H.264 code rate control method

Abstract

The invention discloses an H.264 code rate control method which belongs to the technical field of video coding. The prior method is realized in a way that: the weighted sum of the mean difference of image gray histograms and the mean absolute error rate of image brightness components is used as a frame complexity factor, and the target bit number of the current coded frame is determined according to the complexity factor. On the basis of the prior method, the method of the invention considers the effects of the characteristics of the coded frames on the control on the code rate of the current frame, introduces an adjustment factor, and dynamically adjusts quantization parameters and optimizes the rate distortion by using the adjustment factor. The method can accurately control the code rate and obtain better image quality at the same time. The method also well inhibits the interframe quality fluctuations, thereby enhancing the smoothness of video images and keeping a lower occupancy rate of an encoder buffer area.

Description

technical field [0001] The invention relates to the technical field of video coding, in particular to a code rate control method for H.264 video coding. Background technique [0002] In video communication, the compressed and coded information flow often needs to be transmitted on the network with unbalanced bandwidth. In order to make the coded video stream well adapt to the bandwidth, especially adapt to the low-bandwidth channel or time-varying wireless channel and make full use of the limited network resources, bit rate control has become an essential link in the video communication system. The main task of bit rate control is to collect information such as buffer status and image activity to allocate a certain number of bits to each image, so that the output bit rate can be controlled at a given standard and the image distortion is minimized. [0003] In the rate control method of H.264 / AVC, due to the use of quantization parameters in the rate control and rate-distort...

AI Technical Summary

Problems solved by technology

However, this method is only optimized from the perspective of frame-level target bit allocation, and the traditional method in JVT-G012 is still used when calculating the quantization parameters, without considering the influence of the characteristics of the encoded frame on the rate control of the current frame

In this method, the inaccuracy of the linear MAD prediction model and the header information bits may cause the quantization parameters calculated by the binomial model to fail to produce the expected coded bits

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