Low-delay code rate control method for 4K/8K ultra-high-definition video coding

Abstract

The invention discloses a low-delay code rate control method for 4K / 8K ultra-high-definition video coding. The method specifically comprises the following steps: (1) setting the length of a GOP as aninteger M, and setting the number of frames used for prediction in a conventional buffer area as K; (2) calculating the number N (i) of frames used for buffer area prediction when the ith frame in theGOP is coded; (3) calculating the estimated bit number of the i,..., i + N (i) th frame by using an Rq model; (4) calculating the saturation F (i) of the target buffer area of the ith frame, judgingwhether F (i) is smaller than 0.5 or not, if yes, letting q (i) be equal to q (i) * w or judging whether F (i) is larger than 0.8 or not, and if yes, letting q (i) be equal to q (i) / w, and executing the step (3) again; otherwise, selecting the current q (i) as the optimal quantization step length of the current frame, and executing the step (5); and (5) obtaining the optimal quantization step length to encode the frame. The method has the beneficial effects that the number of frames required by buffer area prediction is adaptively adjusted, so that the problem of increased coding delay causedby waiting for frames of other GOPs in buffer area prediction during GOP parallel coding is avoided.

Description

technical field [0001] The present invention relates to the technical field of video coding, in particular to a low-delay code rate control method for 4K / 8K ultra-high-definition video coding. Background technique [0002] With the rapid development of network communication and video processing technologies, technologies such as 4K, 8K and HDR (High Dynamic Range) have gradually become people's new requirements for visual experience. The data volume of 4K / 8K video is large, and the requirements for encoding and compression performance are relatively high. At present, the encoding and compression standards adopted for 4K / 8K video at home and abroad mainly include HEVC and AVS2. Their compression efficiency is high but the computational complexity is relatively large. However, 4K / 8K real-time live broadcast usually requires the speed of the encoder to reach more than 50 frames per second. Therefore, how to improve video output stability under certain network bandwidth and spe...

AI Technical Summary

Problems solved by technology

The data volume of 4K / 8K video is large, and the requirements for encoding and compression performance are relatively high. At present, the encoding and compression standards adopted for 4K / 8K video at home and abroad mainly include HEVC and AVS2. Their compression efficiency is high but the computational complexity is relatively large. And 4K / 8K real-time live broadcast usually requires the speed of the encoder to reach more than 50 frames per second

On the other hand, the end-to-end delay in real-time live broadcast is also very critical. The existing method sets the number of frames required for buffer prediction as a fixed value. If the frame of the first GOP needs to meet the number of frames required for buffer prediction Waiting for the frame input of the third GOP, the frame output delay of the first GOP will be greatly increased

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