Method and device for selecting optimal intra-frame coding mode for video sequence

Abstract

The invention provides a method and a device for selecting an optimal intra-frame coding mode for a video sequence. The method comprises the steps of dividing an image into a plurality of code blocks; determining a plurality of intra-frame coding modes according to the sizes of the code blocks; calculating horizontal and perpendicular gradients and the like of pixels in the code blocks; calculating the slope of the coding direction that each intra-frame coding mode corresponds to, and dividing the intra-frame coding modes into N groups; comparing the slopes in all of the gradient directions with the first to the Nth scheduled intervals so as to obtain the first to the Nth gradient energy values; selecting a group of intra-frame coding modes that the maximum gradient energy value corresponds to as a candidate prediction mode set; calculating the rate distortion cost of each coding mode in the candidate prediction mode set, and selecting the intra-frame coding mode with the minimum rate distortion cost as the optimal intra-frame coding mode for the code blocks. The method has the advantages of reducing the amount of calculation of the rate distortion cost and increasing calculation speed, and is suitable for real-time coding.

Description

technical field [0001] The present invention relates to the technical field of video coding, in particular to a method and device for selecting an optimal intra-frame coding mode of a video sequence. Background technique [0002] With the continuous improvement of network technology and terminal processing capabilities, people put forward new requirements for MPEG-2, MPEG-4, H.264, etc., which are widely used at present. Hope to provide: 1. High definition, 2. Stereoscopic, 3. Mobile wireless, to meet new applications in new fields such as home theater, remote monitoring, digital broadcasting, mobile streaming media, portable camera, and medical imaging. In response to these new requirements, the HEVC coding standard came into being. [0003] Although the existing video coding standard HEVC has obvious advantages in coding efficiency, the high computational complexity introduced by them to improve compression efficiency is unbearable for practical applications, especially r...

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Problems solved by technology

[0005] However, the intra prediction mode decision is based on the macroblock rate-distortion optimization strategy. Although the accuracy of encoding and compression is high after too many mode selections, the complexity and encoding time are greatly increased, which is not conducive to its application in real-time systems.

For the entire real-time coding system, although intra-frame coding takes up a small proportion of the entire coding process, it has a long coding time, making direct intra-frame coding a big obstacle to the realization of real-time systems

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