In the proposed mbaff scheme , the top field of the current picture is used as a reference . the experiments are implemented on the platforms of audio video coding standard base profile and h . 264 avc , respectively 然而在h . 264 avc的mbaff算法中，当采用帧编码模式时，在对宏块对的底场进行编码时，没有使用当前帧的顶场作为参考。
It computes the distance between different macorblocks utilizing ehd and scc as similarity . if the distance is below a preset threshold , they are considered as similar , and are combined into a collection 用ehd和scc作为相似度准则计算各个宏块之间的距离,如果它们之间的距离小于一个给定的阈值,则认为它们的纹理特性相似,就把这两个宏块合并到同一集合中。
6 b slice : a slice that may be decoded using intra prediction from decoded samples within the same slice or inter prediction from previously - decoded reference pictures , using at most two motion vectors and reference indices to predict the sample values of each block 任意片顺序：在片的解码顺序中，图象中的一些片的首宏块的地址可能比同一副图象中的前面的片的首宏块的地址小。
In order to solve them , a new motion estimation algorithm based on macroblock partition is proposed in this paper , and a new rate control policy is adopted . simulations show that the proposed algorithms can improve system coding efficiency and image quality 为了有效地对块效应进行消除，本文提出了一种新的宏块预测分区运动估值算法并采用了一种新的码率控制策略，实验结果表明改进算法在图像质量上优于原算法。
So the video segmentation research in this paper is based on mpeg video . shot detection is the most fundamental operation and very important step in cbvar . shot detection is a technique that divides video data into physical units , generally called shots 在解压域的镜头检测中,提出一种基于视觉特征的突变镜头检测方法;在压缩域的镜头检测中,本文采用了基于宏块类型信息的镜头检测方法,可以有效的检测出突变和部分渐变镜头。
Considering the stability and continuity of face region , and the error propagation effect due to the high error rate in wireless channels , the intra - refresh method is used . the redundant data is not too much owing to the continuity , and the error propagation effect can be stopped accordingly 由于视频中出现的人脸具有稳定性,连续性等特点,同时考虑到无线移动信道由于误码率高而引起差错传播问题,所以采用帧内编码宏块刷新的方法。
According to the complexity threshold , we auto - adaptatively adjust the qp . we use the smaller qp to quantify the more complicated macroblock and use the bigger qp to quantify the less complicated macroblok . the proposed algorithm can improve the h . 264 standard algorithm by a rate control algorithm on macroblock layer 在宏块层利用了现有mad值表示宏块复杂度,进一步根据宏块的复杂度阈值自适应地调整量化参数qp ,对复杂度高的宏块采用较小的qp值,进行精细量化;对复杂度低的qp值采用较大的qp值,以节约比特数。
In packet based wireless video communications , when best band distribution , not only source distortion should be considered , but also channel distortion caused by channel errors . the existing macroblock - layer rate control schemes calculates quantization parameters of all macroblocks ( mb ) in a frame in a raster scan order , and then encodes the mbs in the same order . actually , the quantization distortion is heavily dependent upon the coding order of mbs 在基于包的无线视频传输中，最佳带宽分配时，不仅要考虑信源编码失真，也要考虑由于信道差错引起的信道失真；已有的宏块层码率控制算法以矩阵扫描的顺序计算一帧中所有宏块的量化参数，事实上量化失真与宏块的编码顺序有很大关系，改变宏块的编码顺序，使复杂的宏块分配到更多的比特数，显然能大大提高编码效率。
Firstly , we directly use the motion vectors of macro - blocks defined in mpeg - i / ii compressing standards and filter the immobile macro - blocks . then , we build a skin color model in ycbcr color space using the convergent property of skin color , and we present the gaussian model skin recognition method and positive - negative look - up table method in details . and we analyze the texture of skin after wavelet transform and present a bayesian method based texture recognition method and a high texture filtering method 根据皮肤的运动性，首先直接利用mpeg -中的压缩标准中有关宏块运动预测的方法，提取宏块的运动矢量，将没有运动的宏块过滤掉；然后，利用皮肤颜色的聚合性，在ycbcr颜色空间建立了皮肤的颜色模型，并分别阐述了基于高斯分布模型的皮肤检测法和正反概率表方法；最后，通过对皮肤进行小波变换后的纹理进行统计后，发现有效的利用皮肤纹理特征，可以比较有效的过滤掉那些具有类似于皮肤颜色的背景，分别阐述了基于贝叶斯方法的纹理检测方法和高纹理过滤法。
