公开(公告)号：US06826228B1

公开(公告)日：2004-11-30

申请号：US09700071

申请日：2001-01-26

申请人： Yau Wai Lucas Hui

发明人： Yau Wai Lucas Hui

IPC分类号： H04B166

CPC分类号： H04N19/198 ,  H04N19/126 ,  H04N19/132 ,  H04N19/137 ,  H04N19/14 ,  H04N19/146 ,  H04N19/152 ,  H04N19/159 ,  H04N19/17 ,  H04N19/172 ,  H04N19/176 ,  H04N19/179 ,  H04N19/196 ,  H04N19/61 ,  H04N19/87

摘要： This method and apparatus described herein imposes masking factors to the determined quantization step sizes of macroblocks of a video sequence such that encoding efficiency is increased. A conditional masking method can be used to take advantage of the fact that P-pictures are more important than B-pictures in terms of motion and scene updates as coding noise in such updates are likely propagated by P-pictures. The masking can be applied conditionally to motion/scene update regions of a picture such that coding noise is reduced and therefore bits are saved from less propagation of this noise. Before encoding each macroblock of a picture from an input video sequence, a video encoder with conditional masking determines if the macroblock type belongs to a significant motion or scene update region. A conditional masking factor is then determined for the macroblock based on the determined macroblock type and the picture coding type. The conditional masking factor is combined with a macroblock reference quantization step-size which may be calculated using conventional methods based on bit allocation and bit utilization, and an optional activity masking factor based on activity level of the macroblock and/or its surrounding region to form the final quantization step-size for coding of the macroblock.

摘要翻译： 这里描述的方法和装置对所确定的视频序列的宏块的量化步长施加掩蔽因子，使得编码效率增加。 可以使用条件屏蔽方法来利用P图像在运动和场景更新方面比B图像更重要的事实，因为这样的更新中的编码噪声可能由P图像传播。 掩蔽可以有条件地应用于图像的运动/场景更新区域，使得编码噪声减小，因此从该噪声的较少传播中节省了比特数。 在从输入视频序列对图像的每个宏块进行编码之前，具有条件掩码的视频编码器确定宏块类型是否属于有效运动或场景更新区域。 然后，基于所确定的宏块类型和图像编码类型，为宏块确定条件屏蔽因子。条件屏蔽因子与可以使用基于位分配和位利用的常规方法计算的宏块参考量化步长进行组合 ，以及基于宏块和/或其周围区域的活动级别的可选活动屏蔽因子，以形成用于宏块编码的最终量化步长。