共查询到17条相似文献,搜索用时 62 毫秒
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当H.263编码视频流在Internet上传输时,很容易受到信道错误的影响而丢失数据,由于数据的丢失不但会影响当前帧,还会连续传递到以后的解码帧,而导致图象质量的严重恶化,因此必须采用一定的措施来消除这种影响。目前较常用的错误掩盖算法是时域掩盖算法,而时域掩盖算法是利用参考帧来恢复当前帧损坏的图象数据,其计算较复杂,为此,提出了一种基于块匹配原则的时域掩盖算法,同时用三步搜索代替完全搜索来降低算法的计算复杂性,模拟结果显示,该算法由于能够在很短的处理时间内,获得较好质量的图象,因此能适应于视频会议等实时应用的要求。 相似文献
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基于TM1300的H.263编码器的实现 总被引:2,自引:0,他引:2
为了实现实时甚低比特率视频编码器,提出了基于TM1300实现的H.263编码器算法改进和优化的关键方法,总结出TM1300上优化改进算法的一些方法和经验,并由此实现了实时的H.263编码器,达到了较好的效果。 相似文献
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结合H.263与SLCCA的新的极低比特率小波视频编码 总被引:2,自引:0,他引:2
小波对于静止图像编码取得了巨大成功,但对于视频编码只有少数较为成功的尝试,提出一种针对极低比特率应用的新的结合H.263与SLCCA的混合小波视频编码算法,在提出的算法中,首先,用基于H.263的微调运动估计减少时间冗余,用无遗漏覆盖块运动补偿保证运动补偿误差帧的连续性;第2,对运动补偿误差帧进行小波变换得到全局能量压缩;第3,用SLCCA组织和表示小波变换后的数据;最后,运动向量的水平和垂直分量分别用自适应算法编码,算法在A级测试序列Akiyo和B级测试序列Foreman(QCIF)上测试取得了良好效果。 相似文献
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提出一种新的MPEG-2到H.264快速转码算法,利用H.264宏块(MB)模式选择与MPEG-2运动补偿残差间的相关性,将H.264宏块模式的选择转化为数据分类;在MPEG-2解码时,保存相关的宏块信息,包括MB编码模式、编码块类型(CBPC)、MB残差的均值和方差,解码后采用标准的H.264编码器对YUV图像编码,并保存H.264宏块的编码模式,采用机器学习算法得到决策树,用于H.264编码模式的分类,从而大大提高转码效率。 相似文献
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MPEG-2视频编码的运动估计与实现 总被引:1,自引:0,他引:1
MPEG┐2视频编码的运动估计与实现陈维强高文(哈尔滨工业大学计算机科学与工程系哈尔滨150001)关键词运动图象压缩,MPEG-2,运动估计.1)国家863计划智能计算机系统主题和国家“九五”攻关计划的支持项目.收稿日期1997-06-031引言M... 相似文献
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In the past 10 years detailed works on different video transcoders have been published. However, the new ITU-T Recommendation
H.264—also adapted as ISO/IEC MPEG-4 Part 10 (AVC)—provides many new encoding options for the prediction processes that lead
to difficulties for low complexity transcoding. In this work we present very fast transcoding techniques to convert H.263
bitstreams into H.264/AVC bitstreams. We will give reasoning, why the proposed pixel domain approach is advantageous in this
scenario instead of using a DCT domain transcoder. Our approach results in less than 9% higher data rate at equivalent PSNR
quality compared to a full-search approach. But this rate loss allows the reduction of the search complexity by a factor of
over 200 for inter frames and still a reduction of over 70% for intra frames. A comparison to a fast search algorithm is given.
We also provide simulation results that our algorithm works for transcoding MPEG-2 to H.264/AVC in the aimed scenario.
相似文献
André KaupEmail: |
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Jun Xin Jianjun Li Anthony Vetro Shun-ichi Sekiguchi 《Multimedia Tools and Applications》2007,35(2):203-223
This paper describes novel transcoding techniques aimed for low-complexity MPEG-2 to H.264/AVC transcoding. An important application
for this type of conversion is efficient storage of broadcast video in consumer devices. The architecture for such a system
is presented, which includes novel motion mapping and mode decision algorithms. For the motion mapping, two algorithms are
presented. Both efficiently map incoming MPEG-2 motion vectors to outgoing H.264/AVC motion vectors regardless of the block
sizes that the motion vectors correspond to. In addition, the algorithm maps motion vectors to different reference pictures,
which is useful for picture type conversion and prediction from multiple reference pictures. We also propose an efficient
rate-distortion optimised macroblock coding mode decision algorithm, which first evaluates candidate modes based on a simple
cost function so that a reduced set of candidate modes is formed, then based on this reduced set, we evaluate the more complex
Lagrangian cost calculation to determine the coding mode. Extensive simulation results show that our proposed transcoder incorporating
the proposed algorithms achieves very good rate-distortion performance with low complexity. Compared with the cascaded decoder-encoder
solution, the coding efficiency is maintained while the complexity is significantly reduced.
相似文献
Shun-ichi SekiguchiEmail: |
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H.263无线视频传输的关键技术改进 总被引:2,自引:0,他引:2
移动多媒体业务是当前移动数据通信的研究热点。视频信号处理需要大量的运算,要求较宽的传输带宽。目前移动网络上的视频传输存在着网络带宽有限、误码严重、终端处理能力较弱等问题。基于H.263提出了提高编码效率、增强抗干扰能力的编解码算法优化方案,有效地提高了运算效率,提升了解码视频的主客观质量。 相似文献
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Gerardo Fernández-Escribano Pedro Cuenca Luis Orozco-Barbosa Antonio Garrido Hari Kalva 《Multimedia Tools and Applications》2008,38(1):1-25
Recent developments have given birth to H.264/AVC: a video coding standard offering better bandwidth to video quality ratios
than MPEG-2. It is expected that the H.264/AVC will take over the digital video market, replacing the use of MPEG-2 in most
digital video applications. The complete migration to the new video-coding algorithm will take several years given the wide
scale use of MPEG-2 in the market place today. This creates an important need for MPEG-2/H264 transcoding technologies. However,
given the significant differences between both encoding algorithms, the transcoding process of such systems is much more complex
to other heterogeneous video transcoding processes. In this work, we start by analyzing the methods defined in the H.264 video
coding standard for the intra prediction: a central element of every H.264 encoder. We then introduce and evaluate six fast
intra mode decision algorithms which should enable the development of MPEG-2 to H.264 transcoders. Having evaluated all the
proposed methods, we have come out with a high-efficient method, namely DC-ABS pixel. Our results show that our algorithm
considerable reduces the complexity involved in the intra prediction with respect the mode decision algorithms used in H.264
JM reference software, while exhibiting a slight degradation on the RD function.. Finally, we analyze a comparative study
with two of the most prominent fast intra prediction methods presented in the literature. The results show that the proposed
DC-ABS pixel method achieves the best results for video transcoding applications.
相似文献
Hari KalvaEmail: |
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本文提出一种新的MPEG-2到H.264的视频转码算法.它通过充分利用MPEG-2解码过程中得到的运动矢量和宏块编码残差等信息,可显著减少H.264编码过程中宏码编码模式确定和运动估计过程的计算复杂度,并得到最终的H.264视频流.几种典型视频测试序列的仿真实验结果表明,本算法对视频质量的损失较小,有稳定的率失真性能,有利于实时转码的实现. 相似文献