Code rate control method of video coding and system thereof

Abstract

The invention relates to code rate control and discloses a code rate control method of video coding and a system thereof. According to code stream output information, a channel bandwidth is predicted and an encoding rate is correspondingly adjusted so that output delay can be well controlled under a condition that the channel bandwidth is limited and is easy to change and a low delay application scene demand is satisfied. The method comprises the following steps that the current channel bandwidth is predicted; according to a current channel bandwidth prediction value, a target code rate is distributed; according to the distributed target code rate, a code stream size of a previous coded frame and a coding image complexity, a corresponding quantification parameter is calculated and obtained; according to the quantification parameter, coding processing is performed on an image to be coded, an encoding stream is output, and the code stream size of the current coded frame and the coding image complexity are output; a code stream output buffer area carries out output time delay control according to the current channel bandwidth prediction value and code stream residence information of the code stream output buffer area.

Description

technical field [0001] The invention relates to code rate control, in particular to a code rate control method and system for video coding. Background technique [0002] The invention relates to code rate control, in particular to a code rate control method and system for video coding. At present, the demand for network cameras for security monitoring is increasing day by day. Network cameras are a new generation of products combining traditional cameras and network technology. The main technologies involved include image processing technology, video coding technology and network technology. One of the main disadvantages of network cameras compared to traditional analog cameras is the greater system latency. [0003] Bit rate control is one of the core technologies of video coding and also one of the main means of delay control. Existing bit rate control methods, for example, MPEG-2 standard test model 5 ("TestModel5", referred to as "TM5"), H.263 standard test model 8 ("T...

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Problems solved by technology

[0004] 1. I-frame quantization parameters simply use pre-determined values, without considering the relevance of the scene, the code rate is poorly controllable, and the output delay is uncontrollable in a bandwidth-limited environment

[0005] 2. The code rate control system has poor adaptability to channel bandwidth changes. In application scenarios where channel bandwidth is limited and variable, the output delay of encoding cannot be guaranteed

[0006] 3. The correlation between code stream output buffer and code rate control is weak. The code rate control method does not make full use of the code stream buffer and channel bandwidth information to control the output delay, and is slow to respond to changes in the environment.

[0007] 4. The frame rate conversion is not considered to be included in the bit rate control system, and the overflow frame loss strategy is simply adopted, so the effect of the frame rate conversion is poor

The existing code rate control method is established based on an ideal channel model, and the effect is acceptable when the channel bandwidth is sufficient, but the effect is poor in the environment where the bandwidth is limited and variable, especially the output delay cannot be guaranteed and cannot meet the requirements. Requirements for low-latency application scenarios

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