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针对H.264/AVC高档次标准中帧内模式选择计算复杂度高的问题,提出一种新颖的基于纹理信息的快速帧内模式选择方法。利用绝对误差均值检测宏块的复杂度,选择块尺寸模式;利用平均绝对相邻像素差来检测图像块的纹理方向,筛选候选预测模式。实验结果表明,上述两部分算法单独使用都能够有效降低帧内模式选择的计算复杂度,使编码速度分别提高27%和64%,并且对率失真性能的影响可以忽略不计。利用整合后的综合算法,在率失真性能几乎保持不变的情况下,帧内编码速度提高超过70%以上。 相似文献
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Changnian Chen Jiazhong Chen Kun Ouyang Tao Xia Jingli Zhou 《Multimedia Tools and Applications》2013,62(3):719-731
It has been well demonstrated that edge information can be utilized for intra mode decision in H.264/AVC to reduce the computational complexity. In spite of the remarkable speedup for mode decision, the existing edge detection based solution always shows relatively high coding loss due to inaccurate mode selection. In this work, a novel fast intra mode decision based on a more precise direction representation scheme is proposed, which exploits the gradation along the prediction direction as well as the differential between the original pixels and their predicted ones. Extensive experimental results show that the proposed method can averagely achieve about 0.05 dB peak signal-to-noise ratio (PSNR) gain and 1.1% bit rate (BR) decrease with negligible computational complexity increase, compared with the state-of-the-art edge detection method. 相似文献
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H.264/AVC视频编码标准中用率失真优化(RDO)方法为一个宏块(MB)判决最佳编码模式来提高编码效果,加大了算法复杂度并且计算冗余大。为了克服这一缺点,一种快速帧内预测模式选择算法被提出。在色度预测中,根据宏块的色度纹理复杂度,把原先的4种模式降到1或2种;在亮度16×16块模式判决中,根据最小哈达玛变换的绝对误差和(SATD)来选择最佳模式;在亮度4×4块模式判决中,该算法在9种模式中选择3种可能模式作为候选模式。通过比较16个4×4块总代价与1个16×16块的代价来选择最佳块选择模式,实验表明,该算法能在节省69%左右编码时间的情况下,比特率与峰值信噪比(PSNR)保持不变。 相似文献
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帧内编码是H.264标准的一个重要组成部分,针对原标准的全搜索算法运算复杂度高,不能支持实时视频需要的问题,提出了一种基于模板和双阈值的快速算法,可以有效地减少计算复杂度。实验结果表明该算法可以在信噪比和码率变化不大的情况下,使编码时间平均减少42%。 相似文献
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H.264/AVC帧内4×4块预测模式选择算法的研究 总被引:1,自引:0,他引:1
在分析H.264帧内预测技术的基础上,提出了一种快速的帧内4×4块预测模式选择算法.该算法计算当前4×4块与空间/时间相邻4×4块之间的相似程度,判断是否跳过其模式选择过程;对未跳过的4×4块,根据变换系数的绝对差值和(SATD)信息及空间/时间相关性,排除一些可能性小的预测模式.实验表明,与JM10.2相比,对于IIII及IPPP编码结构:编码时间平均减少了44.07%和20.49%,码率和Y分量的信号噪声比(SNRY)基本不变. 相似文献
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为降低H.264帧内预测模式的计算复杂度,提出了一种率失真优化(RDO)准则下的基于边缘特征的快速帧内模式选择算法。该算法根据主要边缘强度(KES)等边缘方向特征,选择出与该特征相对应的模式子集进行RDO计算,大幅度降低了帧内预测的模式选择数;同时将亮度宏块和色度宏块分别优化以降低计算复杂度。仿真结果表明,与原H.264相比,所提出的算法在比特率略有增加和信噪比基本保持不变的条件下,大约减少75%的计算时间,大大降低了算法的计算复杂度;与PAN FENG等人提出的基于Sobel算子的边缘矢量检测算法相比,两者的比特率基本相同,但算法的平均峰值信噪比明显高于PAN的算法,编码时间也有明显降低,同时运算简单规则,更易于VLSI的实现。 相似文献
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一种用于H.264的快速帧内预测模式判别方法 总被引:1,自引:0,他引:1
提出了一种快速帧内预测模式判别的方法来减少H.264中帧内预测模式判别的时间。H.264采用拉格朗日率失真优化(RDO)模式判别方法来对帧内预测模式进行判别,但由于H.264提供了大量的帧内编码模式,使得计算量非常大,目的是在RD性能没有明显下降的情况下,减少帧内预测的计算量。提出的快速模式判别方法采用绝对变换差值和(SATD)以及绝对梯度和(SAG),来减少4×4和8×8块的帧内预测模式的数目,从而提高模式判别的速度。实验结果表明,该算法在编码增益减少不大的情况下,I帧的编码时间减少了50%~70%,整体的编码时间减少了大约10%~20%。 相似文献
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为了进一步减小宏块的帧间预测误差,新的视频编码标准H.264/AVC采用了可变块划分运动估计,极大地增加了编码器的复杂度.针对此问题,提出了一种快速的帧间模式选择算法,该算法利用已编码相邻宏块的时间和空间相关性信息预先检测图像,对图像各区域可能采用的编码模式进行判定,从而大大简化了模式选择的过程.实验结果表明,算法可以在图像质量基本保持不变的基础上,有效地降低编码的复杂度. 相似文献
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针对H.264帧内模式决策,提出一种快速算法。对于亮度分量,该算法根据待编码宏块平滑度的特点来设定条件,满足平滑条件则直接判断出采用intra_16×16四种预测模式中的哪种模式,对于不符合条件的采用intra_4×4预测模式,此时可以剔除部分不常用的预测模式;对于色度分量,可以根据人眼对色度不敏感这个客观事实来减少候选模式的数量,从而进一步降低编码时间。实验结果表明,该算法可以节省30%以上的编码时间,同时保持相似的视频质量。 相似文献
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Intra coding in H.264/AVC can significantly improve the compression efficiency but at the cost of high computational complexity. To reduce the complexity, this paper presents an efficient block type decision algorithm for intra prediction. In H.264/AVC high profile, three kinds of block types are supported. This algorithm determines the optimal block type by two steps. The first step is based on the fact that the block type of intra prediction is highly dependent on the smoothness of macroblock. An edge-based feature is introduced to characterize the smoothness, by comparing it with two thresholds impossible block type is firstly filtered out. Then the second step is based on the correlation of block type chosen for different chroma modes. Experimental results show that the proposed fast algorithm can achieve 72.8% time saving on average for encoding the all intra-frame sequence with average 0.75% bit rate increase and 0.05dB PSNR degradation when comparing with the reference software. 相似文献
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为了减小H.264的编码算法复杂度,提出了一种快速的帧内模式选择算法。根据中心8×8块边界信息判定宏块预测类型,利用改进的pan算法对选定了预测类型的宏块进行模式筛选,采取RDO准则选出最佳的预测模式。实验结果表明:对全I帧序列,与JM10.2中全模式遍历算法相比较,该算法编码时间平均减少了大约70%,而码率和峰值信噪比基本不变。与pan算法相比,编码时间减少最大超过40%。因此,该算法更便于实时应用。 相似文献
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As one of the main features of H.264/AVC, intra prediction coding technique acts as a basis for encoding performance and efficiency.
In official reference software Joint Model (JM), it employs the rate distortion optimization (RDO) technique to get to the
best encoding performance. By full searching (FS) all of the candidate modes under the rule of RDO, peak-signal-noise-rate
(PSNR) decreases to a very low level, but at the same time, the complexity of calculation increases a lot. Many researchers
had devoted to searching the fast algorithm which can decrease the complexity, and had designed so many excellent and intelligent
fast algorithms. In this paper we introduced a low complexity and fast approach for H.264/AVC intra prediction algorithm.
The new approach is based on reducing the number of candidate modes for further RDO calculation, and decreasing the computational
complicacy. It can decide the interpolation direction accurately by calculating the directional pixel-value differences (DPD)
of target block, and then do statistic with the obtained values to choose the most probable modes. The experimental results
demonstrate that the proposed algorithm can achieve more than 70% time saving than JM, but only a tiny degradation of encoding
performance is brought in. 相似文献
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Changnian Chen Jiazhong Chen Tao Xia Zengwei Ju Lai-Man Po 《Multimedia Tools and Applications》2014,72(1):687-704
In this paper, an improved hybrid fast mode decision method for H.264/AVC intra coding is proposed, which is based on the analysis of edge filter and more efficient mode selection. In contrast to the conventional fast mode decision methods where multiple neighbor modes are determined by the same filter, a unique filter is applied to each directional mode to eliminate the correlation among neighbor modes. To reduce the complexity, the filters are only applied to the selected pixels that cover most of the block region. After that, the results along prediction residuals of these pixels are summed for fast mode decision. Moreover, local information is also taken into account through Most Probable Mode (MPM) from neighbor-coded blocks. Experimental results demonstrated that better coding performance is achieved as compared with well-known conventional fast mode decision algorithms for H.264/AVC intra coding. 相似文献
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H.264/AVC标准采用可变块运动估计和率失真优化技术进行帧间模式选择,提高了编码效率,但极大地增加了计算复杂度。为了解决这一问题,提出一种快速帧间模式选择算法,它利用了SKIP模式在视频序列中的使用率信息和时空域相邻宏块与当前宏块编码模式之间的高度相关性。该算法缩小了模式选择的范围,并采用阈值来提高预测准确度。仿真结果表明,该算法在保持图像质量和比特率的前提下可以大幅度减少计算复杂度。 相似文献