H.265 is a new video coding standard established after ITU-T VCEG followed by ITU-T VCEG followed. The H.265 standard surrounds the existing video coding standard H.264, reserves the original technologies, and improves some related technologies. New technology uses advanced technology to improve the relationship between code stream, coding quality, delay and algorithm complexity, reaching optimization settings. The specific content includes: increasing compression efficiency, reducing real-time delay, reducing channel acquisition time and random access delay, reducing complexity, and the like. H.264 Due to the algorithm optimization, the standard clearance digital image transmission can be realized at a speed of less than 1 Mbps; H.265 can realize the transfer of 720P (resolution 1280 × 720) of the transmission speed of 1 to 2 mbps.
H.265 Technology (Type) Analysis
H.265's research and development purposes can be seen from naming, H.265, HEVC (High Efficiency Video Coding, High Efficiency Video Coding), the most important use is to further reduce the flow required to reduce the storage Cost of transmission. H.265 Requirements In the best coding template, the H.264 compressed 1080p monitoring video 36% is saved by 36% of the amount of information compressed by H.264, and it will be almost in the image quality. The savings will be further improved to 50%.
In addition, H.265 is aimed at compression and decompression, the time required to decompress the H.265 encoding, only 10% encoded by H.264, and decoded time It can be 60%.
What is the advantages and differences between H.265 and H.264?
Algorithm complexity relative to H.264, H.265 has greatly improved, with this better compression performance. H.265 has made a large improvement in many characteristics (as shown in Table 1).
In combination, the technical highlight of H.265 is:
Flexible encoding structure: In H.265, the size of the macroblock is extended from H.264 to 16 × 16 to 64 × 64 to facilitate the compression of high resolution video;
Flexible block structure - RQT (Residual Quad-Tree Transform). RQT is an adaptive transformation technology that extends and extension of the ADAPTIVE BLOCK-SIZE TRANSFORM technology in H.264 / AVC. For interframe encoding, it allows the size of the transform block to adaptive adjustments according to the size of the motion compensation block; for intra coding, it allows the size of the transform block to adaptive according to the characteristics of the intra predicted residual. adjust. Big block transformations can provide better energy concentrations with respect to small blocks, and can save more image details after quantification, but on the other hand, there will be more ringing after quantification. effect. Therefore, according to the characteristics of the current block signal, the adaptive selection variable change block size can be obtained by the energy concentration, the degree retention level, and the rings effect of the image.
Sample adaptive offset. SAO is in the codeca, after DEBLOCK, by the classification of the reconstructed image, add an offset to each type of image pixel value, reducing the purpose of reducing distortion, thereby increasing the compression ratio, reducing the code stream. After SAO, the average can reduce the code stream of 2% to 6%, while the performance consumption of the encoder and decoder has only increased by about 2%;
Adaptive Loop Filter. The ALF is used to restore the reconstructed image after the DEBLOCK and SAO are in the DEBLOCK and SAO, and the minimum difference (MSE) is minimized between the reconstructed image and the original image. The coefficient of ALF is to apply ALF in frame-level computing and transmission, or may perform ALF based on blocks or quadtree, and if it is based on part of the ALF, it is necessary to pass indicator area information. Additional information;
Parallelization design. The current chip architecture has gradually developed from single nuclear performance, so that in order to adapt to a very high degree of parallelization, HEVC / H.265 introduces many parallel operation optimization ideas.
Comparison of H.264 and H.265
H.265 technology development (bottleneck and future development trend) analysis?
In the monitoring industry, H.265 has been supported by a number of chip program providers, but from the actual market, it is still very small to use H.265. If the item has been completed, replace the network camera of H.265, then the corresponding backend storage also needs to be replaced with a product that supports H.265. In this way, the overall project transformation is too large.
For new projects, H.265 is still a new technology, and each security manufacturer basically integrates H.265 into its high-end product line, so the overall cost of new projects is also higher than the equipment using H.264.
In fact, from the entire surveillance industry layout, it is more suitable for use in H.265 to have a need such as 4K / 8K. Higher sharpness, lower bandwidth. With H.265, the original bandwidth can be reduced by at least 50%, whether it is network transmission, or a rear-end storage space can be greatly helpful.
At the same time, there is a message on the network that the Microsoft Windows 10 operating system has built-in HEVC (high efficiency video coding, or H.265), which can directly play 4K or 8K videos directly through the Windows 10 system.
As a new generation of video coding technology, H.265 has a few generations of coding technologies such as MPEG-4, H.264 and other unparalleled advantages, that is, there is currently no compression technology that competes with it, there is also a very compatibility. Big advantage. In short, H.265 will greatly promote the rapid development of video applications including HD video.
This article is transferred from D1NET (reproduced)
Related Resources: HEVC_Code Rate Control Unit Division Algorithm - Professional Guidance Document
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