共查询到16条相似文献,搜索用时 109 毫秒
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视频通信时通常带宽有限,为了能在规定的目标码率下获得尽可能高质量的解码图像,需要在视频编码时进行码率控制.目前针对HEVC的并行编码以及对应码率控制已成为研究热点,现有并行结构下的平均比特率控制算法受到帧间依赖性的约束,待编码帧无法及时获得与其并行编码帧的实际比特数,因此本文算法通过预测并行帧的实际比特数来进行码率控制,并在此基础提出了自适应调整帧层量化参数补偿值.仿真结果表明,相比已有算法,前者减少码率误差约为3.38%,后者可提高PSNR约为0.204 dB同时减少约0.3%的码率误差. 相似文献
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随着分层B帧码率控制技术在SVC(可伸缩视频编码)中的广泛应用,视频编码的质量得到了很大提高,然而传统的H.264码率控制技术并未将B帧的比特分配考虑在内。提出一种基于分层B帧架构自适应调节B帧比特分配的码率控制算法,该算法研究了基于同一个图像组(GoP)中各时域层权重因子的自适应调节,为各时域层分配不同的目标比特;同时基于同一个时域层中各帧复杂度的不同,为各帧分配不同的目标比特。实验结果表明,与目前流行的分层B帧码率控制算法相比,该算法在比特控制误差并未降低的情况下,客观质量PSNR可提高0.1~0.4 dB。 相似文献
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针对分级B帧编码结构,提出了一种基于比特分配线性模型的码率控制算法.通过实验发现不同时间级B帧平均比特数与P帧比特数呈良好的线性关系,利用此线性关系对B帧进行比特分配可以充分利用不同时间级B帧的特性,提高分级B帧结构码率控制的性能.实验结果表明,该算法与JVT-W042相比,对于大部分内容特性序列,平均△SNR提高0.15 dB以上. 相似文献
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针对分级B帧编码结构,提出了一种基于比特分配线性模型的码率控制算法。通过实验发现不同时间级B帧平均比特数与P帧比特数呈良好的线性关系,利用此线性关系对B帧进行比特分配可以充分利用不同时间级B帧的特性,提高分级B帧结构码率控制的性能。实验结果表明,该算法与JVT-W042相比,对于大部分内容特性序列,平均ΔPSNR提高0.15 dB以上。 相似文献
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本文提出了一种低计算复杂度的VBR码率控制算法,它不需要对视频序列进行预先分析或多次编码.该算法的主要思想是根据压缩码流统计信息,建立码率-失真模型,计算目标比特开销,然后通过一个反馈机制在帧层调节量化因子,使得目标比特预算满足缓冲区约束条件,并尽可能地维持量化因子的稳定.仿真结果表明,本文提出的方法不仅能够保证总体比特预算和缓冲区约束,获得相对稳定的视频质量,特别是对场景切换也有很强的适应性,而且实现简单,运算复杂度低,可应用于实时视频编码. 相似文献
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Wyner-Ziv视频编码中无反馈速率控制算法研究 总被引:1,自引:0,他引:1
为了避免在分布式视频编码系统中使用反馈信道,提出了一种基于Wyner-Ziv编码的无反馈速率控制算法。首先,利用目标码率和目标帧率进行GOP层码率分配;然后,根据原始图像的帧间相关性动态选择量化因子和量化矩阵来分配每个GOP内关键帧和Wyner-Ziv帧的比特数;接下来,利用系数带级的相关性计算相关噪声模型参数,并选择对应的LDPC校验矩阵,提出Wyner-Ziv帧的无反馈比特面速率控制算法。实验结果表明,在给定目标码率下,所提算法的编码码率误差小于0.57%,且与现有无反馈速率控制算法相比,解码恢复图像的PSNR(峰值信噪比)可以提高1dB。另外,该算法基本没有增加编码端复杂度,可用于实际分布式视频通信系统。 相似文献
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多视点纹理加深度编码的联合码率控制方法 总被引:1,自引:0,他引:1
码率控制技术是多视点视频编码和传输中一个关键的问题。为了提高三维(3D)视频的整体显示质量,包括虚拟视点质量和编码视点质量,提出一种多视点纹理加深度编码的联合码率控制方法。该算法研究了纹理和深度的关系,采用基于模型方法确定最优的纹理和深度之间的码率比例。根据各个视点编码结果的统计规律,不同的视频序列采用不同的视点间比特分配比例。实验结果表明,与目前流行的多视点码率控制算法相比,该算法在计算复杂度基本保持不变的情况下,平均码率控制误差在0.6%以内,客观质量PSNR最高可提高0.65 dB。 相似文献
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In order to further improve the efficiency of video compression, we introduce a perceptual characteristics of Human Visual System (HVS) to video coding, and propose a novel video coding rate control algorithm based on human visual saliency model in H.264/AVC. Firstly, we modifie Itti's saliency model. Secondly, target bits of each frame are allocated through the correlation of saliency region between the current and previous frame, and the complexity of each MB is modified through the saliency value and its... 相似文献
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RATE CONTROL ALGORITHM FOR H.264 VIDEO ENCODER 总被引:1,自引:0,他引:1
Xue Jinzhu Shen Lansun 《电子科学学刊(英文版)》2003,20(6):456-460
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1 IntroductionThelow delayrateisanimportantrequirementofvideoencodinginreal timeapplicationssuchasvideophoneandvideoconferencing .Theratecon trolofTMN5[1 ] iswellknownintheH .2 63encon der,butitcannotgivesatisfactory performanceinlowbit ratevideocoing .Whentheen… 相似文献
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Marleen Morbee Antoni Roca Josep Prades-Nebot Aleksandra Pižurica Wilfried Philips 《Signal, Image and Video Processing》2008,2(2):129-140
In some video coding applications, it is desirable to reduce the complexity of the video encoder at the expense of a more
complex decoder. Wyner–Ziv (WZ) video coding is a new paradigm that aims to achieve this. To allocate a proper number of bits
to each frame, most WZ video coding algorithms use a feedback channel, which allows the decoder to request additional bits
when needed. However, due to these multiple bit requests, the complexity and the latency of WZ video decoders increase massively.
To overcome these problems, in this paper we propose a rate allocation (RA) algorithm for pixel-domain WZ video coders. This
algorithm estimates at the encoder the number of bits needed for the decoding of every frame while still keeping the encoder
complexity low. Experimental results show that, by using our RA algorithm, the number of bit requests over the feedback channel—and
hence, the decoder complexity and the latency—are significantly reduced. Meanwhile, a very near-to-optimal rate-distortion
performance is maintained.
This work has been partially supported by the Spanish Ministry of Education and Science and the European Commission (FEDER)
under grant TEC2005-07751-C02-01.
A. Pižurica is a postdoctoral research fellow of FWO, Flanders. 相似文献
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Long Xu Sam Kwong Hanli Wang Debin Zhao Wen Gao 《Signal Processing: Image Communication》2013,28(1):20-33
In this paper, a novel rate control scheme with sliding window basic unit is proposed to achieve consistent or smooth visual quality for H.264/AVC based video streaming. A sliding window consists of a group of successive frames and moves forward by one frame each time. To make the sliding window scheme possible for real-time video streaming, the initial encoder delay inherently in a video streaming system is utilized to generate all the bits of a window in advance, so that these bits for transmission are ready before their due time. The use of initial encoder delay does not introduce any additional delay in video streaming but benefits visual quality as compared to traditional one-pass rate control algorithms of H.264/AVC. Then, a Sliding Window Buffer Checking (SWBC) algorithm is proposed for buffer control at sliding window level and it accords with traditional buffer measurement of H.264/AVC. Extensive experimental results exhibit that higher coding performance, consistent visual quality and compliant buffer constraint can be achieved by the proposed algorithm. 相似文献