In August last year, Ericsson launched the first H.265 codec, and just six months later, the ITU officially approved the HEVC / H.265 standard. The standard is called efficient video encoding ( High Efficiency Video Coding), compared with the current H.264 standard has a considerable improvement. H.265 is designed to transmit higher-quality network video under limited bandwidth. Only half of the original bandwidth is needed to play the same quality video. This also means that our mobile devices (mobile phones, tablets) will be able to play full HD (1080P) video directly online. The H.265 standard also supports 4K (4096 & TImes; 2160) and 8K (8192 & TImes; 4320) ultra-high-definition video. It can be said that the H.265 standard allows network video to keep up with the "high resolution" of the display. Within a few months, you can see that devices that support H.265 decoding are available (such as smartphones, graphics cards, etc.). H.264 has dominated the past five years, and in the next five or even ten years, H.265 is likely to become mainstream. Why is H.265 better than H.264 Before discussing the enhancements and advantages of H.265, let's first take a look at H.264. H.264, also known as MPEG-4 AVC (Advanced Video Codec), is a video compression standard and a widely used high-precision video recording, compression, and distribution format. H.264 is famous because it is a codec standard for Blu-ray discs. All Blu-ray players must be able to decode H.264. More importantly, because Apple decided to abandon Adobe's VP6 encoding and chose H.264, this standard has entered hundreds of millions of households with hundreds of millions of iPads and iPhones, becoming the current video encoding field. Absolutely overlord, occupying more than 80% of the share. H.264 is also widely used in network streaming media data, various high-definition TV terrestrial broadcasting and satellite television broadcasting. Compared with previous coding standards, H.264 has some new features, such as multi-reference frame motion compensation, variable block size motion compensation, intra-frame prediction encoding, etc. By using these new features, H.264 has more than other coding standards Higher video quality and lower bit rate have also been recognized by people. The coding architecture of H.265 / HEVC is roughly similar to that of H.264 / AVC, mainly including: intra prediction (intra predicTIon), inter prediction (inter predicTIon), transform (transform), quantization (quantization), Deblocking filter, entropy coding and other modules. But in the HEVC coding architecture, the whole is divided into three basic units, namely: coding unit (CU), prediction unit (PU) and transform unit (TU). Compared with H.264 / AVC, H.265 / HEVC provides more different tools to reduce the bit rate. In terms of coding units, the size of each macroblock (MB) in H.264 is fixed at 16x16 Pixels, and the coding unit of H.265 can be selected from the smallest 8x8 to the largest 64x64. Take the following picture as an example, the area with little information (the color change is not obvious, such as the red part of the car body and the gray part of the ground) is divided into larger macroblocks, the encoded codewords are less, and the details are more ( The macroblocks divided by tires are correspondingly smaller and more, and there are more codewords after encoding, which is equivalent to focusing on encoding the image, thereby reducing the overall code rate, and the coding efficiency is correspondingly improved. At the same time, H.265's intra prediction mode supports 33 directions (H.264 only supports 8), and provides better motion compensation processing and vector prediction methods. Repeated quality comparison tests have shown that under the same image quality, the video size encoded by H.265 will be reduced by approximately 39-44% compared to H.264. Due to the different measurement methods of quality control, this data will also change accordingly. The data obtained through subjective visual testing shows that the quality of H.265-encoded video can be similar to or even better than H.264-encoded video when the bit rate is reduced by 51-74%, which is essentially more The signal-to-noise ratio (PSNR) is better. The evaluation criteria of these subjective visual tests cover many disciplines, including psychology and human visual characteristics. The video samples are very extensive. Although they cannot be used as final conclusions, they are also very encouraging results. Compared with the subjective visual test of H.264 and H.265 encoded video, we can see that the bit rate of the latter is greatly reduced compared to the former The current HEVC standard has three modes: Main, Main 10 and Main Still Picture. Main mode supports 8-bit color depth (that is, 256 shades of red, green, and blue colors, totaling 16.7 million colors), and Main 10 mode supports 10-bit color depth, which will be used on UHDTV. The first two restrict the chroma sampling format to 4: 2: 0. It is expected that the standard will be expanded in 2014, and will support 4: 2: 2 and 4: 4: 4 sampling formats (ie, provide a higher degree of color reproduction), and multi-view coding (such as 3D stereo video coding) . In fact, the H.265 and H.264 standards have some overlap in various functions. For example, the Hi10P part of the H.264 standard supports 10-bit color depth video. Another part of H.264 (Hi444PP) can also support 4: 4: 4 chroma sampling and 14 deeper features. In this case, the difference between H.265 and H.264 is that the former can use less bandwidth to provide the same function at the cost of device computing power: H.265 encoded video requires more computing power To decode. At present, a chip supporting H.265 decoding has been released-Broadcom Corporation of the United States (Broadcom) released a Brahma BCM7445 chip at the CES exhibition in early January this year. It is a quad-core processor using a 28-nanometer process. Can simultaneously transcode four 1080P video data streams, or parse the H.265 encoded UHD video with a resolution of 4096 × 2160. The future of H.265 For ordinary consumers, what is more concerned about is how long it will take to buy a device that supports H.265 / HEVC decoding. This depends on many factors. Graphics giants such as AMD and Nvidia may integrate H.265 in a relatively short period of time, although H.265 has many new features that have not yet been added. The first-generation chip may only be applicable to the standard that has just been finalized. After the future expansion is completed, a version that supports H.265 multi-view decoding will also be made. Since different companies have different decoding capabilities for H.264 video, in terms of device-level compatibility, we may see some "fooling people" information. For example, those smartphones or tablets that are powerful enough to force H.265 video decoding through computing power can be advertised as "support H.265 video decoding", and such "support" will make them deal with The power consumption during video has increased dramatically. There will definitely be some unscrupulous companies that hyped up H.265 and used this new video standard as a device-level gimmick, so that you can sell videos that do not really support H.265 decoding to consumers who do not know the truth . In fact, these contents will be produced by major media and advertising companies, so the inside story is more complicated. At present, the main use of cable TV and digital TV broadcasting is still the MPEG-2 standard. The good news is that the introduction of the H.265 standard can eventually convince broadcasters to abandon the obsolete MPEG-2. Because of the same content, H.265 can reduce bandwidth consumption by 70-80%. This can easily support full HD 1080P broadcasting under the existing bandwidth conditions. But on the other hand, TV broadcasters have few reasons to want to innovate because most cable companies face limited competition in their target markets. For the purpose of saving bandwidth, satellite TV companies may adopt the H.265 standard first. From a long-term perspective, the H.265 standard will become the choice of 4K and 8K resolutions for UHDTV. But this also brings other problems. Currently, there are very few native 4K resolution video content. The completion of the H.265 standard means that content owners now have a corresponding theoretical standard, but they do not yet have a unified way to deliver content. Sony is planning a 4K movie digital delivery service for customers who purchase Sony 4K TVs, and this year also launched a high-definition Blu-ray DVD player called "Mastered in 4K." These 1080p movies are converted from the 4K digital alphabet version, and in the future, it is expected to launch a "near 4K experience" with better quality. Standard definition (SD), high definition (HD) and 8K resolution ultra high definition (UHD) video size comparison chart The Blu-ray Disc Association is working on ways to support 4K resolution video in the Blu-ray Disc standard, but this is not that simple. In theory, H.264 can have this function after expansion, but then the bit rate problem will surface. An H.264 encoded 4K Blu-ray movie requires much more storage space than the H.265 version of the same content, and its size can be as high as 100G or more, and existing players also do not support 100-128GB high-capacity recordable and rewritable Compact disc (BDXL). So far, there is still no proper solution to add 4K resolution video to the existing Blu-ray standard without compromising its compatibility. Although updating to the H.265 standard does not require improvement of the disc manufacturing process, it requires the manufacture of a brand new player to play the new Blu-ray disc. Although some players can now play high-density discs, it also requires Only need to check and upgrade the equipment. Another big problem is the support of the game console for the H.265 standard. Sony ’s PS2 and PS3 consoles have driven the development of DVD and Blu-ray standards. The upcoming PS4 is likely to support 4K resolution content in theory, but how should 4K resolution video be transmitted, and through which standards? This is still under discussion. At present, we still need to be cautiously optimistic about the H.265 / HEVC standard. But one thing is certain: the H.265 standard will significantly reduce bandwidth consumption at the same content quality. With H.265, HD 1080P TV broadcasts and 4K video network playback will not be difficult, but only if Sony or other media Giants can figure out ways to deliver this content. At the same time, if the mobile device is to adopt the H.265 standard, its high power consumption when decoding video is also a problem that major manufacturers need to solve Solar Landscape Lights,Solar Lawn Lights,Solar Powered Yard Lights,Solar Powered Landscape Lights Jiangmen Biaosheng Solar Energy Technology Co., Ltd. , https://www.bsprosolar.com
