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视频流传输中的差错复原视频编码技术 总被引:2,自引:1,他引:2
视频压缩技术在采用预测技术、变换编码技术和可变长熵编码技术以减少冗余信息的同时,也降低了视频流的容错能力.传输信道中的差错,不仅严重损害了视频服务质量,甚至会使通信系统崩溃,因此,在有错信道上进行视频传输,差错复原视频编码技术就显得尤为重要.对差错复原视频编码技术进行了概括和总结,首先指出在视频传输过程中存在的由于传输错误而引发的比特流同步丢失及错误蔓延问题,然后研究了解决这些问题的差错复原视频编码方法,最后指出:可伸缩视频编码和多描述视频编码是差错复原视频编码的发展方向;多描述编码同多路径技术相结合,能显著提高压缩视频信号的错误恢复能力和传输信道的性能. 相似文献
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本文提出一种新的空间域帧间编码方法-预测信号梯度控制的四叉树编码,模拟实验表明,这种编码方法的效率已经与DCT相当,并稍有超出,而其算法比较简单。 相似文献
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基于无线视频监控传输技术进行无线信道视频图像传输的过程中,经常面临数据传输错误、带宽变化、网络拥塞导致的视频数据丢失问题,严重影响了图像质量。Joint Video Team(JVT)of ISO/IECMPEG and ITU-T VCEG提出了可伸缩视频编码(SVC),可实现视频空间、时间和图像质量的完全伸缩,本文结合率失真优化算法将可伸缩编码作为容错工具,引入了不同层数据,根据B-D代价函数决定自动重传机制,降低了视频数据丢失对图像质量的影响。仿真结果表明,该方法大大提高了视频码流的抗误码能力和传输的鲁棒性。 相似文献
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本文提出了采用树结构矢量组合对小波图像进行分类矢量量化的新方法.该方法充分利用了子带系数的带间和带内的相关性,分类信息占用比特数少,并采用了基于人眼视觉特性的加权均方误差准则进行矢量量化,提高了量化增益.仿真结果表明,该方法实现简单,可达到很好的压缩效果. 相似文献
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The visual quality is a critical factor in prediction video coding over packet-switched networks. However, the traditional MSE-based error resilient video coding cannot correlate well with the perceptual characteristics of the human visual system (HVS). This paper proposes a structural similarity (SSIM) based error resilient video coding scheme to improve the visual quality of compressed videos over packet-switched networks. In the proposed scheme, a SSIM-based end-to-end distortion model is developed to estimate the perceptual distortion due to quantization, error concealment, and error propagation. Based on this model, an adaptive mode selection strategy is presented to enhance the communication robustness of compressed videos. Experiments show that the proposed scheme significantly improves the visual quality for H.264/AVC video coding over packet-switched networks. 相似文献
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视频子带信号的正交镜像滤波和亚取样会造成运动补偿信息失配和频谱混叠,使预测误差增加并导致视频子带编码系统效率下降。本文对此现象进行了分析,提出了解决这一问题的改进方案。 相似文献
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Rate-Distortion Optimized Motion-Compensated Prediction for Packet Loss Resilient Video Coding 总被引:1,自引:0,他引:1
A rate-distortion optimized motion-compensated prediction method for robust video coding is proposed. Contrasting methods from the conventional literature, the proposed approach uses the expected reconstructed distortion after transmission, instead of the displaced frame difference in motion estimation. Initially, the end-to-end reconstructed distortion is estimated through a recursive per-pixel estimation algorithm. Then the total bit rate for motion-compensated encoding is predicted using a suitable rate distortion model. The results are fed into the Lagrangian optimization at the encoder to perform motion estimation. Here, the encoder automatically finds an optimized motion compensated prediction by estimating the best tradeoff between coding efficiency and end-to-end distortion. Finally, rate-distortion optimization is applied again to estimate the macroblock mode. This process uses previously selected optimized motion vectors and their corresponding reference frames. It also considers intraprediction. Extensive computer simulations in lossy channel environments were conducted to assess the performance of the proposed method. Selected results for both single and multiple reference frames settings are described. A comparative evaluation using other conventional techniques from the literature was also conducted. Furthermore, the effects of mismatches between the actual channel packet loss rate and the one assumed at the encoder side have been evaluated and reported in this paper 相似文献
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The performance of Motion Compensated Discrete Cosine Transform (MC‐DCT) video coding is improved by using the region adaptive subband image coding [18]. On the assumption that the video is acquired from the camera on a moving platform and the distance between the camera and the scene is large enough, both the motion of camera and the motion of moving objects in a frame are compensated. For the compensation of camera motion, a feature matching algorithm is employed. Several feature points extracted using a Sobel operator are used to compensate the camera motion of translation, rotation, and zoom. The illumination change between frames is also compensated. Motion compensated frame differences are divided into three regions called stationary background, moving objects, and newly emerging areas each of which is arbitrarily shaped. Different quantizers are used for different regions. Compared to the conventional MC‐DCT video coding using block matching algorithm, our video coding scheme shows about 1.0‐dB improvements on average for the experimental video samples. 相似文献
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《IEEE transactions on image processing》2008,17(12):2347-2355
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视频信号在基于运动补偿预测的混合编码后,在不可靠信道中传输时会遇到严重的误码传播问题.本文从理论上分析了一种广义的运动补偿预测技术--多参考运动补偿预测的误码传播和编码效率,得到了由误码传播引起的失真和编码效率的理论极限,并给出了某些假设条件下理论极限的值.通过理论分析和对几种特定的基于多参考运动补偿预测的混合编码方案在INTERNET丢包环境中的仿真,我们发现采用多参考运动补偿预测可以同时减小误码传播失真和提高编码效率. 相似文献
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This paper is concerned with motion compensation techniques for predictive coding of the composite (frequency multiplexed) color television signal. Motion estimation algorithms developed in this paper are recursive and are extensions of our previous algorithms developed for baseband luminance signals. We show, by computer simulations, that displacement of objects from frame to frame can be estimated in the composite signal domain without decomposing the composite signal into its original components. However, due to the poorer quality of displacement estimation and the resulting prediction, motion compensation in the composite signal domain is not as efficient as motion compensation in the component domain. Simulations indicate that a motion compensated predictive coder requires, in some cases, up to 25 percent fewer bits than a coder that uses previous field prediction. 相似文献
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We develop and evaluate motion compensation schemes for predictive coding of the component color television signal. Algorithms are discussed for estimation of motion of each color component (luminance and chrominance) separately as well as in combination. Techniques for switching of the predictors for individual components are proposed and simulated. Simulations show that it is sufficient to estimate parameters of motion based only on the luminance and use them for motion-based prediction and switching the predictors for both the luminance and chrominance. Thus, only one motion estimator and prediction switch is needed for the three components of the color signal. Compression capability of motion compensation is scene dependent, in some video conference type of scenes, bit rate is reduced by as much as 60 percent compared to conditional replenishment coding. 相似文献
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视频编码新标准H.264中抗误码技术的研究 总被引:3,自引:0,他引:3
介绍了视频编码新标准--H.264中采用的几种抗误码技术,基于这些技术,新标准确保了压缩视频流在接收端的恢复质量. 相似文献
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介绍了视频编码新标准———H .2 6 4中采用的几种抗误码技术 ,基于这些技术 ,新标准确保了压缩视频流在接收端的恢复质量。 相似文献
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Interframe motion estimation of subblocks based on improved search techniques is developed. These techniques are based on minimizing the mean difference between the subblock in question in the present frame and the displaced subblock in the previous frame. The performance of the motion compensated prediction developed here is investigated for various block sizes and is compared to other techniques. 相似文献
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Liwei Guo Oscar C. Au Mengyao Ma Zhiqin Liang 《Journal of Signal Processing Systems》2010,60(3):273-290
Multi-Hypothesis motion compensated filter (MHMCF) utilizes a number of hypotheses (temporal predictions) to estimate the current pixel which is corrupted with noise. While showing remarkable denoising results, MHMCF is computationally intensive as full search is employed in the expectation of finding good temporal predictions in the presence of noise. In the frame of MHMCF, a fast denoising algorithm FMHMCF is proposed in this paper. With edge preserved low-pass prefiltering and noise-robust fast multihypothesis search, FMHMCF could find reliable hypotheses while checking very few search locations, so that the denoising process can be dramatically accelerated. Experimental results show that FMHMCF can be 10 to 14 times faster than MHMCF, while achieving the same or even better denoising performance with up to 1.93 dB PSNR (peak-signal-noise-ratio) improvement. 相似文献