计算机应用 ›› 2013, Vol. 33 ›› Issue (03): 680-683.DOI: 10.3724/SP.J.1087.2013.00680

• 多媒体处理技术 • 上一篇    下一篇

X264的平均比特率控制算法优化

田一姝1,2*,沈强1,刘延伟1,张宇1,赵志军1   

  1. 1.中国科学院声学研究所 高性能网络实验室,北京 100190;
    2.无锡中科智能信息处理研发中心有限公司,江苏 无锡 214135
  • 收稿日期:2012-09-04 修回日期:2012-10-22 出版日期:2013-03-01 发布日期:2013-03-01
  • 通讯作者: 田一姝
  • 作者简介:田一姝(1987-),女,湖南娄底人,硕士研究生,主要研究方向:无线宽带、多媒体通信、物联网; 沈强(1981-),男,四川乐山人,博士,主要研究方向:物联网、数据挖掘; 刘延伟(1976-),男,黑龙江克山人,助理研究员,博士,主要研究方向:视频编码、通信; 张宇(1971-),男,河北唐山人,副研究员,博士,主要研究方向:计算机网络、物联网; 赵志军(1972-),男,河北唐山人,副研究员,博士,主要研究方向:物联网、移动通信网、互联网。

Average bit-rate algorithm optimization for rate control of X264

TIAN Yishu1,2*, SHEN Qiang1, LIU Yanwei1, ZHANG Yu1, ZHAO Zhijun1   

  1. 1.High Performance Network Laboratory, Institute of Acoustics, China Academy of Sciences, Beijing 100190, China;
    2.Wuxi Zhongke Research and Development Center of Intelligent Information Processing Technologies, Wuxi Jiangsu 214135, China
  • Received:2012-09-04 Revised:2012-10-22 Online:2013-03-01 Published:2013-03-01

摘要: 无线视频传输系统中,网络带宽往往是有限和动态变化的,这将导致视频信息在传输过程中的质量差以及不稳定,此时需要在视频编解码中采用码率控制进行调控。针对X264平均比特率(ABR)算法的不足,提出了两种改进措施:其一,根据实际输出比特和目标比特之差在帧层增加补偿算法来调整当前帧的量化参数(QP); 其二,改善缓存区增长函数以限制缓存区的过快增长。改进算法通过对同一视频序列不同目标码率以及不同视频序列同一目标码率两种方式进行实验仿真验证。仿真结果表明,在峰值信噪比(PSNR)平均值基本不变的情况下,输出的实际码率更加接近于目标码率。

关键词: X264, 视频编码, 码率控制, 平均比特率, 量化参数

Abstract: In wireless video transmission system, the network bandwidth is often limited and changing, which leads to poor quality and instability of the video information in this process. Therefore, a rate control regulation was needed in the video codec. In order to make up for the deficiency of Average Bit-Rate (ABR) algorithm in X264, two methods were proposed in this article. According to the gap between actual output bits and target ones, one is a new compensation algorithm in the frame layer to adjust the Quantization Parameters (QP) of the current frame and the other is to rewrite the growth function of the buffer to control its excessive growth. These two methods have been evaluated with different target bits but the same video sequence, and with different video sequences but the same target bits, respectively. The results show that actual output bit rate is closer to the target one on condition that the average Peak Signal-to-Noise Ratio (PSNR) stays the same.

Key words: X264, video coding, rate control, Average Bit-Rate (ABR), Quantization Parameter (QP)

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