Video coding and decoding Technology for audio and video Development

Video coding and decoding Technology for audio and video Development

In August 2012, Ericsson launched the first H.265 [1] codecs. In just six months, ITU (ITU) officially approved the adoption of the HEVC/H.265 standard, the standard is fully referred to as High Efficiency Video Coding, compared with the previous H. the 264 Standard has been greatly improved. Huawei, a Chinese company with the most core patents, is the leader of the standard. AnyChat solution, which has the leading audio and video development technology in China, currently uses H.264 video codec technology. It is believed that H.265 video codec technology will soon be followed.

The encoding architecture of H.265/HEVC is roughly the same as that of H. the 264/AVC architecture is similar to that of intra prediction, inter prediction, transform, and quantization) the deblocking filter and entropy coding modules are divided into three basic units in the HEVC coding architecture: encoding unit (CU), prediction unit (PU), and conversion unit (TU ).

Compared with H. 264/AVC, H.265/HEVC provides more tools to reduce the bit rate. For the encoding unit, H. in 264, the size of each Macro Block (macroblock/MB) is fixed 16x16 pixels, while the H.265 encoding unit can be from the minimum 8x8 to the maximum 64x64.

In addition, H.265 supports 33 types of intra-frame prediction modes (H.264 only supports 8 types), and provides better motion compensation processing and vector prediction methods.

On the tested surface of Dr. Bai Rui, video sizes encoded with H.265 will be reduced by about 39-264 in the same image quality compared to H.264. Due to the different quality control measurement methods, this data will also change accordingly.

The data obtained through subjective visual testing shows that H.265 video quality can be consistent with H when the bit rate is reduced by 51-74%. 264 encoded videos are similar or even better, essentially better than the expected SNR.

These subjective visual testing criteria cover many disciplines, including psychology and human visual characteristics. Video samples are very extensive, although they cannot be used as final conclusions, but this is also a very encouraging result.

Comparison between H.265 and H.265 video subjective visual testing, we can see that the bit rate of the latter is much lower than that of the former.

H.265 is a new video encoding standard developed by ITU-T VCEG following H.264. The H.265 standard revolves around the existing video encoding standard H.264, retaining some of the original technologies and improving some related technologies. The new technology uses advanced technologies to improve the relationship between code streams, encoding quality, latency, and algorithm complexity to achieve optimal settings. Specific research contents include: improving compression efficiency and error recovery capabilities, reducing real-time latency, reducing channel acquisition time and random access latency, and reducing complexity. Due to algorithm optimization, H264 can achieve SD digital image transmission at a speed lower than 1 Mbps; H265 can achieve 1 ~ 2 Mbps transmission speed: 720 P (resolution: 1280*720) normal HD Audio/Video Transmission.

H.265 is designed to transmit high-quality online videos with limited bandwidth. videos of the same quality can be played with only half of the original bandwidth. This also means that our smart phones, tablets and other mobile devices will be able to directly play P Full HD videos online. The H.265 standard also supports 4 K (4096x2160) and 8 K (8192x4320) ultra-HD videos. It can be said that the H.265 Standard keeps the network video behind the "High Resolution" of the display screen.

Within a few months, you may see devices that support H.265 decoding (such as smartphones and video cards) go public ). H.264 has ruled the past five years, and H.265 is likely to become the mainstream in the next five or even ten years. [2]