A h.264 code rate control method

Abstract

The invention discloses a H.264 code rate control method, which includes the following steps: Step 1: Calculate the motion complexity SAD and visual perception weight of the image macroblock MB by performing pre-motion estimation; Step 2: Synthesize the image target code rate, the target frame rate and the filling degree of the code stream buffer to calculate the frame-level target bit number of the image; step 3: perform frame-level code rate control on the image; step 4: perform macroblocking on the image Level code rate control, its code rate control model according to the macroblock MB motion complexity and frame level target number of bits obtained in the above-mentioned process, distributes suitable quantization parameter QP for each macroblock MB; Step 5: carry out described image Formal Motion Estimation. Compared with the existing method, the present invention significantly reduces the computational complexity and improves the code rate control accuracy for re-encoding the decoded and restored video. The processing process of the present invention has the characteristics of low delay, and is suitable for video communication with relatively high real-time requirements. , the effect is more obvious.

Description

technical field [0001] The invention belongs to the technical field of video coding, and relates to a video coding control method, in particular to a low-delay H.264 code rate control method. technical background [0002] In multimedia communication, compressed video streams are transmitted on networks with inconsistent and changing bandwidth requirements. In order to make full use of the provided network resources and ensure users get the best sensory quality, the video communication system needs to apply a rate control mechanism. In video coding, bit rate control is a very open and extremely important technology. Different bit rate control strategies will not affect the interconnection of the system, but the quality of the control strategy will directly affect the quality of compressed video. and efficient use of existing network bandwidth. So far, the public rate control algorithms adopted by international video coding standards mainly include the TM5 model of MPEG2, the...

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Problems solved by technology

In this way, it creates a contradictory situation between the rate control algorithm and the rate-distortion optimization technology.

In order to obtain the picture activity complexity parameters required by the bit rate control process, the JVT-G012 method uses a linear prediction model to estimate the unknown complexity of the current frame from the known complexity of the previous frame, but executes for each macroblock (MB) Linear prediction involves extremely high computational load, especially unacceptable in high-definition video coding

Secondly, for decoding and restoring video in multi-point controllers such as video conferences, because the encoding process filters out high-frequency information, the difference between macroblocks between frames becomes smaller, and a large number of macroblocks are judged by the encoder as skip encoding mode. Excessively skip-encoded macroblocks impair the accuracy and stability of the linear predictor regression analysis, causing the predicted macroblock complexity to deviate significantly from the true value

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