H.265 is a new video coding standard developed by ITU-T VCEG following H.264. H.265 standard around the existing video coding standard H.264, retain some of the original technology, while some of the relevant technology to be improved. The new technology uses advanced technology to improve the relationship between codestream, coding quality, latency and algorithm complexity to achieve optimal setup. The research contents include improving the compression efficiency, improving the robustness and error recovery ability, reducing the real-time delay, reducing the channel acquisition time and random access delay, reducing the complexity and so on. H264 can be achieved by using 1 ~ 2Mbps transmission speed 720P (resolution 1280 * 720) ordinary high-definition audio and video transmission.
H.265 is designed to transmit higher quality network video at a limited bandwidth, allowing only half the bandwidth to play the same quality video. It also means that our smartphones, tablet machines and other mobile devices will be able to play 1080p full HD video online. H.265 standard also supports 4K (4096 × 2160) and 8K (8192 × 4320) ultra-high-definition video. It can be said, H.265 standard to keep up with the network video display "high resolution" of the footsteps.
H.264, also the tenth part of MPEG-4, is a joint video group (JVT, Joint Video Team) composed of 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 explicitly illustrates its two aspects of the developer.
H.264 biggest advantage is a high data compression ratio, in the same image quality conditions, H.264 compression ratio is MPEG-2 more than 2 times, MPEG-4 1.5 to 2 times. For example, if the original file size is 88GB, using MPEG-2 compression standard compression becomes 3.5GB, compression ratio of 25: 1, and the use of H.264 compression standard compression into 879MB, from 88GB to 879MB, H.264 compression ratio reached a staggering 102: 1. Low Bit Rate plays an important role in the high compression ratio of H.264. Compared with MPEG-2 and MPEG-4 ASP compression technologies, H.264 compression technology will greatly save the user's download time And data traffic charges. It is particularly worth mentioning that, H.264 has a high compression ratio while also has a high quality and smooth image, because of this, after H.264 compressed video data, the network transmission process requires less bandwidth, And more economical.
What is the difference between H.265 and H.264?
Before discussing what enhancements and benefits of H.265, let's take a look at H.264. H.264, also known as MPEG-4 AVC (Advanced Video Codec), is a video compression standard and is a widely used recording, compression and publishing format for high-precision video. H.264 is famous for its codec standard for Blu-ray Disc, and all Blu-ray players must be able to decode H.264. More importantly, because Apple had decided to abandon the Adobe VP6 encoding, select the H.264, the standard also with hundreds of millions of iPad and iPhone into the tens of thousands of households, has become the field of video coding Absolute overlord, occupies more than 80% of the share. H.264 is also widely used in network streaming media data, a variety of high-definition television broadcasting and satellite television broadcasting and other fields. H.264 has some new features compared to the previous coding standards, such as multi-reference frame motion compensation, block size motion compensation, intra prediction coding, etc. By using these new features, H.264 has more High video quality and lower bit rate, and therefore by the people's recognition, and is widely used.
The coding architecture of H.265 / HEVC is similar to that of H.264 / AVC, and also includes intra prediction, inter prediction, transform, quantization, Deblocking filter, entropy coding, and so on. However, in the HEVC coding architecture, the whole is divided into three basic units: coding unit (CU), forecast unit (PU) and transform unit (TU).
The current HEVC standard has three modes: Main, Main 10 and Main Still Picture. Main mode supports 8bit color depth (that is, red, green and blue colors each have 256 colors, a total of 16.7 million colors), Main 10 mode support 10bit color depth, will be used for ultra-high-definition television (UHDTV). The first two limit the chroma sampling format to 4: 2: 0. It is expected to expand the standard in 2014 and will support 4: 2: 2 and 4: 4: 4 sampling formats (ie, providing higher color reproduction) and multi-view encoding (such as 3D stereo video encoding).
In fact, H.265 and H.264 standards in a variety of functions have some overlap. For example, the Hi10P part of the H.264 standard supports 10bit color depth video. The other, H.264 part (Hi444PP) can also support 4: 4: 4 chroma sampling and 14-bit color depth. In this case, the difference between H.265 and H.264 is that the former can use less bandwidth to provide the same functionality at the cost of device computing power: H.265 encoded video requires more computing power To decode. There are already support for H.265 decoder chip released - the United States Broadcom (Broadcom) in early January this year, the CES exhibition released a Brahma BCM7445 chip, which is a 28-nanometer process using quad-core processor, Can be transcoded at the same time four 1080P video data stream or resolution resolution of 4096 × 2160 H.265 encoding ultra-high-definition video.
The H.265 standard was created to deliver higher quality network video over limited bandwidth. For most professionals, the H.265 coding standard is no stranger, it is ITU-TVCEG following H.264 after the development of video coding standards. H.265 standard is mainly around the existing video coding standard H.264, retained some of the original technology, the increase can improve the stream, coding quality, delay and the complexity of the relationship between the algorithm, etc. Related technology. The main contents of H.265 research include improving compression efficiency, improving robustness and error recovery ability, reducing real-time delay, reducing channel acquisition time and random access delay, and reducing complexity.
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