HD and Ultra HD (4K) CCTV – Bandwidth and storage monster

It looks like the next benchmark for video surveillance cameras is going to be the Ultra HD standard, with a resolution of 3840 x 2160 – around 8MP – commonly referred to as 4K.

image size standards

Obviously, there are advantages and disadvantages of 4K technology. A major advantage is the extended picture resolution and ability to reduce the number of cameras covering a defined area.

cctv resolution comparison

The major disadvantage is the bandwidth required for the high resolution.

Typically with high resolution cameras, to manage the excessive network bandwidth usage and storage consumption, an aggressive bitrate limit is imposed. This negates the advanced of the high resolution camera by over-compressing the image introducing significant artifacts.

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What are Bit Rates?

Let’s start with what a bit is. A bit is an acronym for “binary digit,” the smallest possible unit of information in digital computing. It takes 8 bits to make a byte of information. Bit rate refers to the number of bits of data transferred in a file over a set length of time. It’s the combination of video and audio streams in a file, and is commonly measured in number of bits per second.

Constant bit rate (CBR) and variable bit rate (VBR) are the main types of bit rate encoding. Scene complexity can vary significantly over several hours of recorded surveillance video, and the bit rate you select for recording will have an effect on image quality and bandwidth consumption.

A complex scene with moving action, such as traffic on a city street, or a scene with a lot of contrasting colors, will affect image quality and bandwidth consumption more than a less complex scene, such as an interior wall or hallway with very little action or movement.

Constant Bit Rate (CBR)

With constant bit rate encoding, a fixed bit rate and bandwidth is used throughout the entire track or encoded video file. With a constant bit rate, image quality may fluctuate over the course of the video stream because some pieces of content are more difficult to compress than others.

In order for the bit rate to remain constant, the video may be encoded with fewer bits in some places or more bits in other places—resulting in inconsistent image quality. Since bandwidth consumption with constant bit rates does not vary, the file size is limited and more predictable than with variable bit rates.

Pre-planning your security video storage requirements is easier with constant bit rate because the amount of data being recorded never changes. But this is at the cost of image quality at periods of high scene activity.

Variable Bit Rate (VBR)

With variable bit rate encoding, a changeable bit rate and bandwidth is used throughout the encoded video file. The variability of bit rates allows for video to be recorded at a lower bit rate when the detected scene on screen is less complex and at a higher bit rate when the detected scene is more complex.

Complex scenes (such as moving traffic) require more data and greater bandwidth to maintain image quality level than less complex scenes such as a wall or hallway with very little movement or action. With variable bit rates, the quality of video is higher and more consistent throughout the video stream compared to constant bit rates, yet the file size is less predictable.

Image quality is better with variable bit rates than with constant bit rates, yet pre-planning your security video storage requirements is more difficult because the bit rate changes and more complex scenes will require greater bandwidth and storage. The down side is at periods of high scene activity your networks and storage need to be able to cope with excessive demands.

Is there a better way? Yes, a far smarter way!

smart-way

Yes, using our data-centric approach to video. Our systems at Silverstar Analytics allows you to use the highest quality video, without the excessive cost and complexity to your networking and storage infrastructure. We do this, by retaining the vast majority of video at the edge, either on or close to the camera itself. We prefer cameras with their own local storage, meaning that no video is streamed across the network and no separate storage is required. Our system using advanced data analytics to determine the 1% of video that is relevant to your business and copies this, in a network friendly way, to our cloud infrastructure for viewing.

think differently

What does this mean in practice? We have broken the industry wide dependency between high quality video and expensive network upgrades and large storage systems.

We support 4K cameras at the highest quality settings on low grade networks ( less than 1Mbps) with no additional storage requirements. Read more at http://www.silverstaranalytics.com/.

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