期刊名称：International Journal of Advanced Computer Science and Applications(IJACSA)
印刷版ISSN：2158-107X
电子版ISSN：2156-5570
出版年度：2019
卷号：10
期号：12
页码：177-185
出版社：Science and Information Society (SAI)
摘要：The Advanced Video Coding (H.264/AVC) has
proved its ability in finding the tradeoff between the compressed
bit rate value and the visual quality of video comparing to the
others of traditional coding. One of the most encoder stages
consuming time is the intra prediction in which different sizes of
a block are exhaustively examined for selecting the suitable block
size to the best block mode decision. In this paper, an efficient
approach is suggested to select the best block size for the intra
prediction adaptively to achieve high compression efficiency. The
proposed approach exploits the idea of quad tree decomposition
for blocks partitioning based on a predefined threshold value. An
optimal global threshold value based on two dimension Otsu
technique is suggested for the decision of block division in this
work. The proposed technique is carried out on different set of
videos resolutions with different quantization parameters using
Matlab software. The comparison of the proposed approach with
the reference JM18.6 video coding is done in terms of bit rate
(BR), time saving and peak signal to noise ratio (PSNR). A
tangible acceleration on the running time can be accomplished
besides improvement in both of visual quality and bit rate with
some of QCIF and CIF videos resolution by the proposed
technique. The simulation results demonstrate saving in time by
average 42% to 68% with CIF and QCIF videos. Concerning the
visual quality in terms of Bjontegaard Delta parameters, the
PSNR improved in which its value increased from 0.2 to 1.6,
while the value of BR reduced from 0.79 to 15.3 respectively with
some videos of resolutions QCIF, CIF and 720p. In addition, the
performance of the suggested approach with the high resolution
videos achieves minor improvement with some of them while has
a slightly degradation with others of them.
关键词：H;264;AVC coding; intra prediction; block size
decision; Otsu two dimensions method
