What are the main existing encoding and decoding technologies? What are its technical principles and core technologies?
　　
The commonly used encoding and decoding technologies currently include MPEG-4, H.264/AVC, HEVC (H.265), SVAC, Smart 265, etc. Especially in the field of video surveillance, MPEG-4 and H.264/AVC occupy the main market. In 2015, H.265 encoding and decoding products began to be promoted and gradually increased market demand, with a trend towards replacing H.264.
　　
Regardless of the encoding and decoding technology, its core is mainly to reduce transmission bandwidth as much as possible while ensuring video quality. Due to the correlation of video data, there is a large amount of redundancy in the video data stream (for example, the content expressed at different times is consistent). In order to eliminate these redundancies and express correlation with a small amount of information, there are generally intra frame data compression technology, inter frame data compression technology, and entropy coding compression technology.
　　
Adopting inter frame compression technology, mainly to remove redundant temporal information, generally consisting of motion compensation, motion representation, and motion estimation; The use of inter frame encoding and entropy encoding techniques can remove spatial redundant information, which generally consists of variable encoding, quantization encoding, entropy encoding, etc;
　　
　　What is the current status of existing encoding and decoding technologies? What is the current status of its application?
　　
At present, the video surveillance field mainly adopts MPEG-4 and H.264/AVC encoding and decoding technologies. In this field, users are most concerned about the clarity of videos and high storage costs. Compared with HPEG-4, H.264 has lower compression efficiency and better support for high resolution. Therefore, there are more products using H.264. However, considering compatibility issues, backend devices generally maintain the simultaneous application of both technologies.
　　
So with the comprehensive advancement of high-definition video surveillance and the demand for 4K and 8K high resolution, H.264 is somewhat inadequate. H. The superior algorithm, higher compression rate, and lower latency of H.265 have provided the necessary conditions for its development in the field of video surveillance, making it an inevitable trend. However, the more stringent charging standards of H.265 have made more manufacturers pale in fear.
　　
　What are the implementation methods of various encoding and decoding technologies?
　　
H. 264 mainly includes modules such as intra prediction, inter prediction, transform, quantization, deblocking filter, entropy coding, etc. The intra frame data compression adopts 16 * 16 block and 4 * 4 block intra frame prediction. The motion estimation required for inter frame data compression adopts high-precision 1/2 pixel difference prediction, 1/4 pixel difference prediction, and 1/8 pixel difference prediction techniques;
　　
H. 264 adopts a motion vector prediction value and uses Columbus index encoding for motion vector difference encoding. The characteristic of this encoding method is that the smaller the value, the fewer bits are used. Therefore, as the amplitude of motion vectors increases significantly, the compression rate of the methods used for predicting and encoding motion vectors in H.264 will gradually decrease,
　　
H. The 265 standard was developed based on the H.264 standard, retaining its original technological advantages while improving some related technologies, so its implementation is basically consistent with H.264. The new technology is mainly used to improve the relationship between bitrate, encoding quality, latency, and algorithm complexity, achieving * setting.
　　
　What are the differences in implementation methods among various encoding and decoding technologies?
　　
In the previous question, we mentioned that the implementation of H.265 and H.264 remains consistent, with only some technical differences. For example, in terms of intra frame prediction, H.264 only supports prediction in 8 directions, while H.265 supports prediction in 33 directions; H.264 only supports 16 * 16 macro block processing in the encoding unit, while H.265 supports the selection of 8 * 8 to 64 * 64 macro blocks; H. 265 also has clear definitions in the encoding and decoding standards for 4K and 8K; H. The encoding optimization of 265 saves more bandwidth for transmission and storage, and in the same video effect, it saves 50% of bandwidth.
　　
　　What are the encoding and decoding technologies used by your company? What are the main applications of products in which fields?
　　
The encoding and decoding technologies currently used by Red Apple mainly focus on MPEG-4, H.264, and H.265. Mainly used in high-definition network digital matrices, high-definition decoders, intelligent video display and control systems, streaming media servers, network keyboards and other related products, especially in 2016 when high-definition H.265 products will be fully launched.
　　
　　What are the technical difficulties encountered by your company in using encoding and decoding technology? How did you respond?
　　
Compatibility, as a backend device manufacturer, requires sufficient compatibility capability in the product;
　　
Bandwidth requirements. In actual project applications, some customers have not fully considered the bandwidth pressure on the backend and have not provided sufficient transmission bandwidth in the switching nodes, resulting in instability in the decoding of backend products and greatly affecting video fluency, real-time performance, etc;
　　
The diversity of transmission and the definition of encoding and decoding technology often extend to the encoding of data, without control over transmission. Often, some manufacturers add some custom content during the packaging process.
　　
What do you think are the advantages and disadvantages of various encoding and decoding technologies such as MPEG-X, H.26X series, SVAC series, Smart 265, etc? H. The technical advantages of 265 are mainly manifested in:
　　
Lower transmission bandwidth;
　　
Larger and more flexible macro block processing and transformation blocks;
　　
Use a new motion vector prediction method. Different from H.264's spatial domain based motion vector prediction method, H.265 expands more directions for intra frame prediction, and expands the set of prediction blocks from the original spatial domain to the time domain and space-time mixed domain. The selected prediction blocks are calculated based on the rate distortion criterion;
　　
More consideration is given to parallel design, H.265 introduces parallel computing ideas such as Entropyslice and WPP, and uses encoding algorithms with higher parallelism;
　　
The improvement of robustness enhances the reliability of the product;
　　
Higher resolution definition, video images support 4K and 8K resolutions;
　　
Higher video frame rates, with video frame rates ranging from 30 fps to 60 fps, and even ultra-high frame rates of 120 fps or even 240 fps;
　　
　　What obstacles have various encoding and decoding technologies encountered in the promotion process? How should we respond?
　　
H. 265 and MPEG-4 have been widely promoted and applied. Let's mainly talk about the promotion of H.265. Firstly, only a few manufacturers such as HiSilicon have released chips for H.265 encoding and decoding;
　　
Secondly, with the development of the industry, H.265 has gradually been supported in the fields of video surveillance and television. However, in order to promote it comprehensively, important areas such as movies, media, mobile terminals, media players, games, projectors, and data storage are needed;
　　
After Zui, the strict charging standards of H.265, compared to the low charging standards of H.264 (in fact, MPEGLA has already relaxed the authorization of H.264), the charging standards of H.265 are the primary factor for promotion. In the field of video surveillance, the low bandwidth advantage and small market volume of H.265 can be quickly promoted, but in other fields, the high fees have to be carefully considered by manufacturers.
　　
　　What is the development trend of encoding and decoding technology? What do you think?
　　
At present, the development of H.265 in the security field is unstoppable. Some security companies have already launched H.265 products, but the promotion of H.265 in conjunction with storage and backend decoding is not particularly widespread. It is expected that by 2016, most security companies will launch H.265 products across the board.
　　

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