How do modern video security system designs best tackle the challenges of remote monitoring of high resolution video? Technologies addressing the impact of video transmission on infrastructure and processing video for high performance results bring impactful value to the security marketplace.
Large scale and high camera count video surveillance systems need to be designed with several scalability considerations in mind. At the forefront is bandwidth consumption.
Often larger scale systems require centralized monitoring. Furthermore, many video surveillance systems of any scale benefit from the ability to remotely monitor video, which requires the system design to take into account available bandwidth to transmit live video streams and provide responsive call up of high quality and low latency live video.
Salient’s CompleteView provides Dynamic Video Management. In summary, it contains a suite of unique features that enable a superior video viewing experience.
Dynamic Resolution Scaling minimizes bandwidth consumption intelligently while providing full display quality and full resolution recorded video.
Dynamic Frame Throttling allows CompleteView to handle almost any number of simultaneous user connections for live video streaming even if the system was not designed for maximum possible user load.
Dynamic Video Decoding enables CompleteView to operate while using the fewest possible hardware resources, reducing hardware deployment cost and still providing the rich set of video management capabilities.
These features combine to provide high system scalability by reducing the impact on server hardware and network infrastructure.
Use bandwidth – intelligently!
In short, CompleteView is designed to stream only the amount of video being viewed on screen. Although it may seem like an obvious function of Video Management Systems, the type of design described herein is the exception, not the rule, and corresponding functionality provides great benefits to users.
The majority of video surveillance viewing technologies transmit a higher or lower resolution video feed as compared to the area the video is being viewed on screen. When the video reaches the viewing location the resolution is scaled to fit in the area allocated for display of that video. For instance, if a 5MP camera is being displayed full screen on a 1080P monitor (which is about 2MP of display resolution) only a fraction of the image would appear on screen unless the video is scaled down to fit on the 1080P display. Sending 5 megapixels of video and only displaying 2 megapixels means a lot of unnecessary data is streamed over the network which is ultimately discarded by the display workstation. In this example, the extra data does not improve the display quality and results in greater bandwidth consumption. The effect could be slow call up of video, high processor utilization, higher latency of the video stream, difficulty controlling Pan, Tilt and Zoom cameras and more.
Dynamic Resolution Scaling (DRS) is the intelligent technology minimizing bandwidth consumption when streaming video with CompleteView. DRS provides two key benefits that combine to stream just the video necessary for display.
Video streamed for live display is scaled before being transmitted. This means in the previous example instead of sending 5 megapixels of video to be displayed on a 1080P resolution screen, only 1080P resolution is streamed. This is done without affecting the recorded video, so the full resolution is always available for investigations and export.
Digital PTZ cropping streams only the area within the camera’s field of view being shown on screen. When a user ‘zooms in’ digitally, only a smaller area of the camera’s field of view can be seen on screen. For instance, if zooming in on a car’s license plate, only the license plate is displayed so it can be shown in higher detail within the display area on screen. The car, parking lot and background are cropped out and no longer shown until the user zooms out. Dynamic Resolution Scaling will perform the cropping operation before streaming video to the display workstation so all the background information that will not be displayed is not transmitted over a network. The end result of these capabilities is the user sees on screen the high quality video without the transmission of any unnecessary video data.
Providing maximum performance
Processing video is necessary for a number of operations required for VMS software. Some examples include, displaying video on screen, resizing the resolution, pixel based motion detection, date & time overlay on video and more. The less processing required the lower the server and client hardware costs for the video security system.
At the most basic level an NVR can take in video from cameras, store it to disk and retransmit the video to clients for live display, if clients are connected. These operations take very little processing power, reducing the cost of the NVR hardware; however the processing demand could be placed on client computers in this scenario. Video sent to clients for display will need to be decoded and resized to fit on the screen. Of course, high resolution video requires more processing than low resolution video, increasing hardware costs or leading high latency video display.
Dynamic Resolution Scaling reduces this effect. If the video being received by the camera is too high resolution for display on a client’s screen, it is resized to the correct resolution reducing the processing required to display the video therefore reducing the hardware costs of the client computers.
CompleteView’s Dynamic Video Decoding also aids in reducing NVR hardware costs by dynamically processing video based on the current demand for the video. In the scenario where users are not viewing live video, video is recorded but not processed. When video is requested for display only those requested cameras are processed and the decoding operation takes place just once per camera even if multiple clients require the same video stream simultaneously, further reducing system load and associated hardware costs.
Flexibility for high user demand
In some cases, demand for video can greatly exceed the capacity of the video surveillance system. If a high profile security event is unfolding, monitored equipment breaks or any number of other circumstances occur there could be a spike in unanticipated demand for access to live video.
Dynamic Frame Throttling constantly monitors system performance and detects any processing overload due to live video requests. Affected live video feeds will throttle to a lower frame rate. Recorded video is not altered however a lower frame rate is processed by the NVR and a lower frame rate is streamed to clients so processing load and bandwidth are reduced allowing for a greater number of simultaneously connections to video. When user demand is reduced or system processing capability catches up to the user demand the original streaming frame rate is restored automatically.
Features of the VMS engine itself are often overlooked. System designers are encouraged to check ‘under the hood’ as the features of the recording engine itself can have a big impact on the user experience and success of video security technology deployment.