brightness, sharpness, etc.
- Camera status display: Both NVRs will produce a status page to show connection, recording, frame, and bit rate information for each camera. Users also can check the display to see how much recording time remain.
According to D-Link, the new NVRs are the only IP surveillance recording and playback management systems that offer advanced functionality and four built-in levels of RAID, as well as up to 120 frame speed performance, for less than $700.
But not by much, the DSN-726-4's estimated price is $699.99, while the DSN-722-4 is $399.99. Both will be available during first quarter 2009.