X265的平均码率控制算法优化

Average bit-rate algorithm optimization for rate control of X265

码率控制算法通过动态的调整编码参数,使产生的码率能在有限的带宽内稳定传输,并尽可能提高视频的质量。目前针对HEVC的并行编码以及对应码率控制已成为研究热点,现有并行结构下的平均比特率控制算法受到帧间依赖性的约束,待编码帧无法及时获得与其并行帧的实际编码比特数进行码率控制,因此本文算法利用比特数预测模型通过预测并行帧的实际比特数作为码率控制的参数,及时的进行并行编码并且在此基础提出了缓冲区的优化过程。仿真结果表明,相比原有算法,减少的平均码率误差约为4.43%,同时提高的平均PSNR约为0.21dB。

Rate control algorithm dynamically adjusts the encoding parameters to ensure stable transmission rate within the limited bandwidth,and maximize the quality of the video.The parallel encoding and rate control for HEVC has become advanced research focus.The average bit rate control algorithms under existing parallel structure is restrained by the inter-dependent,so the coding frame can＇t timely obtain the actual bits of frames which are in parallel with it.Therefore,in this paper,it uses the model which can predict frame＇s number of bits in parallel architecture to control bit-rate,and on this basis the optimization process is proposed of buffer.The results show that the method reduces the rate of error by 4.43%,and improves the average Peak Signal-to-Noise Ratio（PSNR）of 0.21 dB simultaneously.