Method and device for controlling code rate in video coding

Abstract

The invention discloses a method and a device for controlling code rate in video coding, which is used in the code rate control process using a line macro block as the minimum arithmetic element. Aiming at the current line macro block, the method comprises the following steps: acquiring the initial code rate control parameter of the current frame; determining the QP value of the current line according to the initial code rate control parameter of the current frame, the coding result feedback information of the coded line macro block and a coding scene; and tickling the coding result information obtained after carrying out macro block coding on the current line according to the QP value of the current line. The invention can enhance the quality of the coded image as far as possible on the premise of accurately controlling the code rate.

Description

technical field [0001] The present invention relates to video coding technology in the communication field, in particular to a code rate control method and device in video coding. Background technique [0002] In the current video coding and compression technology, after the collected original video data is coded and compressed, the coded code stream has a higher compression ratio, but its code rate changes. In the field of video communication, the bandwidth of the communication channel is constant and limited, and the code stream whose code rate is constantly changing is not suitable for transmission in a constant channel. Therefore, rate control is introduced in video coding, such as figure 1 As shown, the purpose is to control the code rate of the code stream generated by the encoder within a certain fluctuation range. [0003] The basic principle of rate control is to control the occupancy of bits in the bit stream buffer by continuously adjusting the encoding quantiza...

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Problems solved by technology

[0007] figure 2 The rate control scheme shown, on the one hand, in some special scenarios, there will be a large deviation in the target bit rate allocation step; However, changes can easily lead to inaccurate control of the code rate and uneven distribution of the number of encoded bits; on the other hand, it is easy to cause uneven quantization and large differences in image quality;

[0008] image 3 The rate control scheme shown, because it uses two encodings, increases the computational complexity of rate control and is not suitable for applications in real-time systems

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