When it comes to improving the quality of video streams in video surveillance, we cannot fail to mention H.265, the current most efficient video codec technology standard. H.265, also known as HEVC (High Efficiency Video Coding), is a video coding technology designed to greatly reduce the video stream bit rate while maintaining the highest available image quality. Compared with its predecessor technology (H.264), H.265 can provide approximately twice the compression ratio while ensuring the same video quality; or greatly improving the image quality with the same bit stream. Its theoretical maximum resolution reaches 8192*4320, including 8K UHD format.

With the rapid development and large-scale deployment of IPC, the high-definition process of security video surveillance is constantly deepening. The lens specifications of the front-end equipment and the display resolution of the back-end are simultaneously improving, and the video codec standards need to be changed accordingly. .

The advantages of H.265

As the H.265 format enters the market, it has gradually begun to be deployed in high-definition IP cameras and NVR products. H.265 can reduce storage capacity by about 50% due to the improved efficiency of its algorithm. The working principle of the two video coding and decoding technologies of H.265 and H.264 is to find duplicate frames by comparing single video frames. These redundant parts will be replaced with a small amount of substitute data information that can represent the original content. The difference between the two lies in the ability of H.265 technology to enlarge/reduce CTU (coding tree unit) blocks. The CTU size of H.265 is between 4*4 and 64*64, while the H.264 technology only allows CTU blocks with a size of 16*16. For the enhancement of CTU segmentation, as well as better motion compensation and spatial prediction, a large amount of signal processing capability improvement is required.

In addition to using CTU to reduce the code stream, H.265 also relies on parallel computing to make its own encoding process faster. It supports AVX/AVX2, FMA3/FMA4 and other extensions, and the single rectangular areas of the image during the operation are independent of each other, thus supporting parallel processing. H.265 also has a capability that H.264 does not have, namely WPP (Wavefront Parallel Processing) technology, a decision tree technology that can make the compression process more efficient.

In summary, H.265 compression technology is an efficient video coding technology, which has achieved substantial improvements in three aspects compared to its predecessor technology. H.265 technology means smoother video playback, lower latency, and smaller storage space. For the advanced high-definition and intelligent security video surveillance field, better image quality means more space for later intelligent processing and analysis operations; lower code stream and storage space means lower total ownership Cost, technically speaking, the advantages outweigh the disadvantages.

However, H.265 is still far from large-scale deployment. In the long run, H.264 and H.265 should coexist for a long time.

H.265 development obstacles

At present, the obstacles to the development of H.265 technology are largely due to the optimized H.264 technology (currently H.264 is the technical standard available for most scenarios in the industry) and the high upgrade cost. In addition, the reasons that affect the development of H.265 should probably also consider factors in the industrial chain-improving production equipment and processes to produce equipment compatible with the H.265 standard, and patent licensing fees.

▎Limitations of laboratory testing

According to the test of ICT-VC (Joint Collaborative Team on Video Coding), the compression rate of H.265 is doubled compared to H.264, but this is only the laboratory test data, not the actual test. Data, therefore, cannot reflect the complexity of the real environment at all. Therefore, the doubling of the compression performance of H.265 claimed by H.265 at this stage is still at the theoretical value.

On the other hand, H.264 has been used in the industry for more than 10 years, and its performance has been well known by users. It also has the most abundant selection of encoders and decoders. The industry chain has support from chip and board manufacturers. , All aspects tend to be stable.

▎High patent fees

Another issue that hinders the large-scale deployment of H.265 is patent authorization. H.264 has benefited many companies in the industry, and H.265 is not a free new tool. H.265 is not popular at this stage, and its patent ownership problem has not been solved uniformly. The result is high patent costs. For security companies, this is a problem that has to be faced, and it needs to be taken seriously, because it is related to manufacturing and the cost increase for customers: in order to be compatible with new standards, both front and back devices need to be updated and upgraded. The customer is convinced that all the extra expenses are worth it?

Video codec standard development follow-up

The development of video coding and decoding can basically be summarized in a period of 10 years: In 1994, the MPEG2 specification appeared. In 2003, the H.264 standard appeared. In 2013, H.265 appeared.

When MPEG2 appeared, the focus of the industry was mainly on DVD players and SD TVs. MPEG2 can be used in these devices well. Subsequently, the emergence of H.264 meets the needs of IT, mobile Internet, HD resolution, etc., and promotes the development of HD digital TV, Internet video, mobile video, video surveillance, Blu-ray video and other applications. H.265 also has its own abilities, and will be used in ultra-HD scenes, cloud computing and other advanced applications.

With the development and application of H.265, its founding organization ICT-VC established a new team (IVET), focusing on stronger compression technology. At the same time, another organization AOM (Alliance for Open Media) was established, positioning itself to create Internet video standards. Its members include a number of Internet and technology-related companies, such as Microsoft, Google, Intel, Amazon, etc.

For security, the H.265 standard has its technological leadership, but H.264 is more usable and economical at this stage, so there is no global optimal codec standard, only the most suitable standard to meet the needs of the scene. However, it is foreseeable that the evolution of video codec standards will accelerate due to the investment and competition between different organizations. Perhaps the future development of video codec will no longer follow the 10-year development rule, but will enter Faster pace of development.

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