Video Bitstream Research Articles

A video steganalytic algorithm against motion-vector-based steganography

Steganalysis is the art of detecting the information hidden in the media using steganography. In this paper, a steganalytic method is proposed to detect information hidden in the motion vectors of video bit-streams. Based on the statistical analysis of relative properties, the feature classification technique is adopted to determine the existence of hidden messages. The Support Vector Machine (SVM) is used as the discriminator. The experimental results show that the proposed method can detect the hidden data effectively in motion-vector-based steganography algorithms.

A solution to efficient power allocation for H.264/SVC video transmission over a realistic MIMO channel using precoder designs

In this paper we propose a novel scheme for real time SVC-based video transmission over MIMO channels in the context of Joint Source Channel Coding (JSCC). This scheme compares the transmission of the H.264/SVC video over four precoder solutions, namely Max-SNR, WF, QoS and E- d min . We exploit the high flexibility of the QoS precoder to minimize the total distortion of the received video. The proposed adaptive QoS precoder takes into account the scalability of the H.264/SVC standard jointly with the instantaneous MIMO channel statue. Finally, the proposed scheme is evaluated over both statistical and time varying realistic MIMO channels. This study provides the performance of these four precoder designs in term of BER, ML decoder complexity and the quality of the received video. We show that the precoder solutions providing the best BER performance are not usually the most appropriate for real time video transmission. However, the adaptive QoS precoder which uses three configurations, by considering both the importance of the video bitstream and the channel statue, provides the best Rate-Distortion performance regardless the channel conditions. We assess the accuracy of these four precoder solutions against channel estimation errors over time varying realistic MIMO channel. The results shows that the adaptive QoS precoder remains robust against channel estimation errors even at high mobility speed.

Semantic scalability using tennis videos as examples

With advances in broadcasting technologies, people are now able to watch videos on devices such as televisions, computers, and mobile phones. Scalable video provides video bitstreams of different size under different transmission bandwidths. In this paper, a semantic scalability scheme with four levels is proposed, and tennis videos are used as examples in experiments to test the scheme. Rather than detecting shot categories to determine suitable scaling options for Scalable Video Coding (SVC) as in previous studies, the proposed method analyzes a video, transmits video content according to semantic priority, and reintegrates the extracted contents in the receiver. The purpose of the lower bitstream size in the proposed method is to discard video content of low semantic importance instead of decreasing the video quality to reduce the video bitstream. The experimental results show that visual quality is still maintained in our method despite reducing the bitstream size. Further, in a user study, we show that evaluators identify the visual quality as more acceptable and the video information as clearer than those of SVC. Finally, we suggest that the proposed scalability scheme in the semantic domain, which provides a new dimension for scaling videos, can be extended to various video categories.

Efficient Spatial-Temporal Error Concealment Algorithm and Hardware Architecture Design for H.264/AVC

This paper presents an efficient error concealment algorithm for video bitstream over error-prone channel suffering from damage. Moreover, hardware architecture design and chip implementation of the proposed error concealment algorithm are also presented. For spatial error concealment, a mode selection algorithm considering the reuse of intra mode information embedded in bitstream is developed for the adaptation of bilinear and directional interpolation. It suffers only 0.08 dB video quality drop in average but the speedup measured on a general purpose processor is up to 40 times compared with the conventional methods. It is also more suitable for low cost hardware design. For temporal error concealment, the decoded motion vectors of the neighboring blocks of the corrupted macroblock are reused to provide hints to estimate the motion vector of the corrupted macroblock. Moreover, for real-time applications, a data and computational results reuse scheme of motion vector estimation is proposed and 96% computation and memory bandwidth can be reduced compared with the conventional methods with 0.18 dB quality drop in average. With the UMC 90 nm 1P9M process, the proposed error concealment engine can process HDTV1080P 30 frames per second video data and the power consumption is 15.77 mW at 125 MHz operation frequency.

Reduced complexity H.264/AVC transrating based on frequency selectivity for high-definition streams

In this paper, we present a complete transrating architecture for H.264/AVC high-definition video bitstreams. Based on frequency-selective filtering, this architecture has a minimized complexity and is drift-error-free for intra-coded pictures. Moreover, both Video Quality Metric (VQM) experiments and subjective analysis show that the algorithm gives satisfactory results in terms of visual quality. Our solution introduces blurring only compared to conventional requantization transrating, which also introduces other artifacts as distortion. We propose an easy and efficient bitrate estimation model controlled by transrating parameters.

Network-aware perceptual error concealment method for H.264 video with side information

In order to improve the video quality of transmission with data loss, a spatial and temporal error concealment method was proposed, which considered both the state information of the network and the perceptual weight of the video content. The proposed method dynamically changed the reliability weight of the neighboring macroblock, which was used to conceal the lost macroblocks according to the packet loss rate of the current channel state. The perceptual weight map was utilized as side information to do weighted pixel interpolation and side-match based motion compensation for spatial and temporal error concealment, respectively. And the perceptual weight of the neighboring macroblocks was adaptively modified according to the perceptual weight of the lost macroblocks. Compared with the method used in H.264 joint model, experiment results show that the proposed method performs well both in subjective video quality and objective video quality, and increases the average peak signal-to-noise ratio (PSNR) of the whole frame by about 0.4 dB when the video bitstreams are transmitted with packets loss.

No-Reference PSNR Identification of MPEG Video Using Spectral Regression and Reduced Model Polynomial Networks

This letter proposes a no-reference MacroBlock (MB) level PSNR identification of compressed MPEG video. Features are extracted on MB basis from video bitstreams and reconstructed images. The identification problem is formalized using reduced model polynomial networks. The letter proposes a two-step identification solution in which supervised spectral regression is used to reduce the dimensionality of the feature vector prior to model estimation. Two identification scenarios are presented in the experimental results, namely, video sequence dependent and video sequence independent identification. Based on the various video sequences used in the experiments, it is shown that the average mean absolute difference between the actual and the identified PSNRs is 1 dB and 1.6 dB for the sequence dependent and sequence independent identification respectively.

Scalable video delivery over MIMO OFDM wireless systems using joint power allocation and antenna selection

This paper proposes a scalable video delivery transmission framework over multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) wireless channels by combining power allocation and antenna selection schemes. The framework, which consists of independently decodable layers (3D ESCOT), an unequal error protection (UEP) channel coding structure, and an antenna selection scheme, provides more system error resilience even during periods of deep fading in wireless channels. A new algorithm is proposed to obtain the optimal power allocation and optimal transmission rate allocation among multiple layers, subject to constraints on the total transmission rate and the total power level. This proposed joint power allocation and antenna selection algorithm in MIMO OFDM systems enables us both to overcome the challenge of full channel state information (CSI) that was assumed to be necessary in the existing approaches and to utilize an estimated CSI from the receiver so as to achieve the optimal solution for a video bitstream in terms of its total expected distortion. Simulation results show that the proposed framework significantly improved system performance. Generally, as the wireless channel conditions change, the framework proposed can scale and transport the scaled video streams to receivers with smooth transitions in perceived quality.

Distortion optimal transmission of multi-layered FGS video over wireless channels

We analytically model the distortion of a scalable video bitstream containing a Base Layer (BL) and one or more Enhancement Layers (ELs). Utilizing our distortion model, we propose a pair of low complexity Unequal Error Protection (UEP) methods for transmitting BL and EL bitstreams over a wireless channel. Our one dimensional Forward Error Correction (FEC) UEP methods protect each bitstream against both temporally correlated bit errors caused by fading and packet erasures caused by network buffering. Our methods use optimal symbol interleaving to combat tandem loss effects. We illustrate the performance advantage of our methods over a baseline Equal Error Protection (EEP) and a number of UEP methods for different available budgets and channel conditions.

A reduced-reference structural similarity approximation for videos corrupted by channel errors

In this paper we propose a reduced-reference quality assessment algorithm which computes an approximation of the Structural SIMilarity (SSIM) metrics exploiting coding tools provided by the distributed source coding theory. The algorithm has been tested to evaluate the quality of decoded video bitstreams after transmission over error-prone networks. We evaluate the accuracy of the proposed quality assessment algorithm by measuring the Pearson’s correlation coefficient between the structural similarity metrics computed in full-reference mode and the one provided by the proposed reduced-reference algorithm. The proposed reduced-reference algorithm achieves good correlation values (higher than 0.85 with packet loss rate equal up to 2.5%).

Hardware design of motion data decoding process for H.264/AVC

In H.264/AVC, motion data can be basically derived by the following two schemes: one is a typical spatial prediction scheme based on the DPCM and the other is a sophisticated spatiotemporal prediction scheme for the skipped motion data, formally referred to as a direct mode. We verified through instruction level profiling that when these schemes are combined with various H.264/AVC coding techniques, the computational burden to derive the motion data could be considerably aggravated. Specifically, its computational complexity amounts to maximally 55% of that of the overall syntax parsing process. In this paper, we aim at an efficient hardware design of the motion data decoding process for H.264/AVC, for which all the key design considerations are addressed in detail and respective rational answers are presented. As comparing the resulting hardware design with the processor-based solution, its effectiveness was clearly demonstrated. The proposed design was implemented with 43.2 K logic gates and three on-chip memories of 3584 bits using Samsung Semiconductor’s Standard Cell Library in 65 nm L6LP process technology (SS65LP), and was capable of operating the H.264/AVC high-profile video bitstream of 1080p@60fps at 100 MHz consuming 843 μW.

Distortion-Minimized Video Slicing for Unequal Loss Protection

This letter proposes a distortion-minimized slicing scheme for the unequal loss protection of compressed video bitstreams transported over packet networks. Unlike most existing slicing methods where each slice includes nearly equal number of video macroblocks, the proposed scheme reorders the macroblocks in one video frame according to their importance, and then divides them into two slices with an unequal proportion. According to given channel conditions and a novel unequal loss protection scheme, the more appropriate macroblock division ratio can be found out to achieve minimized end-to-end distortion. Simulation results show that the proposed slicing scheme outperforms state-of-the-art approaches with fixed macroblock division ratio.

Complete Video Quality-Preserving Data Hiding

Although many data hiding methods are proposed in the literature, all of them distort the quality of the host content during data embedding. In this paper, we propose a novel data hiding method in the compressed video domain that completely preserves the image quality of the host video while embedding information into it. Information is embedded into a compressed video by simultaneously manipulating Mquant and quantized discrete cosine transform coefficients, which are the significant parts of MPEG and H.26x-based compression standards. To the best of our knowledge, this data hiding method is the first attempt of its kind. When fed into an ordinary video decoder, the modified video completely reconstructs the original video even compared at the bit-to-bit level. Our method is also reversible, where the embedded information could be removed to obtain the original video. A new data representation scheme called reverse zerorun length (RZL) is proposed to exploit the statistics of macroblock for achieving high embedding efficiency while trading off with payload. It is theoretically and experimentally verified that RZL outperforms matrix encoding in terms of payload and embedding efficiency for this particular data hiding method. The problem of video bitstream size increment caused by data embedding is also addressed, and two independent solutions are proposed to suppress this increment. Basic performance of this data hiding method is verified through experiments on various existing MPEG-1 encoded videos. In the best case scenario, an average increase of four bits in the video bitstream size is observed for every message bit embedded.

Scalable video coding over RTP and MPEG-2 transport stream in broadcast and IPTV channels

The ITU-T and ISO/IEC standard for scalable video coding was recently finalized. SVC allows for scalability of the video bitstream in the temporal, spatial, or fidelity domain, or any combination of those. Video scalability may be used for different purposes, such as saving bandwidth when the same media content is required to be sent simultaneously on a broadcast medium at different resolutions to support heterogeneous devices, when unequal error protection shall be used for coverage extension in wireless broadcasting, as well as for rate shaping in IPTV environments. Furthermore, it may also be useful in layered multicast transmission over the Internet or peer-to-peer networks, or in any transmission scenario where prioritized transmission for network flows is meaningful. In order to make usage of SVC in the aforementioned use cases, standards for defining the transport format and procedure are required. Therefore, we give a detailed overview of the recently finished SVC standards on transport over IP/RTP and the MPEG-2 transport stream. Both standards are important for IPTV and video on demand, where the first is important for SVC transport over mobile broadcast/multicast channels, and the latter is also important for SVC transport over traditional digital broadcast channels.

Scalable Video Streaming With Fine-Grain Adaptive Forward Error Correction

In this paper, we investigate a fine-grain adaptive forward error correction (FGA-FEC) coding scheme for scalable video bitstreams. In our work, both the embedded source bitstream and the error-control codes are granularly adapted at block level in intermediate overlay nodes to satisfy heterogeneous users with both different video frame-rate/spatial resolution/quality preferences and different network connections. The proposed FGA-FEC scheme encodes and adapts the embedded source-coded bitstream in such a way that if part of the video source data is actively dropped, parity bits protecting that piece of data are also removed, yielding an efficient result without any transcoding.

H.264-based watermarking for compressed video

Concerning the new features of the H.264/AVC video coding standard,a schema based on H.264 low bit-rate video stream was proposed.This paper improved the robustness and effectiveness of the traditional Differential Energy Watermarking(DEW) using the formula of energy distribution.The watermark extracting was carried out in the decode time and the original video was not needed during the process.The experimental results show that this schema can maintain a small change in bit-rate and keep small distortion,which means the proposed schema is effective.

A new bitstream random access scheme using multipicture motion-compensated prediction

Multipicture motion-compensated prediction is exploited to improve compression performance in the up-to-date video coding standards. However, in order to support random access into video bitstream, a restriction on multipicture motion-compensated prediction is introduced: the number of reference pictures has to be limited so that the pictures prior to random access point (RAP) are not allowed to be referenced by those predictive pictures following the RAP. This restriction leads to a decrease of coding efficiency. In this paper, a new kind of picture for reference, the recovery picture, is proposed to compensate the decrease of coding efficiency by taking full use of multipicture motion-compensated prediction. Furthermore, the proposed scheme supports random access without the assistance of the transmitting end. Some factors affecting the proposed schemeiquests performance are discussed. The experimental results show that the proposed random access scheme achieves better compression performance compared with the existing random access scheme.

A Temporal Approach for Improving Intra-Frame Concealment Performance in H.264/AVC

The highly error-prone nature of wireless environments and limited computational power of mobile devices necessitates the implementation of robust yet simple error concealment in H.264/AVC. In this paper, we propose to use data hiding to facilitate the error concealment on intra-coded frames that utilizes the temporal redundancy in a wireless video bitstream. At the encoder side, the motion vector of a macroblock (MB) is encoded and imperceptibly embedded into other MB within the same intra-frame. If an MB is found missing at the decoder, the embedded information will be retrieved from the corresponding MB for the recovery of the lost MB. In order to isolate erroneous MBs caused by packet loss, a block shuffling scheme is applied. It is shown that the proposed method is able to shift the computation burden from decoder to encoder, and reduce the computation complexity of conventional error concealment methods. In addition, due to the use of real motion vectors for temporal concealment, the proposed method provides improved picture quality over the reference methods in H.264/AVC.

Compressed-Domain Techniques for Error-Resilient Video Transcoding Using RPS

In video applications where video sequences are compressed and stored in a storage device for future delivery, the encoding process is typically carried out without enough prior knowledge about the channel characteristics of a network. Error-resilient transcoding plays an important role to provide an addition of resilience to the video data, where or whenever it is needed. Recently, a reference picture selection (RPS) scheme has been adopted in an error-resilient transcoder in order to reduce error effects for the already encoded video bitstream. In this approach, the transcoder learns through a feedback channel about the damaged parts of a previously coded frame and then decides to code the next P-frame not relative to the most recent, but to an older, reference picture, which is known to be error-free in the decoder. One straightforward approach of adopting RPS in error-resilient transcoding is to decode all the P-frames from the previously nearest I-frame to the current transmitted frame which is then re-encoded with a new reference frame; this can create undesirable complexity in the transcoder as well as introduce re-encoding errors. In this paper, some novel techniques are suggested for an effective implementation of RPS in the error-resilient transcoder with the minimum requirement on its complexity. All the proposed techniques will manipulate video data in the compressed domain such that the computational loading of the transcoder is greatly reduced. By utilizing these new compressed-domain techniques, we develop a new structure to handle various types of macroblocks in the transcoder which re-uses motion vectors and prediction errors from the encoded bitstream. Experimental results demonstrate that significant improvements in terms of transcoder complexity and quality of reconstructed video can be achieved by employing our compressed-domain techniques.

A cross-layer design framework for robust IPTV services over IEEE 802.16 networks

This paper introduces a cross-layer design framework for robust and efficient video multicasting over IEEE 802.16 (also known as WiMAX) networks in metropolitan areas. In the framework, multiple description coding (MDC) on scalable video bitstreams at the source for achieving multiresolution robustness is jointly designed with superposition coding (SCM) on multicast signals at the channel to overcome multiuser channel diversity in wireless multicast. The coded multicast signals under the proposed framework can cope with multiuser channel diversity and mitigate the impact due to short-term channel fluctuations, which are the two most challenging issues in achieving robust and efficient video multicasting in metropolitan areas. We formulate the proposed framework and analyze its video quality performance in terms of the total receivable/ recoverable bitstreams by a receiver. A heuristic methodology is developed for system parameter selection and performance optimization that can be applied to practical scenarios of video multicasting for IPTV services in WiMAX. Simulation is conducted based on actual standard video sequences to verify the proposed methodology on parameter selection and performance optimization. Performance gains of the proposed cross-layer design framework in the presence of fading channel diversity are demonstrated.