H.264 code rate control method

Abstract

The invention discloses an H.264 code rate control method which comprises the following steps of: Step 1, calculating macro block MB motion complexity SAD and a visual perception weight of an image by executing pre-motion-estimation; Step 2, calculating an image frame-level target bit number by integrating an image target code rate, the target code rate and a filling degree of a bit stream buffer region; Step 3, carrying out frame-level code rate control on the image; Step 4, carrying out MB-level code rate control on the image and by a code rate control model, distributing a suitable quantization parameter QP for each MB according to the MB motion complexity and the frame-level target bit number which are obtained in the process; Step 5, carrying out formal motion estimation on the image. Compared with an existing method, the H.264 code rate control method has the advantages that operation complexity is obviously reduced; code rate control accuracy of encoding a decoded and reduced video again is improved; the treatment process of the H.264 code rate control method has the characteristic of low latency; the H.264 code rate control method has a more obvious effect on video communication with high requirements on real-time performance.

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 network resources provided and ensure that users obtain the best perceived quality, video communication systems need to apply rate control mechanisms. In video coding, rate control is a very open and extremely important technology. Different rate control strategies will not affect the interconnection of the system, but the quality of the control strategy directly affects the quality of the compressed video. And effective use of existing network bandwidth. So far, the published rate control algorithms adopted by international video coding standards mainly include MPEG2's TM5 model, H.263's TMN8 ...

AI Technical Summary

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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