1、关于 FMO分离模式下 H.264/AVC 视频传输误差控制的研究 摘要： H.264/AVC 视频压缩标准对信道错误的鲁棒性是重点由它错误控制技术进行评估的，我们称错误评估技术为 FMO。我们调查研究了 FMO 作为一种 H.264的误差控制技术是如何在一个容易产生错误的网络中对于传输误差和包丢失进行最好的处理。一种新的使用 MBAmap 将宏块映射到条带组的方法已经采用，这种方法可以帮助在解码中进行误差隐蔽技术并且提高了被接收视频的主客观性能。 下载 关键词： FMO H.264/AVC 误差控制 MBAmap 视频传输 Abstract： The robustness of the H.
2、264/AVC video compression standard against channel error is evaluated with the focus on one of its error resilience tools called of H.264 can be deployed best for coping with the transmission errors and packet losses in an error-prone netws using MBAmap has been introduced which helps error concealm
3、ent at decoder and improves subjective and objective quality of the received viideo transmission 1.Introduction The syntax of H.264/AVC video coding on average reduces 50% bit rate as compared to previous standards keeping similar level of encoder optimizateo transmisss a few error resilience featur
4、es to protect bitstream from possible errors and packet loshich FMO relies on how effectively the adjacent macroblocks of a video frame scattered between different slicegroMBAmap (Macroblock Allocation Map) consisting of an identification number for each MB in the picture specifying the slMO to disp
5、erse all possible errors for a better quality of received vist important tools introduced in H.264 which can be used to scatter possible errors throughout the frdifferent slice groups with different patterame and a scan order in a slerent slicegron (MBAmap) by using the following equats the address
6、of macroblock located in particular column (a) & row (b) and n as the number of slicegroprocedure is followed to assign slicegroups to each of macroblock in the frcoordering where no any macroblock is surrounded by the other MB from the same slicegrhas been shown in utions and does not change until
7、different number of slicegroups is ud to disperse errors throughout the frame in case more than one particular slicegroups are l 5)， (2， 6) and (3， 7) occurring in coluaccumulated in columnar area of limited regions as shown for the pair (1， 5) in a possibility to use maximum two available MBs for c
8、oncealment which are adjacent neighbors to a lost MB lying in the horizontal direct to the lost pair is also l type of pattern to get maximum level of randomization in MBAmap keeping number of MBs in each SG eqills the requirements of a robust MBAred pattern of FMO by introducing an MBA-map that arr
9、anges MBs into SGs without repeating a particular orcegroups in the neighborhood of each MB. Let?s suppose we have total 6 slicegroups， all possible combinations of neighboring slicegroups for each MB can be calculated as， ?nCr where n=6-1 &r=4(direct neighbors top， left， right， bottom)?nCr= ?5C4= 5
10、!/(5-4)!4! = 5 There are total 5 possible combinations of neighboring pairs that can be introduced around a SG. For example， slice group 0 can have neighbors as any of following 5 combinati5) (2， 3， 4， 5) We introduce all of these neighboring pairs in the neighborhood of SG 0 at different locations
11、in the MBAmap (grey blocks in l follow the same crite repeat a particular pattern and all the SGs almost have same number of macrobloch other， to spread possible errors when this particular SG is latterns for error resilient video transmissjective and subjective quality， we use the sequence foreman
12、in a simulated error -prone netwof 30 quantization parameter (Q=28). Experiments have been conducted for different number of slicegrorn， we consider Gilbert model with 50% probability that a packet gets lost if the previous packet was l conventional pattern in getting objective qualuality with a uni
13、form distribution of errors， which is the main purpose of using FMO as error resilient tool in H.264/oss of slicegroups among repetitive pairs， the error is limited in columnar areas when H.264 pattern is used but is scattered well in case proposed pattern in MBAmap is emploparticular regions and th
14、e process of concealment finds more error-free MB. It produces less distortion in the recovered block and results in more improved subjective qualspersed pattern for FMO in H.264/AVC that performs the distribution of MBs into slicegroups in an optimal at fully provides isolation of a lost macroblocks decreasing their resultant distortMBAmap for error resilient transmission of video contepattern can?t avoid error accumulation in limited areas in case more than one slicegroups are lost and the results show the effectiveness of proposed pattern over it. (责任编辑：何秀秀 )
