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Method for controlling code rate in H263 coding

A control method and medium bit rate technology, applied in the field of encoding and decoding, can solve problems such as obvious block effect and ringing effect, and poor visual effect of images, so as to reduce block effect and ringing effect, increase actual frame rate, and reduce information lost effect

Inactive Publication Date: 2008-12-10
HUAWEI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0042] The present invention provides a code rate control method in H263 encoding to solve the problems of obvious block effect and ringing effect and poor image visual effect existing in the existing H263 encoding code rate control method

Method used

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  • Method for controlling code rate in H263 coding
  • Method for controlling code rate in H263 coding
  • Method for controlling code rate in H263 coding

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0065] Embodiment 1, GOB level control

[0066] The basic steps are the same as the prior art 1, the main difference is that more target bit rates are allocated for I frames, and less bits are allocated for P frames. According to the limited QP max Determines the quantization step size.

[0067] In the initialization step, the target number of bits for an I-frame, P-frame or B-frame image is assigned as follows:

[0068] a1: Determine the total number of bits B_all for each I-frame image cycle:

[0069] B_all=Interval*R / F

[0070] Wherein: Interval is the total number of frames of an I frame image interval cycle; R is the target code rate; F is the target frame rate;

[0071] a2: Determine the target bit number B_P or B_B of the P frame or B frame image:

[0072] B_P=B_B=B_all / (X+Interval-1)

[0073] Among them: X is the multiple of the setting

[0074] a3: Determine the target bit number B_I of the I frame image:

[0075] B_I=X*B_P

[0076] Frame skip processing:

[...

Embodiment 2

[0100] Embodiment 2, macroblock level control

[0101] The basic steps are the same as the prior art 2, the main difference is that more target bits are allocated for I frames, and less bits are allocated for P frames. According to the limited QP max Determines the quantization step size.

[0102] In the initialization step, the allocation of target bit numbers of I-frames, P-frames or B-frame images and the processing method of frame skipping are the same as those in the first embodiment.

[0103] Take the calculation of the quantization step size of the Kth macroblock as an example:

[0104] c1: calculate the initialization model parameter s1;

[0105] If the Kth macroblock is I(intra), set σ k 2 = σ k 2 / 3 . Let i=1 and j=0, B ~ 1 = B ...

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Abstract

The present invention relates to encoding and decoding technology, in particular to a code rate control method in H263 encoding, so as to solve the problems of obvious block effect and ringing effect and poor image visual effect existing in the existing H263 encoding rate control method. A method for controlling the code rate in H263 encoding, wherein the I frame, P frame or B frame image in the H263 encoding is quantized and encoded at the block group level or macro block level according to the divided block groups or macro blocks, and after completing each Frame skip processing is performed after the frame image is encoded; when the P frame or B frame image is quantized and encoded, the maximum value QPmax of the quantization step size of each block group or macroblock is limited to be less than or equal to 24. And during initialization, the target bit number of the I-frame image is X times the target bit number of the P-frame or B-frame image, and the X is greater than or equal to 3 and less than or equal to 14.

Description

technical field [0001] The invention relates to encoding and decoding technology, in particular to a code rate control method in H263 encoding. Background technique [0002] With the maturity of 3G technology, the supported functions are becoming more and more perfect. Multimedia service is a bright spot of 3G, among which video service is the most well-known. Currently commercial or trial commercial 3G networks provide video service. The 3G multimedia communication uses the H324M protocol, with a total bandwidth of 64Kbps. After removing the audio and H223 header overhead, the actual bandwidth obtained by the video is at most about 48Kbps. With such a low bandwidth, how to ensure the quality of the video becomes 3G The difficulties faced by terminals, video multimedia gateways, and H323 and SIP terminals interworking with them are also one of the most concerned focuses of users and operators. The H263 video codec protocol is one of the video protocols commonly used by 3G t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04N7/24H04N7/26
Inventor 张军乔志新果云亮罗裕辉靳彤
Owner HUAWEI TECH CO LTD