Bandwidth Reduction

What is Bandwidth Reduction

Bandwidth refers to the maximum rate at which data can be transmitted over a network or internet connection. It is typically measured in bits per second (bps) or multiples, such as kilobits per second (Kbps), megabits per second (Mbps), or gigabits per second (Gbps).

Many people often confuse bandwidth with what we commonly refer to as internet speed, but they are actually two different concepts. If we compare data transmission in a network to a road, the data would be the vehicles on the road, while bandwidth represents the width of the road, and internet speed is the speed at which the vehicles are traveling.

Bandwidth is limited, and within a certain range, devices connected to the same local area network (LAN) share the available bandwidth capacity. This means that for households or businesses, to allocate enough bandwidth for devices that require higher bandwidth, such as video players or computers, it's necessary to reduce the bandwidth used by other devices, such as security systems.

Bandwidth reduction in security surveillance requires a balance between bandwidth and quality. It refers to the strategies and technologies used to minimize the bandwidth consumed by security cameras and surveillance systems while maintaining the quality of video and data transmission. This is crucial in environments where multiple cameras operate simultaneously, as large amounts of data could potentially overwhelm the network.

How to Calculate the Bandwidth Required for Security Cameras?

Calculating the bandwidth required for cameras is quite complex, but we can roughly use the following formula:

Bandwidth (Mbps) = Bitrate (Main) * N + Bitrate (Sub) * M

• Main Stream: Used for high-definition recording with higher resolution and bitrate.

• Sub Stream: Used for real-time preview or viewing video under bandwidth constraints, with lower resolution and bitrate.

• N and M: Represent the number of IP cameras using the primary stream and sub stream, respectively.

In the formula, bitrate refers to the amount of data transmitted per unit of time, typically measured in bits per second (bps) or its multiples (such as Kbps, Mbps). Bitrate is determined by several factors, including video resolution, frame rate, compression method, content complexity, and encoding settings. Different scenarios and requirements will result in different bitrates, and proper bitrate settings can optimize bandwidth usage while ensuring video quality.

How to Achieve Broadband Reduction

In order to optimize the bandwidth usage of security cameras and improve the overall efficiency of the surveillance system, you can start from the following aspects:

1. Select H.265 Video Compression Codecs

H.265 (HEVC, High Efficiency Video Coding) video compression codec can improve the compression efficiency by about 50% compared to H.264, and about 75% compared to MJPEG. The more advanced compression algorithm of H.265 is able to retain video details and reduce compression artifacts more effectively, thus providing clearer and more realistic video images, which can reduce bandwidth and storage requirements while maintaining high quality video performance.

2. Use the Right Resolution

Video resolution directly affects the bit rate of the video. It is important to choose the right resolution for your surveillance needs. For example, if you don't need very detailed images, you can choose a lower resolution (e.g. 720p) to reduce bandwidth consumption. The Sub Stream type, typically used for low-resolution video streams, can be used when accessing an IP camera or recording video, which helps to reduce bandwidth usage without compromising the quality of the main footage.

3. Reducing Frames Per Second (FPS)

FPS refers to the number of image frames captured per second. Lowering the frame rate reduces the amount of data that needs to be transmitted per second. For example, reducing the frame rate from 30 FPS to 15 FPS can cut bandwidth requirements in half. Although reducing the frame rate may affect the smoothness of the video, in many surveillance scenarios, a moderate reduction in frame rate is acceptable to save bandwidth.

4. Setting Motion Detection Recording

Motion Detection Recording is a smart recording mode that starts recording only when the camera detects motion. In this way, bandwidth and storage space are consumed only when there is actual activity taking place. This approach significantly reduces unnecessary data transfer and storage requirements and improves bandwidth utilization.

5. Using Wide-angle PTZ Security Cameras

Wide-angle PTZ (Pan-Tilt-Zoom) cameras are able to cover a larger surveillance area, reducing the number of cameras required. With a wide-angle PTZ camera, the same area can be fully monitored with fewer devices, thereby reducing bandwidth requirements and system complexity. By doing so, the bandwidth requirements of the cameras can be effectively reduced, thus optimizing network performance and the overall efficiency of the surveillance system.

FAQs

1. How much data does a security camera use per month?

The amount of data used by a security camera each month depends on the camera's resolution, frame rate, compression method, and the number of hours worked each day. For example, for a 1080p camera recording at 15 frames per second (fps) with medium compression (H.265), continuous recording could require approximately 648GB of data per month. If the camera is set to record only when motion is detected, such as in battery-powered security cameras, the data usage will be significantly lower.

2. What is the input bandwidth of an NVR?

The input bandwidth of an NVR (Network Video Recorder) refers to the maximum amount of data it can receive and process. This value depends on the NVR's model and design. For typical home or small business NVRs, the input bandwidth ranges from about 80 Mbps to 200 Mbps. Higher-end enterprise-level NVRs may support even higher input bandwidth, up to 320 Mbps or more. The input bandwidth of the NVR directly determines how many cameras it can support, as well as the resolution and frame rate of those cameras.

3. What is the average bandwidth of security cameras?

The average bandwidth of a surveillance camera depends on its configuration, including resolution, frame rate, compression method, and the complexity of the scene. For example, a 1080p camera using H.265 compression at 30 frames per second typically requires around 3-4 Mbps of bandwidth. If H.264 compression is used under the same conditions, the bandwidth might increase to 6-8 Mbps. Therefore, different configurations and usage environments will lead to varying bandwidth requirements.

4. Do security cameras affect internet speed?

Yes, IP cameras consume network bandwidth, which can potentially affect internet speed and slow down the network. If there are many cameras or if the bandwidth demand is high—especially when using high resolution and high frame rate settings—the cameras can occupy a large portion of the bandwidth, leading to slower network speeds for other devices. Therefore, it is crucial to plan network bandwidth carefully and use high-quality routers or network switches to ensure overall network performance. If bandwidth is insufficient, bandwidth optimization measures may be necessary, such as using H.265 codecs, lowering resolution, and reducing frame rates.