共查询到20条相似文献,搜索用时 15 毫秒
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为H.264/AVC标准的可伸缩编码(SVC)扩展提出了一种自适应的层间码率控制算法。该算法提出了一个选择模型,通过当前层的前一帧或者前一层的当前帧来预测Inter帧所需比特数。首先,将码率—复杂度—量化因子(R-C-Q)模型引入可伸缩的视频编码;接着,使用一个已有的比例—积分—微分(PID)缓冲区控制器来根据缓冲区状态提供当前Inter帧的比特数估计;然后,为了在视频画面发生急剧变化时获得更为精确的估计,利用前一层中的当前帧所用实际比特数来进一步进行当前Inter帧比特数估计;最后,使用选择模型决定最终的预测比特数,并通过R-C-Q模型计算出量化因子(QP)。实验结果表明,相对于推荐的JVT-043码率控制算法,所提出的算法可以在SVC的每层获得更加精确的实际输出比特率,保持缓冲区充盈度的稳定,同时减少跳帧和质量波动,提高整体编码质量。 相似文献
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基于可伸缩视频编码的率失真优化编码算法* 总被引:1,自引:0,他引:1
可伸缩视频编码(SVC)可实现视频流空间、时间和信噪比的完全伸缩,但在差错信道上传输容易引起误差扩散,为此提出一种基于SVC的率失真优化编码算法。该算法在分析了差错信道下传输可伸缩视频流误差扩散失真的基础上,在率失真优化模型中引入时间和信噪比分级的误差分级参数,并根据信道状态自适应地确定宏块编码模式。该算法能够有效地抑制误码在各分层的扩散,提高了可伸缩视频流的鲁棒性。仿真结果表明,算法与以往的算法相比具有更好的抗误码性能,适合视频数据在差错信道上的传输。 相似文献
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多媒体及Internet的迅速发展促使视频编码不仅要有较好的容错性能,而且要根据网络带宽和接收设备的特性而自适应地进行调整和传输。多描述编码可以提高视频传输的容错性能但不具有网络自适应性;可分级编码能够根据网络带宽和接收设备的特性而自适应地进行调整和传输但不具有容错性能。综合了多描述编码和可分级编码优势的多描述可分级编码,则不但具有网络带宽的自适应性,同时具有很好的容错性能。在分析了多描述编码和可分级编码的各自局限性的基础上,重点介绍了多描述可分级编码的产生和几种实现策略。 相似文献
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为提高可伸缩视频编码(SVC)在丢包的网络传输环境下的抗误码性能,提出了一种基于自适应遗传算法的SVC非均等错误保护算法。首先针对可伸缩视频编码的网络抽象层单元数据包头的特点,设计了一种新的网络抽象层单元的封装方案。然后将前向纠错编码的校验位在各层的分配转化为多约束条件下的优化问题,再引入惩罚函数将多约束优化问题转化为无约束优化问题,进而采用自适应遗传算法进行求解。仿真实验结果表明,与目前典型的非均等错误保护算法相比,该算法使重建的可伸缩视频编码的峰值信噪比的平均值提高了0.8dB~1.95dB,并有效提高了可伸缩视频编码在接收端的解码速度和重建质量。 相似文献
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完全可伸缩视频编码的实现和改进* 总被引:1,自引:0,他引:1
提出了一种完全可伸缩视频编码的改进方法。首先给出了一种采用运动补偿时域滤波、二维离散小波变换和EZW编码的传统可伸缩编码方案,该方案将时间、空间、质量三方面的伸缩性有机地结合在一起,实现了完全可伸缩性能。针对运动补偿时域滤波技术中的GOP(group of pictures)结构和更新操作进行了改进,引入GOP结构自适应选择,降低系统内存需求和运算复杂度;采用基于人眼视觉系统特性的最小可觉差对更新操作中所引进的误差进行内容自适应修正。实验结果表明,编码效率和视频序列的重建质量都得到了显著的提高。 相似文献
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Although scalable video coding can achieve coding efficiencies comparable with single layer video coding, its computational
complexity is higher due to its additional inter-layer prediction process. This paper presents a fast adaptive termination
algorithm for mode selection to increase its computation speed while attempting to maintain its coding efficiency. The developed
algorithm consists of the following three main steps which are applied not only to the enhancement layer but also to the base
layer: a prediction step based on neighboring macroblocks, a first round check step, and a second round check step or refinement
if failure occurs during the first round check. Comparison results with the existing algorithms are provided. The results
obtained on various video sequences show that the introduced algorithm achieves about one-third reduction in the computation
speed while generating more or less the same video quality.
相似文献
Jianfeng RenEmail: |
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《Displays》2015
A scalable video coding (SVC) server can simultaneously provide a single bitstream with a fixed maximum service layer for different kinds of devices having different memory capacity, network bandwidth, and CPU performance requirements. An efficient hybrid 3D video service scheme is proposed without violation of the SVC standard technology for multiple transmission paths. A dynamic local disparity vector estimation algorithm is used to reflect the motion shift component between stereo views in the inter-layer prediction stage of the SVC encoder. To improve the coding efficiency, an adaptive search scheme based on distortion rates (DRs) between corresponding and reference macroblocks is used. Based on experimental results, up to 1.41 dB of quality improvement using JSVM 9.19 reference software is verified. 相似文献
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针对可分级视频编码(SVC)技术中层间残差预测(ILRP)大大增加了编码复杂度的问题,提出一种快速算法。带残差的帧间预测和不带残差的帧间预测都采用全搜索的预测算法,编码复杂度很大,所提算法分析了增强层带残差的帧间预测和不带残差的帧间预测之间的率失真代价(RDCost)差异,动态判定增强层是否需要采用层间残差预测以减少层间残差预测过程;同时依据层间预测模式相关性,利用基本层最优帧间预测模式指导增强层最优帧间预测模式的选择过程,进一步节省编码时间。实验结果表明,与参考模型JSVM中的算法相比,改进的快速算法在编码质量降低小于0.01dB,码率提高不大于3%的前提下,可节省平均编码时间50%左右,有效地降低了编码复杂度,对于编码器的优化方面有理论参考价值和实际应用意义。 相似文献
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针对不可控网络下的视频应用,提出一套新的小波视频编码方案,适用于根据每个用户实时网络状况进行动态码率传输和控制,目的是为用户在不稳定的带宽下提供持续清晰流畅的全局最优的视频体验。该编码方案简化了W5/3提升小波,在MCTF算法中引入层次化多参考帧预测,并采用新提出的基于优先级的传输层流打包方法以及基于块位长的嵌入式零块编码算法。经过测试表明,提出的算法压缩效率高,质量可伸缩性好,能够有效提升用户体验。 相似文献
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Luis Herranz 《Multimedia Systems》2007,13(2):103-118
Scalable video coding has become a key technology to deploy systems where the adaptation of content to diverse constrained
usage environments (such as PDAs, mobile phones and networks) is carried out in a simple and efficient way. Content-based
adaptation and summarization are fields that aim for providing improved adaptation to the user, trying to optimize the semantic
coverage in the adapted/summarized version. This paper proposes the integration of content analysis with scalable video adaptation
paradigm. They must be fitted in such a way that the efficiency of scalable adaptation is not damaged. An integrated framework
is proposed for semantic video adaptation, as well as an adaptive skimming scheme that can use the results of semantic analysis.
They are described using the MPEG-21 DIA tools to provide the adaptation in a standard framework. Particularly, the case of
activity analysis is described to illustrate the integration of semantic analysis in the framework, and its use for online
content summarization and adaptation. Overall efficiency is achieved by means of computing activity using compressed domain
analysis with several metrics evaluated as measures of activity.
Work supported by the Ministerio de Ciencia y Tecnología of the Spanish Government under project TIN2004-07860 (MEDUSA) and
by the Comunidad de Madrid under project S-0505-TIC-0223 (PROMULTIDIS). 相似文献
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The next generation space internet (NGSI) is based on all-IP-based mobile network that merges land-based network, sea-based network, sky-based network, spacebased network, deep space-based network together using existing assess network technologies. There are high signal propagation delays, high error rate, bandwidth variation and time-variety in NGSh In order to adapt to various space communication environment constraints and bandwidth variation, we propose a reduced dimension scalable video coding scheme based on CCSDS IDCS algorithm and quality of service (QoS) control method by cross layer design (CLD). The experimental result shows that this new method has better performance than that of existing algorithms, and can be adaptive to the bandwidth variation dynamically. 相似文献
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《Displays》2019
Conventional video coding standards, such as MPEGx and H.26x, use a hybrid architecture of block-based motion compensation and discrete cosine transform (DCT) within the structure of a complex encoder and a simple decoder. Contrary to conventional video codecs, Wyner-Ziv (WZ) video coding, which is a practical application of distributed video coding (DVC) based on the Slepian-Wolf and WZ theorems, exploits the source correlation at the decoder, thereby allowing for the development of simpler encoders. However, the current WZ video coding algorithms cannot match the coding performance of conventional video coding. In order to improve the coding performance of transform-domain WZ video coding, an adaptive two-step side-information generation method is thus proposed for evaluation and analysis in this study. The proposed method uses decoded WZ frames in the down-sampled spatial resolution along with already decoded coefficients to successively improve rate-distortion (RD) performance as the decoding progresses. The experimental results show that the proposed method, compared to previous WZ video coding method, shows improved coding performance, particularly under critical conditions, such as cases with high motion content. 相似文献
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提出了一种完全可伸缩视频编码的实现方法。给出了一种采用运动补偿时域滤波、二维离散小波变换和EZW编码的可伸缩编码方案,方案根据视频图像运动特征自适应选择图组结构,在将时间、空间、质量三方面的伸缩性有机地结合的同时,改进了完全可伸缩视频编码系统性能。最后给出了该方案的实验结果,表明了系统的有效性。 相似文献
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基于MPEG-4标准FGS可分级技术,提出一种将FGS可分级、视点可分级相结合的多视点立体视频可分级算法。该算法中,中间视点作为基本层进行编码,各视点均预测自中间视点,并产生各相应视点的FGS增强层。编码器结构中,分为I、P、B帧三种情况进行讨论,并针对这三种情况进行改进。所提方案具有灵活、广泛的可分级性能,能适应多种不同的传输需求。实验结果验证了该方案的多视点可分级性。 相似文献
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目的新一代高效视频编码(HEVC)标准采用了灵活的块结构和大量新颖的编码工具,有效提高了视频编码效率。变换跳过模式作为一种新增加的模式,可以有效地提高编码效率,但是也显著地增加了编码的复杂度,增加了实时编码应用的难度。因此提出一种针对变换跳过模式的提前剪枝算法。方法通过分析不同率失真代价下是否选择变换跳过模式的残差块的分布情况,最终选取率失真代价的平方根作为阈值,并建立了量化参数与阈值之间的模型。之后可以根据量化参数提前计算得到阈值大小,减少变换跳过模式的编码次数,从而降低变换跳过模式的复杂度。结果由于最终只需要对少量的块进行变换跳过模式编码,并且使用模型得到经验阈值并不会额外增加复杂度,因此能减少编码器的计算复杂度。实验结果表明,与标准编码器相比,该算法对于不同场景的标准测试序列平均峰值性噪比和平均比特率变化都非常小,平均减少了70%的变换跳过模式编码的次数。结论该变换跳过模式的剪枝算法,选取率失真代价的平方根作为阈值,根据本文模型获取不同量化参数下的经验阈值,对是否需要进行变换跳过模式提前判断。实验结果表明,该算法能在保证视频编码质量的前提下有效地降低由于加入变换跳过模式增加的编码复杂度。 相似文献
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为了提高质量可伸缩高性能视频编码(SHVC)的编码速度,提出一种基于质量SHVC的帧内预测算法。首先,利用层间相关性来预测可能的深度,排除可能性较小的深度;其次,对可能的编码深度,采用层间预测(ILR)模式进行编码,并对得到的残差系数进行分布拟合检验,判断是否满足拉普拉斯分布从而跳过帧内模式;最后,对深度编码得到的深度残差系数判断是否满足深度提前终止判断条件,如果满足该条件则提前终止以提高编码速度。实验结果表明,所提算法能够在保证编码效率损失很小的情况下使编码速度提高79%。 相似文献
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在详细分析高效率视频编码标准HEVC现有码率控制算法JCTVC-H0213的基础上,提出了一种快速有效的改进算法。该算法根据前一帧的目标比特和实际比特的比值来确定当前帧量化参数。在恒定比特率情况下将该算法与JCTVC-H0213进行比较,实验结果表明该算法对于大部分内容特性序列峰值信噪比变化值提高2.4dB以上,达到了很好的码率控制效果;并且该算法非常简单,适用于实时的码率控制应用。 相似文献