중국의 특정 제조사(DAUHA)의 고유 기술등의 내용등이 포함되어 있지만 H.265 CODEC등을 통한
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O MEET THE CHALLENGES of ever-increasing deployments of high-resolution video surveillance systems, High-Efficiency Video Coding (HEVC), or H.265, is quickly moving to the forefront of the industry. The greatest strength of H.265 technology is higher compression rates that reduce the design flow rate in order to lower the cost of storage and transmission.
H.265 implements the advanced techniques to increase bit-stream rates to promote coding quality and to create an enhanced relationship between time delay and algorithm complexity to achieve the best optimizations.
Video surveillance manufacturers are layering their own compression algorithms on top of industry standards like H.265. The goal is to optimize storage and bandwidth by recording higher-resolution video only where certain activities are detected. If nothing is happening within a scene except trees swaying, video data might be captured in low resolution. But if humans or cars are detected, those frames might be recorded in higher resolution.
Dahua Technology is an example of a vendor that is transitioning its video surveillance portfolio to ensure its products are future-proofed when the industry and end customers are ready to fully embrace this latest compression standard. As of November 2016, all of Dahua’s new product releases included dual codec support for H.265 and H.264 for backwards compatibility. Additionally, some products now include Smart H.265+, featuring a collection of intelligent encoding algorithms developed by Dahua as an optimized implementation of the H.265 standard, offering an additional bandwidth savings of 20-30% as compared to standard H.265 compression.
To ensure the standard can be used in products across different platforms, Dahua has built flexibility into Smart H.265+. Operators can configure the codec to tailor the encoding for a particular application or scene, adding flexibility and sophisticated image enhancement. Smart H.265+ technology is said to reduce bitrate and storage requirements by up to 80% compared to H.264 video compression, vastly improving the overall system capital expenditure (Capex) and operating expenditure (Opex).
Let’s take a deeper dive into Smart H.265+, which uses a scene-adaptive encoding strategy, dynamic group of pictures (GOP), dynamic region of interest (ROI) andintelligent noise reduction to deliver high-quality video without straining the network.
HIGHER EFFICIENCY, LOWER COSTSTypical video surveillance applications require 24/7 recording, consuming a large amount of storage space. With the push to HD/UHD video resolutions with high bitrates, recording and storing surveillance video has become one of the main challenges facing the surveillance industry. The cost of transmitting large amounts of data while maintaining video quality and storing this data has exploded, increasing the cost of the entire surveillance system.
To resolve these issues, many manufacturers are continually investing in new technologies and innovations to reduce the cost of video surveillance systems. Vendors can achieve cost savings by upgrading their product lines to support the latest encoding standards (including MPEG4, H.264 and H.265) to take advantage of the improved transmission rates and reduced storage rates that these high-efficiency encoding standards offer.
Incorporating these standards, however, usually required a hardware update, and it took time for manufacturers to introduce the latest standard to the market. In addition, development and adoption of a more efficient standard could take a significant, undetermined amount of time. With more and more devices running the H.265/HVEC standard, only time will tell when the next standard will be available.
In order to stay ahead of the curve, Dahua elected to bring to market a suite of software enhancements to H.265 prior to it succeeding H.264 as the recognized industry-wide standard. To take advantage of these supplemental algorithms, customers need only perform a simple software upgrade on a device running H.265. Following are explanations for these key improvements.
Scene-adaptive encoding strategy — A typical surveillance scene is not fixed; the scene is constantly in flux even though these changes may be imperceptible to human vision. According to the Just Noticeable Difference (JND) model, human vision requires a certain amount of change to an object in order for a difference to be noticeable.
The way human vision perceives an object depends on several factors. For example, the human vision perception is more sensitive to changes to indoor scenes than to outdoor scenes. Humans perceive an indoor scene transmitted at a 4-megapixel (MP) bitrate in the same way as an outdoor scene transmitted at a 1MP-2MP bitrate.
Smart H.265+ technology adopts an encoding strategy that takes advantage of this difference in human perception to improve encoding efficiency. Scene-adaptive encoding implements a differentiated strategy based on smart scene analysis that includes the consideration of light, noise, motion conditions and enjoinments. Scene-adaptive encoding is designed to not only ensure the human vision perception of the surveillance scene, but also improve the encoding efficiency
Dynamic ROI — Surveillance operators are more interested in moving objects in the surveillance scene and less interested in the background area. With this background in mind, Smart H.265+ implements the strategy of automatically separating the moving objects in the scene from the background according to the motion in the video scene through video analytics technology.
After separation, Smart H.265+ adopts varied compression levels according to different regions of interest. Typically in surveillance videos, moving objects appear only in a specified period and last only for a short time. Smart H.265+ may increase the compression level for a background area and reduce the compression level for moving objects, thereby enhancing compression efficiency.