摘要： 针对不同的视频内容造成编码前几帧质量低下的问题,提出一种基于I帧复杂度的初始量化参数(QP)选择算法。在编码前利用解码码流中得到的I帧宏块模式信息,运用宏块中的3种不同帧内预测模式判断I帧的复杂度,并采用目标码率和初始QP的关系重新拟合新的初始QP的选择方法。实验结果表明,在相同的码率下,该算法避免了传统码率控制中初始QP选择算法的弊端,可提高视频的客观质量,降低判断I帧的复杂度,客观峰值信噪比值比现有相关算法平均提高0.6 dB,最高提高1.69 dB。

关键词: 视频转码, 量化参数, 复杂度, 码率控制, H.264标准

Abstract: For different video content causes poor quality in the front few frames.This paper proposes an initid Quantization Parameter(QP) selection algorithm based on I frame complexity.The algorithm utilizes the three prediction modes of I frame and calculates the complexity of I frame.At the same time,combining with the target bit rate and the relationship between initial QP selects the best initial QP.Experimental results show that compared with other algorithms under the same bit rate,the algorithm avoids disadvantages of the traditional rate control of initial QP selection algorithm,it improves the quality of video and reduces the complexity of judgment I frame.The predicted initial QP is more accurate,and it greatly improves the performance of rate control.The average Peak Signal to Noise Ratio(PSNR) is improved by 0.6 dB and the maximum performance gain in PSNR is up to 1.69 dB.

Key words: video transcoding, Quantization Parameter(QP), complexity, code rate control, H.264 standard

中图分类号: 

• TP391