How to achieve high-quality videos with low bandwidth

The bit rate can be reduced, in particular, due to noise reduction. Noise is quite a damaging factor causing clogging of the encoding process. It leads directly to an increase in the bit rate.

Optimize bitrate to reduce streaming

The classic noise reduction systems are of two types. Spatial noise reduction techniques are applied within the frame to help reduce noise, while temporal noise reduction averages the pixels over multiple frames. These are very effective techniques for still images, but they can cause problems when there is movement. In the event that temporary noise reduction is applied to a moving image, a ghost image may appear.

By combining spatial and temporal noise reduction with the ability to dynamically adjust them based on lighting levels and the detection of moving objects, we obtain images with low noise, maximum detail and low bit rate. The bit rate can be optimized by adjusting the amount of noise reduction based on the analysis of important moving objects in the surveillance camera’s field of view. When there is no movement, the bit rate is kept to a minimum. If an important object is detected, the bit rate increases, allowing you to capture as much detail as possible. The result is that the network bandwidth requirements remain low until something major happens in the frame.

Other ways to reduce the bit rate
For some megapixel surveillance cameras, the bit rate is limited by default. Constant bit rate is often used for this. The constant bit rate is kept at a fixed level. This can result in a consistently high bit rate, and setting a low bit rate can result in poor image quality.

In contrast, a variable bit rate preset a certain level of image quality that is maintained regardless of whether there is movement in the frame or not. The bit rate will change depending on the shooting conditions and the presence of motion.

Dynamic noise reduction, as described above, works on the same principle as variable bitrate, but with the addition of intelligent decision-making capabilities based on the presence or absence of motion. This can reduce the bit rate by 50 percent over the standard variable bit rate in non-motion scenes.

Priorization
In addition to reducing noise, prioritization can help lower bit rates. By setting priority areas, you adjust the level of compression for different parts of the image. Multiple areas can be marked on the image, each of which is assigned compression level parameters. A less important area can be configured to use a higher compression rate and therefore a lower bit rate, while important areas can be assigned a lower compression rate to display in more detail.

Take video surveillance at the entrance of a building, for example. Some parts of the image showing the sky can be considered unimportant for better compression. The area of ​​the entrance to the building can be marked as important and assigned a lower compression ratio to ensure recognition of facial features and other identifying details. Finally, the driveway can be defined as a zone with normal compression.

Reduce costs with dynamic noise cancellation
The combination of noise reduction and image area prioritization produces measurable results. The key benefit of this combination is that you get a significantly lower bit rate without losing image quality. A lower bitrate, in turn, reduces bandwidth and memory usage.

Take, for example, a shopping center with a video surveillance system with 200 surveillance cameras installed throughout the premises inside and outside the facility. Let’s say the mandatory requirement for 1080p HD video surveillance cameras is to record continuously for 12 hours a day and once the mall closes, they can only record when motion is detected. In this case, storing video recorded at a rate of 10 frames per second will require almost 70 TB, allowing you to store it for 30 days. The introduction of surveillance cameras that use dynamic noise reduction can save more than 7 TB of required storage capacity. This translates to over $ 10,000 depending on the storage devices used …. Additional savings can also be achieved by adding priorities in certain areas, which will further reduce the bitrate.