At present, many cameras use H.265 encoding standards. H.264 encoded cameras are gradually decreasing. Why is H.265 popular? What is the difference between H.264 and H.265?
What is H.265
H.265 is a new video coding standard formulated by ITU-TVCEG after H.264. The H.265 standard surrounds the existing video coding standard H.264, retains some of the original technologies, and improves some related technologies. The new technology uses advanced technology to improve the relationship between code stream, encoding quality, delay, and algorithm complexity to achieve optimal settings.
Specific research contents include: improving compression efficiency, improving robustness and error recovery capability, reducing real-time delay, reducing channel acquisition time and random access delay, reducing complexity, etc. Due to algorithm optimization, H264 can realize SD digital image transmission at a speed lower than 1Mbps; H265 can realize the transmission of 720P (resolution 1280 * 720) ordinary high-definition audio and video using a transmission speed of 1 ~ 2Mbps.
H.265 is designed to transmit higher-quality network video in a limited bandwidth, and only needs half the original bandwidth to play the same quality video. This also means that our smartphones, tablets and other mobile devices will be able to directly play 1080p Full HD videos online. The H.265 standard also supports 4K (4096 × 2160) and 8K (8192 × 4320) ultra-high-definition video. It can be said that the H.265 standard has allowed the network video to keep pace with the "high resolution" of the display.
Â
Â
What is H.264
H.264, also the tenth part of MPEG-4, is proposed by the Joint Video Team (JVT, Joint Video Team), which is a combination of the ITU-T Video Coding Experts Group (VCEG) and ISO / IEC Moving Picture Experts Group (MPEG) The highly compressed digital video codec standard. This standard is often referred to as H.264 / AVC (or AVC / H.264 or H.264 / MPEG-4 AVC or MPEG-4 / H.264 AVC), and developers of both aspects are clearly stated.
The advantage of H.264 is that it has a very high data compression ratio. Under the same image quality, the compression ratio of H.264 is more than twice that of MPEG-2 and 1.5 to 2 times that of MPEG-4.
For example, if the size of the original file is 88GB, it will be 3.5GB after compression using the MPEG-2 compression standard, and the compression ratio will be 25: 1, and it will be 879MB after compression using the H.264 compression standard, from 88GB to 879MB The compression ratio of H.264 reaches an amazing 102: 1.
Low bit rate plays an important role in the high compression ratio of H.264. Compared with compression technologies such as MPEG-2 and MPEG-4ASP, H.264 compression technology will greatly save users' download time and Data traffic charges. It is particularly worth mentioning that H.264 has a high compression ratio and high-quality and smooth images. Because of this, H.264 compressed video data requires less bandwidth during network transmission. And more economical.
Â
Â
How is H.265 different from H.264
Before discussing the enhancements and advantages of H.265, let's take a look at H.264 first. H.264 is also called MPEG-4 AVC (Advanced Video Coding, Advanced Video Coding). It is a video compression standard, and it is also a widely used high-resolution video recording, compression, and distribution format. H.264 is famous for being a coding and decoding standard for Blu-ray discs. All Blu-ray players must be able to decode H.264.
More importantly, because Apple resolutely abandoned Adobe's VP6 encoding and chose H.264, this standard has entered millions of households with hundreds of millions of iPads and iPhones, and has become the current video encoding field. Overlord, occupying more than 80% of the share.
H.264 is also widely used in network streaming media data, various high-definition television broadcasts, and television broadcasts. Compared with previous coding standards, H.264 has some new features, such as motion compensation for multi-reference frames, variable block size motion compensation, intra prediction coding, etc. By using these new features, H.264 has more advantages than other coding standards. High video quality and lower bit rates have also been recognized by people and widely used.
The coding architecture of H.265 / HEVC is roughly similar to that of H.264 / AVC, and it also mainly includes: intra prediction, inter prediction, transform, quantization, Deblocking filter, entropy coding and other modules. However, in the HEVC coding architecture, the whole is divided into three basic units, which are: a coding unit (CU), a prediction unit (PU), and a transformation unit (TU).
Why H.265 is better than H.264
Compared to H.264 / AVC, H.265 / HEVC provides more different tools to reduce the bit rate. In terms of coding units, each macroblock (MB) in H.264 has a fixed size of 16x16. Pixels, while H.265 encoding units can be selected from 8x8 to 64x64.
Repeated quality comparison tests have shown that, at the same image quality, compared to H.264, the video stream size encoded by H.265 is reduced by about 39-44% compared to H.264. Due to different quality control methods, this data will change accordingly. The data obtained through subjective visual tests show that with a bit rate reduction of 51-74%, the quality of H.265 encoded video can still be similar to or better than H.264 encoded video, which is essentially better than expected The signal-to-noise ratio (PSNR) is better. The criteria for these subjective visual tests cover many disciplines, including psychology and human visual characteristics. Video samples are very extensive. Although they cannot be used as final conclusions, they are also very encouraging results.
The current HEVC standard has three modes: Main, Main10 and Main Still Picture. Main mode supports 8-bit color depth (that is, red, green, and blue colors each have 256 chromaticities, for a total of 16.7 million colors). Main10 mode supports 10-bit color depth and will be used on ultra high-definition television (UHDTV). The former two limit the chroma sampling format to 4: 2: 0. It is expected that the standard will be extended in 2014, and it will support 4: 2: 2 and 4: 4: 4 sampling formats (that is, it provides 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. In addition, the H.264 part (Hi444PP) can also support 4: 4: 4 chroma sampling and 14 deeper than characteristic. In this case, the difference between H.265 and H.264 is that the former can use less bandwidth to provide the same function, and the price is 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 released a Brahma BCM 7445 chip at a CES show in early January this year. It is a quad-core processor with a 28-nanometer process. , Can transcode four 1080P video data streams or H.265 encoded ultra-high-definition video with a resolution of 4096 × 2160 at the same time.
The birth of the H.265 standard is to transmit higher quality network video under limited bandwidth. For most professionals, the H.265 coding standard is no stranger. It is a video coding standard developed by ITU-TVCEG after H.264. The H.265 standard is mainly based on the existing video coding standard H.264. In addition to retaining some of the original technologies, it adds relationships that can improve the code stream, encoding quality, delay, and algorithm complexity. Related technologies. The main contents of H.265 research include improving compression efficiency, improving robustness and error recovery capability, reducing real-time delay, reducing channel acquisition time and random access delay, and reducing complexity.
Plastic Injection Insert Molding
1. The combination of the easiness of molding and bending of resin and the rigidity, strength and heat resistance of metal can make complex and sophisticated metal-plastic integrated products sturdily.
2. In particular, the combination of the insulation of resin and the electrical properties of metal can meet the basic functions of electrical products.
3. The pre-forming combination of multiple inserts makes the post-engineering of product unit combination more reasonable.
4. Insert products are not limited to metal, but also cloth, paper, wire, plastic, glass, wood, wire ring, electrical parts and so on.
5. For rigid parts and flexible parts on rubber sealing pad, the complex operation of arranging sealing ring can be eliminated after the integrated products are made by injection molding on the matrix, which makes the automatic combination of the following process easier.
6. Because it is the fusion of molten material and metal insert, compared with the pressing molding method, the metal insert gap can be designed to be narrower, and the reliability of composite product molding is higher.
7. Suitable resin and molding conditions may be used for sealing and fixation of susceptible products such as glass, coils, electrical parts, etc.
8. Inserts can also be completely sealed into the resin by selecting the appropriate mold construction.
9. After the insert is molded, it can also be made into a product with hollow grooves along with the core hole.
10. The combination of vertical injection molding machine and manipulator, the whole row device of insert products, etc., the insert forming engineering can be mostly automated production.
Plastic Injection Insert Molding,Washing Machine Plastic Injection Moulds,Plastic Injection Molding,Plastic Injection Molding Machine
Suzhou Dongye Precision Molding Co.,Ltd. , https://www.dongyeinjectionmolding.com