基于H.264/AVC的视频信息隐藏算法

在H.264/AVC的帧内预测环节,调制H.264/AVC编码中I帧4×4亮度块的帧内预测模式实现信息隐藏.这种调制基于该模式与待隐藏比特之间的映射规则进行.宿主4×4块的具体位置由各块自身特点结合密钥所指定的嵌入位置模板确定.信息的提取过程不需要原始视频内容,也不需完全解码,而只要对码流中的帧内预测模式进行解码即可.     

基于H.264/AVC标准的脆弱视频水印算法研究

针对H.264/AVC的编码特征,本文提出一种基于H.264/AVC低比特率视频流的脆弱水印算法,该算法在I帧的量化后的4 4DCT块中结合系数值的符号特性与奇偶性,首先用倒数第二位非零系数与水印值一起生成标志信息,然后根据标志信息的值,利用最后一位非零系数的符号特性,修改系数值的奇偶性,从而将水印嵌入到最后一位非零系数中。在解码端根据4 4DCT块中最后两位非零系数的奇偶性关系提取水印,检测时不需要原始视频的参与。该算法具有较小的码率变化,以及较强的脆弱性。     

基于H.264/AVC的音视频同步压缩方法

利用H.264/AVC标准中DCT系数的奇偶特性.在编码端将音频比特流嵌入到视频DCT系数中一起压缩传输,在解码端解出视频同时根据相应算法提取出音频信息,从而实现音视频的同步压缩.实验表明该方法在不增加数据量的前提下,可以无失真地还原出音频信号,对视频质量影响很小.     

基于H.264宏块内码率控制的隐写算法

在H.264/AVC视频编码标准框架下,提出一种基于H.264宏块内码率控制的视频隐写算法,根据CSF函数对DCT变换频率进行分类,判别DCT变换块的不敏感频率,并对DCT块进行分类,最后通过秘密信息比特位指导DCT块不敏感频率系数的舍弃和选取。实验中进行了隐写容量测试、信噪比损失测试和视频压缩码流大小测试。实验表明,该算法在损失信噪比较小的情况下能嵌入较多的信息,并能保持原视频编码器的压缩特性。     

一种基于H.264/AVC的视频可逆脆弱水印算法

结合H.264压缩编码标准的特性,该文提出一种新的基于H.264/AVC的视频可逆脆弱水印算法。算法先计算当前宏块预测残差块量化的离散余弦变换(DCT)系数的哈希值生成认证码,再把认证码作为水印信息嵌入到下一个相邻宏块活性最大的44块的最后一个非零量化DCT系数中。在解码端,通过比较认证码和提取的水印信息进行视频数据完整性的认证。实验结果表明,该算法对视频质量和码率的影响较小,并且能对认证通过的视频数据进行还原和对认证失败的视频I帧遭篡改区域进行有效的定位。     

基于H.264的容错技术

H.264编码标准的提出极大地推动了视频网络的传输和应用。其在保留以往视频编码标准的基础上引入了很多新技术,这些特点为H.264错误隐藏提出了新的挑战。本文重点介绍H.264/AVC提供的新的差错控制方法及错误隐藏技术。     

基于半脆弱水印的H.264/AVC视频流的内容级认证

针对低码率的H.264/AVC视频流,提出了一种基于半脆弱水印的内容级视频认证方案.利用I帧内块组之间能量不变的特点构建基于内容的特征码,并根据DCT系数特点,通过符号编码方式嵌入到幅值较小的DCT系数.为了保持嵌入前后视频流码率的基本恒定,引入了误差准则函数.此外,根据P帧中低频AC系数的正负符号统计特性,将帧号嵌入到AC系数.通过对提取出的水印信息和重构的认证码进行比较可实现篡改检测.仿真实验结果验证了本方案的有效性.     

一种嵌入H.264/AVC的镜头切变检测算法

提出一种嵌入H.264/AVC的视频镜头切变检测算法,利用视频压缩过程中运动估计与补偿的结果,提高了检测的效率,大大降低了检测的运算量;同时,为了针对镜头内可能出现的噪声帧,利用H.264/AVC标准中的多参考帧特性,进一步提出了镜头内噪声帧或噪声序列段的检测窗口算法.     

基于H.264帧内预测模式的信息隐藏算法

根据H.264标准编码的特点,提出一种较高性能的信息隐藏方案。文章分析H.264中I4×4亮度块的9种帧内预测模式,以及最优模式的选择策略,将I4×4亮度块的9种帧内预测模式作为备选宿主,利用信息嵌入算法将信息嵌入到视频中。这样降低了信息隐藏过程中预测模式调整对视频质量的影响,并能提高嵌入信息数据量。     

一种基于H.264/AVC压缩域的GOP级视频场景转换检测算法

本文提出了一种基于H.264/AVC压缩域的GOP(Group of Pictures)级视频场景转换检测算法.该算法利用H.264/AVC基本档次码流中的帧内预测模式、运动矢量和宏块编码类型等可用信息,提出了基于子块的色度模式差异、累积运动值和累积帧内宏块数等三个判决准则,然后综合利用这三个判决准则,提出了一种GOP级的视频场景转换检测算法.实验结果表明,与现有的一个COP级场景检测算法对比,本文提出的GOP级视频场景转换检测算法可以获得更好的检测性能.     

Efficient information hiding in H.264/AVC video coding

This paper proposes a new real-time information hiding algorithm on latest H.264/AVC video coding standard. The information is embedded into the Trailing Ones of 4×4 blocks during the Context-based Adaptive Variable Length Coding (CAVLC) process. This algorithm is efficient with low computational complexity. The simulation results show that the degradation of video quality is negligible, and the same overall bit-stream length is maintained. Based on this information hiding method, a video subtitle transmission scheme is proposed. Under the simulation of different RTP packet loss channels, the embedded information can be well recovered. The comparison with other algorithms shows the superiority of our proposed method.     

A DCT/DST-based error propagation-free data hiding algorithm for HEVC intra-coded frames

Currently, two error propagation-free discrete cosine transform (DCT)-based data hiding algorithms, one by Ma et al. and the other by Lin et al., were presented for H.264/AVC intra-coded frames. However, the state-of-the-art video codec, high efficiency video coding (HEVC), adopts both integer DCT and discrete sine transform (DST) such that the previous DCT-based algorithms cannot fully utilize available capacity for data hiding in HEVC. This paper presents the first DCT/DST-based data hiding algorithm for HEVC intra-coded frames where the block DCT and DST coefficient characteristics are investigated to locate the transformed coefficients that can be perturbed without propagating errors to neighboring blocks. Experimental results confirm the merits of the proposed algorithm in providing the intra-frame error propagation-free advantage, the quality improvement for marked images, the compression power inherited from HEVC, and the superiority of embedding capacity for low bitrate coding when compared with the previous two algorithms for H.264/AVC.     

基于帧内预测模式的H.264/AVC视频信息嵌入算法

提出了一种基于帧内预测模式的H.264/AVC视频信息嵌入算法.在秘密信息进行嵌入时,根据人类视觉特性的掩蔽效应,筛选出I帧中纹理密集区域的4×4亮度块,确定为嵌入块.通过秘密信息调制4×4亮度块的预测模式最低有效位,完成秘密信息的嵌入.通过对算法进行仿真实验,证明本算法计算量小,能够实时处理.对视频载体影响小,有一定的嵌入容量,能够保证秘密信息的有效传输.     

A Very High Throughput Deblocking Filter for H.264/AVC

This paper presents a novel hardware architecture for the real-time high-throughput implementation of the adaptive deblocking filtering process specified by the H.264/AVC video coding standard. A parallel filtering order of six units is proposed according to the H.264/AVC standard. With a parallel filtering order (fully compliant with H.264/AVC) and a dedicated data arrangement in local memory banks, the proposed architecture can process filtering operations for one macroblock with less filtering cycles than previously proposed approaches. Whereas, filtering efficiency is improved due to a novel computation scheduling and a dedicated architecture composed of six filtering cores. It can be used either into the decoder or the encoder as a hardware accelerator for the processor or can be embedded into a full-hardware codec. This developed Intellectual Property block-based on the proposed architecture supports multiple and high definition processing flows in real time. While working at clock frequency of 150 MHz, synthesized under 65 nm low power and low voltage CMOS standard cell technology, it easily meets the throughput requirements for 4 k video at 30 fps of all the levels in H.264/AVC video coding standard and consumes 25.08 Kgates.     

General Architecture for MPEG-2/H.263/H.264/AVC to H.264/AVC Intra Frame Transcoding

The latest international video-coding standard H.264/AVC significantly achieves better coding performance compared to prior video coding standards such as MPEG-2 and H.263, which have been widely used in today’s digital video applications. To provide the interoperability between different coding standards, this paper proposes an efficient architecture for MPEG-2/H.263/H.264/AVC to H.264/AVC intra frame transcoding, using the original information such as discrete cosine transform (DCT) coefficients and coded mode type. Low-frequency components of DCT coefficients and a novel rate distortion cost function are used to select a set of candidate modes for rate distortion optimization (RDO) decision. For H.263 and H.264/AVC, a mode refinement scheme is utilized to eliminate unlikely modes before RDO mode decision, based on coded mode information. The experimental results, conducted on JM12.2 with fast C8MB mode decision, reveal that average 58%, 59% and 60% of computation (re-encoding) time can be saved for MPEG-2, H.263, H.264/AVC to H.264/AVC intra frame transcodings respectively, while preserving good coding performance when compared with complex cascaded pixel domain transcoding (CCPDT); or average 88% (a speed up factor of 8) when compared with CCPDT without considering fast C8MB. The proposed algorithm for H.264/AVC homogeneous transcoding is also compared to the simple cascaded pixel domain transcoding (with original mode reuse). The results of this comparison indicate that the proposed algorithm significantly outperforms the mode reuse algorithm in coding performance, with only slightly higher computation.     

Mode-Dependent Templates and Scan Order for H.264/AVC-Based Intra Lossless Coding

In H.264/advanced video coding (AVC), lossless coding and lossy coding share the same entropy coding module. However, the entropy coders in the H.264/AVC standard were original designed for lossy video coding and do not yield adequate performance for lossless video coding. In this paper, we analyze the problem with the current lossless coding scheme and propose a mode-dependent template (MD-template) based method for intra lossless coding. By exploring the statistical redundancy of the prediction residual in the H.264/AVC intra prediction modes, more zero coefficients are generated. By designing a new scan order for each MD-template, the scanned coefficients sequence fits the H.264/AVC entropy coders better. A fast implementation algorithm is also designed. With little computation increase, experimental results confirm that the proposed fast algorithm achieves about 7.2% bit saving compared with the current H.264/AVC fidelity range extensions high profile.     

基于纹理特征的H.264/AVC顽健视频水印算法

在分析现有视频水印算法的基础上,结合H.264压缩编码标准的特性,提出了一种新的基于纹理特征的视频顽健水印算法。算法先对当前帧4×4块进行整数离散余弦变换,判断其是否是纹理块,再采用能量差的方式自适应选择系数嵌入水印。实验结果表明,该算法对视频质量和码率的影响较小,并且能有效抵抗高斯噪声、低通滤波、重编码等常见的视频水印攻击。     

A novel watermarking scheme for H.264/AVC video authentication

As the H.264/AVC-based video products become more and more popular, issues of copyright protection and authentication that are appropriate for this standard will be very important. In this paper, a content-based authentication watermarking scheme for H.264/AVC video is proposed. Considering the new feature of H.264/AVC, the content-based authentication code for spatial tampering is firstly generated using the reliable features extracted from video frame blocks. The authentication code, which can detect malicious manipulations but allow recompression, is embedded into the DCT coefficients in diagonal positions using a novel modulation method. Spatial tampering can be located by comparing the extracted and the original feature-based watermarks. In addition, combining ECC and interleaving coding, the frame index of each video frame is used as watermark information and embedded in the residual coefficients. Temporal tampering can be detected by the mismatch between the extracted and the observed frame index. Experimental results show that the proposed scheme can discriminate the malicious tampering from the mild signal processing. The tampered location can also be approximately determined according to the glide window and the predefined threshold.     

融合宏块平坦度和时空相关性的预测模式选择算法

H.264/AVC以巨大编码复杂度为代价,在获得更高压缩率的同时,编码实时性也随之降低。针对视频编码中重要且耗时的帧间预测技术,分析了宏块平坦度和时空相关性,提出了一种快速的预测模式选择算法。仿真实验结果表明,本文提出算法与H.264/AVC(JM12.2)标准算法相比,在保持重建视频图像质量和输出码流结构的前提下,平均节省约70%的编码时间,并继承了H.264/AVC低码率的编码优势。     

An improved reversible data hiding-based approach for intra-frame error concealment in H.264/AVC

As H.264/AVC video streams are highly compressed, they become sensitive to errors caused by unreliable transmission channels. In order to address this issue, an improved version of Chung et al.’s reversible data hiding-based approach for intra-frame error concealment is proposed for H.264/AVC codec. By using the histogram shifting technique, the original work reversibly embeds the motion vector (MV) of a macroblock (MB) into other MB within the same intra-frame. If an MB is corrupted at the decoder side, the embedded MV can be extracted from the corresponding MB for the recovery of the corrupted MB. However, Chung et al.’s work did not fully exploit the number of coefficients which need to be modified in order to reversibly hiding data, and did not consider many extra nonzero residual blocks produced by data hiding. These two issues could reduce the visual quality of the stego-video. This paper adopts MV data pre-processing, the selection of most suitable embedding region, and the minimum possible amount of histogram modification, which lead to higher PSNR of the stego-video for a given payload. Experimental results further reveal that the proposed method offers stego-video with better visual quality over Chung et al.’s work.