Optimization method and system for code rate control of video monitor in 3G network

Abstract

The invention provides an optimization method and system for code rate control of a video monitor in a 3G network. The method comprises: taking a bandwidth value returned in the 3G network as a target code rate in an X246 code rate control algorithm; according to the ABR rate control algorithm in X264, obtaining quantification parameters; employing the following compensation algorithm to optimize the quantification parameters of the previous step: after the quantification parameter of each frame is obtained, according to already encoded frames, obtaining an actual output code rate by the time of a current frame, and according to the obtained actual output code rate, calculating the difference of the actual output code rate and the target code rate by the time of the current frame; judging the obtained difference, and if the difference is smaller than a first set value and the obtained quantification parameters are greater than the average quantification parameter of the already encoded frames, reducing quantification parameter values; and if the difference is greater than a second set value and the obtained quantification parameter values are smaller than the average quantification parameter of the already encoded frames, increasing the quantification parameter values; and encoding the current frame through the quantification parameters so as to finish encoding operation of the video monitor in the 3G network.

Description

technical field [0001] The present invention relates to the H.264 video encoding standard, mainly aimed at the current situation that the security video monitoring system is unstable due to the limited network bandwidth in the video transmission process, and specifically relates to an optimization method for the code rate control of a video monitor in a 3G network and system. Background technique [0002] H.264 is a video coding standard jointly developed by the International Telecommunication Unite (ITU) and the Motion Picture Experts Group (MPEG). It is the latest international video coding standard with good compression performance and Network affinity, very suitable for real-time video communication systems. Among them, the open source codes based on H.264 mainly include: the test software JM developed by the German HHI Institute, the codec X264 initiated by the Central Research Institute of the Central School of Paris in France and jointly developed by the Internet Fre...

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Problems solved by technology

[0007] 2. Quantization Parameter (Quantization Parameter, QP): QP reflects the compression of spatial details. If QP is small, most of the image details will be preserved; when QP increases, some image details will be lost, and the bit rate will also increase. decrease, but at the same time the image quality will decrease

The quantization parameter QP obtained according to the above method is not accurate to directly encode the current frame, and the output bit rate is allowed to have an error of ±10%.

[0033] 2. The complexity of each macroblock in the macroblock layer is not the same. After the ABR code rate algorithm obtains the quantization parameter QP at the frame layer, all macroblocks belonging to the frame are quantized with this unified QP value. Therefore, it There is no fine-grained macroblock layer rate control mechanism

[0034] 3. The limit of the buffer area is too broad and has no extreme value, and the growth of the buffer size is only related to the initial value of the buffer area, the current number of frames, and the encoding frame rate. The growth size is not precise, which is not conducive to bit rate control

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