基于宏块的渐进、精细可伸缩的视频编

渐进精细可伸缩(PFGS)的视频编码是面向Internet的视频流化应用中的一项重要技术,同MPEG-4标准中的精细可伸缩(FGS)的视频编码相比,PFGS视频编码具有更高的编码效率.然而,由于现有的PFGS方法以帧为单位来选择编码时的参考图像,因此该方法很难同时在编码效率和误差控制方面都取得好的效果.提出了一种灵活、高效的基于宏块的PFGS编码方法,并提出3种帧间(INTER)编码方式用于增强层宏块编码,其中的一个编码方式把原有的PFGS视频编码中的误差控制技术扩展到了宏块层.同时也提出了一个编码方式选择算法以确定每个增强层宏块的编码方式,由于该算法仅需用到时域预测信息,因此实现起来非常简单,并且性能稳定.实验结果表明,基于宏块的PFGS视频编码既能有效地消除低码率下的误差传递和累积,也能提高在其他码率下的编码效率.

Macroblock-Based Progressive Fine Granularity Scalable Video Coding

The progressive fine granularity scalable (PFGS) coding is a promising technique for streaming video applications due to its much higher coding efficiency than the FGS (Fine Granularity Scalable) coding in MPEG-4 standard. However, since the original PFGS scheme only chooses its reconstructed references as frame-based, it is very difficult to achieve a good trade-off between high coding efficiency and low drifting errors. In this paper, a flexible and effective scheme is presented to control the PFGS coding at macroblock level. Three INTER modes with distinct characteristics are first proposed for the enhancement macroblock coding. One coding mode among them provides a novel method to effectively reduce the drifing errors that may occur at low bit rates. Moreover, a decision-making mechanism based on temporal predictions is developed to choose the optimal coding mode for each enhancement macroblock, which offers a consistent improved performance for sequences with different contents and formats. Furthermore, the proposed control scheme can be easily implemented without any additional computations. The experimental results show that the macroblock-based enhancement layer coding technique technique using the three INTER modes and the proposed decision-making mechanism can effectively reduce the drifting errors at low bit rates, while providing high coding efficiency at moderate or high bit rates.