共查询到18条相似文献,搜索用时 156 毫秒
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概述了AVS视频编解码标准的帧内预测技术,重点分析了帧内预测各种预测模式的算法,并将AVS的帧内预测技术和H.264/AVC标准的帧内预测技术进行了算法复杂度和性能的比较.在此基础上,设计了一种AVS帧内预测模块的硬件实现.并提出了一种可并行处理的计算单元结构. 相似文献
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提出梯度方向算子的概念,基于该算子提出了一种H.264帧内模式快速选择算法。本文首先应用梯度方向算子计算编码宏块中各4×4亮度子块的纹理特征和灰度起伏特征,根据这两种特征参量削减4×4帧内候选预测模式。通过统计宏块中各子块的4×4候选预测模式信息,结合梯度方向强度门限判别法削减宏块的16×16候选预测模式,通过率失真优化算法计算得到最优亮度预测模式。进一步根据亮度宏块和色度宏块的对应关系,在亮度候选预测模式的基础上对色度宏块候选预测模式进行削减,最后计算得到最优色度预测模式。该算法削减了50%以上的帧内预测模式,减少了帧内预测模式选择的运算量,实验表明,该算法能够在峰值信噪比和码流比特率变化轻微的前提下减少50%以上的运算量。 相似文献
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一种新的H.264/AVC快速帧内预测模式选择判决算法 总被引:3,自引:0,他引:3
针对H.264视频编码标准帧内预测模式选择部分计算量大的问题,本文提出了一种快速帧内预测模式选择判决算法。该算法首先提出了一个新的算子,用来描述图像灰度分布信息,作为判断图像复杂程度的依据,进而提出两个对量化系数(QP)自适应的阈值,将图像分为平滑、变化剧烈和特征模糊3种。平滑图像宏块使用Intra_1616模式预测,变化剧烈的宏块使用Intra_44模式预测,特征模糊的宏块使用标准算法预测。实验结果表明,该优化算法能在保证很好的图像质量的同时,使帧内模式选择计算次数减少30%以上,而且对传输码率基本没有影响。 相似文献
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,H.264标准中亮度分量的9种帧内预测模式的序号是预先设定的,这对于具体的视频序列并不是最优的.为了进一步提高帧内编码的效率,通过对帧内预测编码算法的深入研究,利用相邻宏块间的纹理相关性和预测模式的方向性,提出一种新的帧内预测模式编码算法.通过在和当前编码块纹理相关性最大的区域中动态的统计出各个预测模式的使用概率,然后根据预测模式使用概率的大小来计算当前块的最可能编码模式.实验结果表明:与H.264参考模型JM86相比,该算法可以显著提高当前图像块的最优预测模式和最可能预测模式的匹配概率,使预测模式信息编码所需要的比特数平均减少5%~7%,从而降低了编码后的码率,而峰值信噪比(PSNR)基本保持不变. 相似文献
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An architecture of entropy decoder,inverse quantiser and predictor for multi-standard video decoding
Leibo Liu Yingjie Chen Shouyi Yin Hao Lei Guanghui He Shaojun Wei 《International Journal of Electronics》2013,100(7):877-893
A VLSI architecture for entropy decoder, inverse quantiser and predictor is proposed in this article. This architecture is used for decoding video streams of three standards on a single chip, i.e. H.264/AVC, AVS (China National Audio Video coding Standard) and MPEG2. The proposed scheme is called MPMP (Macro-block-Parallel based Multilevel Pipeline), which is intended to improve the decoding performance to satisfy the real-time requirements while maintaining a reasonable area and power consumption. Several techniques, such as slice level pipeline, MB (Macro-Block) level pipeline, MB level parallel, etc., are adopted. Input and output buffers for the inverse quantiser and predictor are shared by the decoding engines for H.264, AVS and MPEG2, therefore effectively reducing the implementation overhead. Simulation shows that decoding process consumes 512, 435 and 438 clock cycles per MB in H.264, AVS and MPEG2, respectively. Owing to the proposed techniques, the video decoder can support H.264 HP (High Profile) 1920 × 1088@30fps (frame per second) streams, AVS JP (Jizhun Profile) 1920 × 1088@41fps streams and MPEG2 MP (Main Profile) 1920 × 1088@39fps streams when exploiting a 200 MHz working frequency. 相似文献
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文章比较了H.264和AVS两个标准在运动补偿中运动矢量预测算法的差别,提出了一种实现H.264中主档次(main profile)下的第4级别(level 4)和AVS中的基准档次面向高清应用时运动矢量预测复用的硬件结构.提出了一种新颖的缓存管理更新机制,极限情况下用于运动矢量的片上缓存大小减少了75%.用FPGA验证结果表明资源占用情况是单独实现AVS的2.3倍,是单独同时实现两个标准的70%.能实现对1080i 30Hz高清图像实时解码. 相似文献
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《Signal Processing: Image Communication》2009,24(4):324-332
Context-based Binary Arithmetic Coding (CBAC) is a normative part of the newest X Profile of Advanced Audio Video coding Standard (AVS). This paper presents an efficient VLSI architecture for CBAC decoding in AVS. Compared with CBAC in H.264/AVC, the simpler binarization methods and context selection schemes are adopted in AVS. In order to avoid the slow multiplications, the traditional arithmetic calculation is transformed to the logarithm domain. Although these features can obtain better balance between the compression gain and implementation cost, it still brings huge challenge for high-throughput implementation. The fact that current bin decoding depends on previous bin results in long latency and limits overall system performance. In this paper, we present a software–hardware co-design by using bin distribution feature. A novel pipeline-based architecture is proposed where the arithmetic decoding engine works in parallel with the context maintainer. A finite state machine (FSM) is used to control the decoding procedure flexibly and the context scheduling is organized carefully to minimize the access times of context RAMs. In addition, the critical path is optimized for the timing. The proposed implementation can work at 150 MHz and achieve the real-time AVS CBAC decoding for 1080i HDTV video. 相似文献
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Due to the growing demand of digital convergence, there is a need to have a video encoder/decoder (codec) that is capable of supporting multiple video standards on a single platform. High Efficiency Video Coding (HEVC), successor to H.264/MPEG-4 AVC, is a new standard under development that aims to substantially improve coding efficiency compared to AVC High Profile. This paper presents an efficient architecture based on a resource sharing strategy that can perform the quantization operation of the emerging HEVC encoder and six other video encoders: H.264/AVC, AVS, VC-1, MPEG-2, MPEG-4, and Motion JPEG (MJPEG). Since HEVC is still in the drafting stage, the proposed architecture is designed in such a way that any final changes can be accommodated into the design. The proposed quantizer architecture is completely division-free, as the division operation is replaced by shift and addition operations for all the codecs. The design is implemented on an FPGA and later synthesized in CMOS 0.18 μm technology. While working at 190 MHz, the design can decode a 1080p HD video at up to 61 frames per second. The multi-codec architecture is also suitable for low-cost VLSI implementation. 相似文献
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尽管音视频编码标准(Audio and Video Coding Standard,AVS)的编码性能可以与H.264相媲美,但是H.264的应用范围更加广泛,因此视频由AVS标准转码成H.264标准具有很大的应用前景.目前,主流的转码方法是将AVS的分块模式与H.264的分块模式映射的方式降低转码复杂度,但是技术之间的差异导致这两种标准之间的分块模式并不是一一映射的关系,因此会导致编码效率大幅度降低.提出一种基于改进KNN(K最邻近节点)算法的AVS到H.264/AVC快速转码方法.充分利用了AVS码流中的各种信息,通过改进的KNN算法建立了中间信息和H.264分块模式之间的映射模型.根据AVS中运动矢量信息的差异自适应确定H.264可能的分块模式,实验结果表明上述问题得到有效解决,该算法在保证H.264编码效率的前提下大幅降低了转码复杂度. 相似文献