基于H.264 的混沌视频加密系统

为了解决视频信息的安全问题,提出了一种基于视频编码标准H．264／AVC的混沌视频加密算法。利用流密码加密简单、运算速度快等优点,采用Logistic离散混沌序列对H．264／AVC标准的CAVLC（基于上下文的自适应变长编码）熵编码阶段的码流进行加密,并从算法的安全性、加密效率等方面进行分析。试验结果表明：该加密算法在保证视频内容信息安全性的前提下,不改变码流的结构,具有良好的实时性和快速性。     

新视频压缩标准H.264/AVC的研究

H.264/AVC是由ITU T视频编码专家组和ISO/IEC运动图像专家组成立的联合视频专家组制定的最新视频编码标准。H.264/AVC标准的主要目标是增强压缩性能,并提供“网络友好”的视频表达。概述了H.264的特点及应用,并详细介绍了H.264/AVC的核心技术。     

A practical design of content protection for H.264/AVC compressed videos by selective encryption and fingerprinting

Digital Rights Management (DRM) of videos is an important issue nowadays. Considering that H.264/AVC videos will be widely used in various applications, we propose a practical design, which combines the methodologies of selective encryption and fingerprinting, for effective DRM of H.264/AVC streaming videos. A selective encryption scheme is first presented to scramble the video content by encrypting a small amount of data in the compressed bit-stream. The scrambled video is H.264-compliant to reduce the complexity of decoder since it can still be played without triggering errors in the decoding process. A fingerprinting scheme is then introduced to provide further protection. We extract a reasonable amount of data from the video and embed the watermark acting as the fingerprint of the video recipient. To acquire the high-quality video for viewing, the user has to decrypt the video obtained from a video server and then combine it with the watermarked data provided from a user information server. The resulting viewable video is thus fingerprinted to deter the user from illegally redistributing the content. Experimental results will demonstrate the feasibility of the proposed approach.     

Fast intra coding algorithm for HEVC based on depth range prediction and mode reduction

Multimedia Tools and Applications - The latest High Efficiency Video Coding (HEVC) standard only requires 50% bitrate of the H.264/AVC at the same video quality. Due to introduction of more...     

A selective encryption scheme for protecting H.264/AVC video in multimedia social network

Aiming to protect H.264/AVC video in multimedia social network, a selective encryption scheme is put forward. In the scheme, after analyzing the impact of quantization parameter (QP) on the encryption of the sign of T1 s and the impact of encrypting inter-macroblock non-zero coefficients, the sign of intra-macroblock non-zero DCT coefficients, the sign of trailing ones (T1 s), the intra prediction modes (IPMs) and the sign of motion vector difference (MVD) are encrypted to protect the texture and motion information of H.264/AVC. Experimental results and analysis show that the computation cost is low and the bitrate increment is negligible, and it can achieve good performance in resisting brute-force attacks, histogram-based attacks and replacement attacks. Based on the encryption scheme, a framework of its implementation in multimedia social network is put forward. It has great potential to be implemented for the video data protection in multimedia social network.     

HEVC optimization based on human perception for real-time environments

High-Efficiency Video Coding (HEVC) is the new emerging video coding standard of the ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC Moving Picture Experts Group (MPEG). The HEVC standard provides a significant improvement in compression efficiency in comparison with existing standards such as H264/AVC by means of greater complexity. In this paper we will examine several HEVC optimizations based on image analysis to reduce its huge CPU, resource and memory expensive encoding process. The proposed algorithms optimize the HEVC quad-tree partitioning procedure, intra/inter prediction and mode decision by means of H264-based methods and spatial and temporal homogeneity analysis which is directly applied to the original video. The validation process of these approaches was conducted by taking into account the human visual system (HVS). The adopted solution makes it possible to perform HEVC real time encoding for HD sequences on a low cost processor with negligible quality loss. Moreover, the frames pre-processing leverages the logic units and embedded hardware available on an Intel GPU, so the execution time of these stages are negligible for the encoding processor.

     

Real-time H.264/AVC baseline decoder implementation on TMS320C6416

The H.264/AVC Advanced Video Coding standard (AVC) is poised to enable a wide range of applications. However, its increased complexity creates a big challenge for efficient software implementations. This work develops and optimises the H.264/AVC video decoder level two on the TMS320C6416 Digital Signal Processor (DSP) for video conference applications. In order to accelerate the decoding speed, several algorithmic optimisations have been ported to inverse entropy decoding and intra-prediction modules. The parallelism between algorithm execution and data transfers was fully exploited using Enhanced Direct Memory Access (EDMA) engine. Furthermore, based on the DSP architectural features, various core-specific optimisation techniques were adopted leading to an increase in speed by up to 70%. Intensive experimental tests prove that a real-time decoding on TMS320C6416 DSP running at 720?MHz is obtained for Common Intermediate Format resolution (CIF 352?×?288).     

基于H.264视频编码的自适应去块滤波系统

介绍了H.264视频编码标准中的自适应去块滤波系统,分析了该系统原理及其相对于以往去块效应滤波系统的改进。并通过仿真试验验证了在提高图像质量和降低视频流码率上有较好的效果。     

基于H．264视频编码的自适应去块滤波系统

介绍了H.264视频编码标准中的自适应去块滤波系统，分析了该系统原理及其相时于以往去块效应滤波系统的改进。并通过仿真试验验证了在提高图像质量和降低视频流码率上有较好的效果。     

Reversible video data hiding using zero QDCT coefficient-pairs

Multimedia Tools and Applications - H.264/Advanced Video Coding (AVC) is one of the most commonly used video compression standard currently. In this paper, we propose a Reversible Data Hiding (RDH)...     

Chaos-based selective encryption for H.264/AVC

Encryption techniques are usually employed to maintain the secrecy of the video streams transmitted via a public network. However, full encryption using strong cryptographic algorithms is usually not necessary if the purpose is to destroy the commercial value by preventing pleasant viewing. For this purpose, selective encryption is preferred as its operating efficiency is higher. Here, a chaos-based selective encryption scheme implemented on the H.264/AVC standard is proposed. The scheme employs multiple Rényi chaotic maps to generate a pseudorandom bit sequence which is used to mask the selected H.264/AVC syntax elements. It provides sufficient protection against full reconstruction while keeping the format compliance property so as not to cause decoding error without the key. The operating efficiency is high due to the low computational complexity of the Rényi chaotic map, as justified by the simulation results using video clips at various resolutions. Moreover, the security analyses show that the proposed algorithm is highly sensitive to the secret key and possesses good perceptual security.     

DCLSA：一种适用于H.264/AVC的DCT系数分层置乱算法

基于目前的DCT系数加密算法在安全性、压缩比和信噪比上都各自存在缺点,提出了一种新的适用于H264/AVC的DCT系数分层置乱算法(DCLSA)。该算法针对H264/AVC中4×4 DCT变换的特点,首先将同一宏块中每个4×4块DCT系数进行块间分层,构建系数分层模型,然后可根据安全性要求对不同层系数进行随机置乱,实现加密编码。通过性能比较和具体实验效果分析,此算法具有更高的安全性、更优的压缩比和较好的信噪比,适合于H.264/AVC的网络安全应用。     

A fast inter-frame encoding scheme using the edge information and the spatiotemporal encoding parameters for HEVC

Multimedia Tools and Applications - High Efficiency Video Coding (HEVC), as a novel video coding standard, has shown a better coding efficiency than all existing standards, such as H.264/AVC. It...     

A reduced reference video quality assessment of H.264 and mpeg2 codec based on sharpness metric

In this paper, we propose a new perceptually significant video quality metric for the H.264/Motion Picture Expert Group (MPEG)‐4 Advanced Video Coding (AVC) and MPEG2 standard. Our method operates in the spatial domain by using the Sobel filter. The proposed approach does not require a high computational complexity and can be suitable for real‐time evaluation. We evaluate the performance of the proposed method by using three Common Intermediate Format sequences at different compression rates. The comparison of the obtained results is made with some video quality models using “LIVE”, “IVP” and “IRCCyN/IVC 1080i” databases. The performance metrics, i.e. Pearson and Spearman correlation coefficients, indicate that the proposed method gives a good performance in H264 and MPEG2 codec distortions with the three databases comparing with other models.     

Effective algorithms for fast transcoding of AVS to H.264/AVC in the spatial domain

This paper proposes a transcoding scheme from AVS to H.264/AVC. As high-compression video coding standards, H.264/AVC jointly developed by MPEG and ITU and AVS developed by the Audio Video Coding Standard Working Group of China will co-exist in the future market. Therefore, it is worthy to transcode the AVS format to the H.264/AVC format or vice versa. After an insight into the inter transcoding from AVS to H.264/AVC, a simple and effective method is proposed by reusing the mode and motion vectors to achieve high-efficient and fast transcoding. The problem in reusing the skip mode is studied and an effective method to eliminate the artifacts is proposed. Furthermore, a fast intra transcoding algorithm based on the distribution of the DCT coefficients is proposed to speed up the transcoding process. Detailed experiment results demonstrate that the proposed algorithm can effectively reduce the transcoding complexity.

Performance analysis of hybrid coders in multi-constraints pruned environment

Multimedia Tools and Applications - Advance Video Coder (H.264/AVC) and High-Efficiency Video (H.265/HEVC) coders are fast developing video compression standards, provides high compression and...     

Fast multiframe motion estimation algorithms by motion vector composition for the MPEG-4/AVC/H.264 standard

The MPEG-4/AVC/H.264 video coding standard adopts various coding schemes such as multiple reference frames and variable block sizes for motion estimation. Hence, MPEG-4/AVC/H.264 provides gains in compression efficiency of up to 50% over a wide range of bit rates and video resolutions compared to previous standards. However, these features result in a considerable increase in encoder complexity, mainly regarding to mode decision and motion estimation. The proposed algorithms use the stored motion vectors to compose the motion vector without performing the full search in each reference frame. Therefore, the proposed algorithms can obtain an average speed up ratio of four for encoding, thus benefiting from the prediction of the motion vector for the reference frames in advance and maintaining good performance. Any fast search algorithm can be utilized to further largely reduce the computational load.     

H.264/AVC的特点及其在视频监控中的应用

H．264／AVC是视频编码专家组(VCEG)和活动图像专家组(MPEG)联合制定的新的视频编码标准,其目的就是解决以往标准暴露出来的缺点。文章首先指出目前采用其他标准设计视频监控系统的不足,分析了H．264／AVC视频编码标准的特点,指出H．264／AVC适于视频监控应用的优势所在,最后重点阐述了H．264／AVC标准中分层编码技术和SP／SI帧技术在视频监控中的应用。     

H.264/AVC先进视频编码研究

为了取得更高的图像压缩性能和更多的实用功能,ISO／IEC MPEG(运动图像专家组)和ITU-TVCEG(视频编码专家组)共同制订了一套新的视频编码标准H．264／AVC。介绍了H．264／AVC图像编解码系统的实现过程,对其采用的新技术进行了描述,最后将其与H．263和MPEG-4标准进行了性能对比。     

Fast HEVC I-frame coding based on strength of dominant direction of CUs

High efficiency video coding (HEVC), the latest international video coding standard, greatly outperforms previous standards such as H.264/AVC in terms of coding bitrate and video quality. The coding efficiency improvement in HEVC is achieved by introducing several new techniques such as recursive quad-tree structure and increased number of intra prediction modes. However, computational load is also increased due to employing the new techniques. In this paper, we propose a solution for fast I-frame coding in HEVC standard using homogeneity of Coding Units (CUs). The proposed solution consists of two stages. In the first stage, we evaluate CU homogeneity by computing a parameter named dominant direction strength and predict CU size by this means. In the second stage, we select 11 modes out of 35 for the specified CU size based on dominant direction of the CU. Experimental results indicate that the proposed method achieves on average 45.8 % reduction on coding time, with very similar coding efficiency as the HEVC reference software. Moreover, we designed tree-stage pipelined architecture for our method which can operate at 235 MHz maximum clock rate which means it can be used for real-time coding of all intra configuration of HEVC videos up to level 6.2.