Video Compression Algorithms Research Articles

Residue data prediction algorithm for efficient video compression

A novel residue data prediction algorithm to improve video coding efficiency is presented. The proposed algorithm performs an additional second prediction to remove the remaining signal correlation after the first prediction. Simulation results show that the proposed algorithm can reduce bit rate by up to 8.01% compared with the JM reference software without any degradation of the peak-signal-to-noise ratio.

A Novel Prediction-Based Directional Asymmetric Search Algorithm for Fast Block-Matching Motion Estimation

This paper proposes a very fast block-matching motion estimation algorithm for video compression. This method uses a new concept involving a very compact center-biased characteristic in developing directional asymmetric search patterns, which we refer to as directional asymmetric search (DAS). The initial pattern of the DAS is a compact cross pattern containing only five initial search points. The DAS utilizes error information (block distortions) of the search patterns to determine the search direction, and then asymmetric search patterns are used in the subsequent steps accordingly. Furthermore, a prediction scheme and a best match prejudgment scheme are incorporated to favor fast motion and to benefit stationary and quasi-stationary blocks, respectively. Therefore, the proposed method significantly reduces the number of search points for locating a motion vector. Compared to conventional fast algorithms, the proposed method has the fastest search speed and most satisfactory PSNR values for all test sequences.

An Efficient Mode Selection Prior to the Actual Encoding for H.264/AVC Encoder

Many video compression algorithms require decisions to be made to select between different coding modes. In the case of H.264, this includes decisions about whether or not motion compensation is used, and the block size to be used for motion compensation. It has been proposed that constrained optimization techniques, such as the method of Lagrange multipliers, can be used to trade off between the quality of the compressed video and the bit rate generated. In this paper, we show that in many cases of practical interest, very similar results can be achieved with much simpler optimizations. Mode selection by simply minimizing the distortion with motion vectors and header information produces very similar performance to the full constrained optimization, while it reduces the mode selection and over all encoding time by 31% and 12%, respectively. The proposed approach can be applied together with fast motion search algorithms and the mode filtering algorithms for further speed up.

A Pilot Study of Video Compression Techniques for Stereoscopic Telepresence Applications

This paper focuses on evaluating and quantifying the effects of a novel foveated stereo video compression algorithm for visual telepresence applications. In a typical telepresence application, a user at the local site views real-time stereo video captured and transmitted from a telerobotic camera platform located at a remote site. The telerobotic camera platform tracks the user's head motion, producing the sensation of being present at the remote site. Three valuable factors were examined: foveation, disparity compression, and global motion compensation. The algorithm was analyzed by introducing the above-mentioned components separately. It was found that each component increased the compression rate significantly.

English

Lossless image compression has long been recognised as an important need for several applications such as medical imaging, storage of critical IR image sequences, and remote sensing. In this paper, a simple, fast and easy to realisable-on-hardware lossless video compression algorithm is proposed that is well-suited for IR imageries. Context-based median predictor is used for prediction of reference pixels. Three neighboring pixels are used as context for prediction. Inter-frame coding is performed by encoding the redundant pixels in an efficient way, using 1-bit code. Finally, the arithmetic coder is used as entropy coding. The proposed algorithm is able to operate in image compression and video compression mode. The proposed Median Predictor based Lossless Video Compression (MPLVC) algorithm is compared with Joint Pictures Experts Group-Lossless (JPEG-LS) and Fast and Efficient Lossless Image Compression System (FELICS) for compression performance. The results demonstrate that proposed algorithm is superior in encoding rate with added advantage in simplicity and ease in realization on hardware.Defence Science Journal, 2009, 59(2), pp.183-188, DOI:http://dx.doi.org/10.14429/dsj.59.1507

Hyperspectral image compression using a three-dimensional embedded zeroblock coding algorithm

Motion-compensated three-dimensional embedded zeroblock coding (MC 3-D EZBC) is a successful state-of-the-art video compression algorithm. We propose a hyperspectral image compression coder based on the 3-D EZBC algorithm without motion compensation. This coder adopts the 3-D wavelet transform to decorrelate and the 3-D EZBC algorithm without motion compensation to process bitplane zeroblock coding. For achieving good coding performance, the diverse 3-D wavelet transform structures and the several wavelet filters are respectively compared and evaluated on the basis of floating-point lossy compression and lossless-to-lossy compression. We also study the problems of the optimal unitary scaling factors and list initialization order. Finally, the best choices were found for a given application, via the extensive experiments and analyses. Moreover, in comparison with several state-of-the-art wavelet coding algorithms, 3-D EZBC can provide better compression performance and unsupervised classification accuracy. Experimental results show that the average lossy compression performance (in floating-point mode and integer-based mode) of our coder respectively outperforms 3-D set partitioning in hierarchical trees (SPIHT) by 1.26 dB, 3-D set-partitioned embedded block (SPECK) by 0.68 dB, symmetric-tree (AT) 3-D SPIHT by 0.39 dB, and JPEG 2000-MC by 0.25 dB at 0.1 to 3.0 bits per pixel per band, and the lossless coding performance of 3-D EZBC is about 5% to 7% better than that of 3-D SPECK, 3-D SPIHT, and AT 3-D SPIHT. So the 3-D EZBC algorithm is also a good candidate to compress hyperspectral images.

Compression-Aware Energy Optimization for Video Decoding Systems With Passive Power

The objective of dynamic voltage scaling (DVS) is to adapt the frequency and voltage for configurable platforms to obtain energy savings. DVS is especially attractive for video decoding systems due to their time-varying and highly complex workload and because the utility of decoding a frame is solely depending on the frame being decoded before its display deadline. Several DVS algorithms have been proposed for multimedia applications. However, the prior work did not take into account the video compression algorithm specifics, such as considering the temporal dependencies among frames and the required display buffer. Moreover, the effect of the passive (leakage) power when performing DVS for multimedia systems was not explicitly considered. In this paper, we determine the optimal scheduling of the active and passive states to minimize the total energy for video decoding systems. We pose our problem as a buffer-constrained optimization problem with a novel, compression-aware definition of processing jobs. We propose low-complexity algorithms to solve the optimization problem and show through simulations that significant improvements can be achieved over state-of-the art DVS algorithms that aim to minimize only the active power.

Custom parallel caching schemes for hardware-accelerated image compression

In an effort to achieve lower bandwidth requirements, video compression algorithms have become increasingly complex. Consequently, the deployment of these algorithms on field programmable gate arrays (FPGAs) is becoming increasingly desirable, because of the computational parallelism on these platforms as well as the measure of flexibility afforded to designers. Typically, video data are stored in large and slow external memory arrays, but the impact of the memory access bottleneck may be reduced by buffering frequently used data in fast on-chip memories. The order of the memory accesses, resulting from many compression algorithms are dependent on the input data (Jain in Proceedings of the IEEE, pp. 349–389, 1981). These data-dependent memory accesses complicate the exploitation of data re-use, and subsequently reduce the extent to which an application may be accelerated. In this paper, we present a hybrid memory sub-system which is able to capture data re-use effectively in spite of data-dependent memory accesses. This memory sub-system is made up of a custom parallel cache and a scratchpad memory. Further, the framework is capable of exploiting 2D spatial locality, which is frequently exhibited in the access patterns of image processing applications. In a case study involving the quad-tree structured pulse code modulation (QSDPCM) application, the impact of data dependence on memory accesses is shown to be significant. In comparison with an implementation which only employs an SPM, performance improvements of up to 1.7× and 1.4× are observed through actual implementation on two modern FPGA platforms. These performance improvements are more pronounced for image sequences exhibiting greater inter-frame movements. In addition, reductions of on-chip memory resources by up to 3.2× are achievable using this framework. These results indicate that, on custom hardware platforms, there is substantial scope for improvement in the capture of data re-use when memory accesses are data dependent.

Motion Compensated JPEG2000 based video compression algorithms

A new approach of Motion-Compensated JPEG2000 (MCJ2K) video compression is proposed in this paper. It uses simplified MPEG-2 fundamentals along with JPEG2000 encoding for compression of the image frames. MCJ2K generates differential images using motion compensation algorithms and store the motion vectors in a customised header. The images are then compressed using JPEG2000 based scheme. MCJ2K have been studied on QCIF and CIF formated videos for various rate control mechanism. The proposed scheme produced encouraging results compared to standard MPEG-2 and MJPEG2000 schemes, especially at higher bit rates.

모바일 화상통신을 위한 오류강인 부호화 기법

영상을 통신망에서 실시간 전송하려면 압축된 비디오 비트열이 필요하다. 비디오 압축 알고리즘은 시간적, 공간적, 확률적 중복성을 제거하기 때문에 부호화된 비트열은 전송과정 중에 발생하는 전송에러에 매우 민감한 특성을 보인다. 본 논문에서는 저 전송률 비디오 코딩에서 에러의 확산을 막기 위한 에러 복원코딩 방식을 제안한다. 이런 에러 복원 코딩 기술의 성능은 전송에러를 얼마나 정확하게 탐지해 내느냐에 달려 있는데, 전송 에러를 검출하기위해 데이터 숨김이라는 방식을 제안한다. 그리고 에러가 발생한 매크로블록을 복원하기 위해 인트라 매크로블록 갱신 기술과, 움직임 벡터 예측을 이용한 움직임 보상 기술을 적용하여 성능을 비교 및 평가한다. 이 방식은 WCDMA와 같이 에러가 발생할 확률이 있는 비디오 전송망에서 사용할 경우 매우 효과적이다. Compressed video bitstreams are intended for real-time transmission over communication networks. Because video compression algorithms eliminate the temporal, spatial, and statistical redundancies, the coded video bitstreams are very sensitive to transmission errors. We propose an error resilient video coding technique to limit the effect of error propagation in low bit-rate video coding. The success of error resilient coding techniques relies on how accurately the transmission errors can be detected. To detect the transmission error, we propose a very simple error detection technique based on data hiding Next, we conceal the corrupted MB data using intra MB refresh and motion compensation with the estimated motion vector and compare the simulation results. This method will be useful in video communication in error Prone environment such as WCDMA networks.

Time-Varying Mesh Compression Using an Extended Block Matching Algorithm

Time-varying mesh, which is attracting a lot of attention as a new multimedia representation method, is a sequence of 3-D models that are composed of vertices, edges, and some attribute components such as color. Among these components, vertices require large storage space. In conventional 2-D video compression algorithms, motion compensation (MC) using a block matching algorithm is frequently employed to reduce temporal redundancy between consecutive frames. However, there has been no such technology for 3-D time-varying mesh so far. Therefore, in this paper, we have developed an extended block matching algorithm (EBMA) to reduce the temporal redundancy of the geometry information in the time-varying mesh by extending the idea of the 2-D block matching algorithm to 3-D space. In our EBMA, a cubic block is used as a matching unit. MC in the 3-D space is achieved efficiently by matching the mean normal vectors calculated from partial surfaces in cubic blocks, which our experiments showed to be a suboptimal matching criterion. After MC, residuals are transformed by the discrete cosine transform, uniformly quantized, and then encoded. The extracted motion vectors are also entropy coded after differential pulse code modulation. As a result of our experiments, 10%-18% compression has been achieved.

Encoding of Affine Motion Vectors

An affine motion model provides better motion representation than a translational motion model. Therefore, it is a good candidate for advanced video compression algorithms, requiring higher compression efficiency than current algorithms. One disadvantage of the affine motion model is the increased number of motion vector parameters, therefore increased motion vector bit rate. We develop and analyze several simulation based approaches of entropy coding for orthonormalized affine motion vector (AMV) coefficients, by considering various context-types and coders. In our work we expand the traditional idea of a context type by introducing four new context types. We compare our method of contexts-type and coder selection with context quantization. The best of our contexts-type and coder solutions produces 4% to 15% average AMV bit-rate reductions over the original VLC approach. For more difficult content AMV bit rate reduction up to 26% is reported.

Multiparameter method for analysis and selection of motion estimation algorithms for video compression

This paper proposes a new multiparameter method for analysis and selection of motion estimation algorithms for video compression. We present motion estimation algorithms, results of computer simulations and illustrate the analysis with tables, PSNR and performance plots. Numerous algorithms and tests for analysis of algorithm performance for video compression have recently been suggested, which has resulted in a need for effective evaluation methods. A highly qualified expert is also needed to evaluate the test results. The more input parameters used the more complex and subjective the evaluation will be. Our multiparameter method for algorithm analysis and selection eliminates subjectivity and provides a qualitative and quantitative evaluation of the tested algorithms for any number of algorithms and parameters. We propose two new methods of evaluation: (1) a quality method--a graphic method using the Pareto approach, and (2) a quantity method which obtains an integrated parameter composed of numerous evaluation parameters. In addition, we evaluate various motion estimation algorithms accordingly to two different implementation strategies: (a) using a software video encoder that depends on available processing resources using a computational complexity---rate---distortion (C---R---D) evaluation framework and (b) using a power-limited video encoder implemented on mobile or handheld computing platform by using energy---rate---distortion (E---R---D) behavior.

The VC-1 Video Coding Standard

VC-1 is a new video coding standard developed by Microsoft and standardized by the SMPTE. VC-1 is one of the three video compression algorithms standardized for high definition DVD. With high definition DVD players expecting to support MPEG-2, H.264, and VC-1, end users do not have to be concerned about the coding formats. The VC-1 standard offers a competitive quality-complexity tradeoff compared to H.264, especially for high-definition services. With a diverse digital video market, we can expect to see VC-1 co-existing with H.264 in the next generation of broadband and broadcast video services.

Towards A Multi-Terminal Video Compression Algorithm By Integrating Distributed Source Coding With Geometrical Constraints

In this paper, we present a framework for multi- terminal video compression (MTVC) that exploits the geo- metric constraints between cameras with overlapping fields of view, and then uses distributed source coding on cor- responding points in two or more views. There are two main parts of the paper - a Distributed Motion Estimation (DME) algorithm and a Distributed Source Coding (DSC) algorithm. The novelty of the approach lies in the integration of these two parts. The overall algorithm is developed such that future improvements in either of the two parts can be integrated into it. We start by describing the algorithm for obtaining corresponding points followed by the distributed coding strategy. Our experiments provide a benchmark on the upper bound of the gain obtained through distributed coding of a pair of video sequences, as opposed to coding each of them separately. We also show results on a real- life face video sequence obtained by a pair of overlapping cameras. Through this experimental analysis, we show that at low bit-rates MTVC can achieve very significant savings.

Lossless Video Sequence Compression Using Adaptive Prediction

We present an adaptive lossless video compression algorithm based on predictive coding. The proposed algorithm exploits temporal, spatial, and spectral redundancies in a backward adaptive fashion with extremely low side information. The computational complexity is further reduced by using a caching strategy. We also study the relationship between the operational domain for the coder (wavelet or spatial) and the amount of temporal and spatial redundancy in the sequence being encoded. Experimental results show that the proposed scheme provides significant improvements in compression efficiencies.

Design of parallel algorithms for fractal video compression

The intrinsic independent features of the optimal codebook cubes searching process in fractal video compression systems are examined and exploited. The design of a suitable parallel algorithm reflecting the concept is presented. The Message Passing Interface (MPI) is chosen to be the communication tool for the implementation of the parallel algorithm on distributed memory parallel computers. Experimental results show that the parallel algorithm is able to reduce the compression time and achieve a high speed-up without changing the compression ratio and the quality of the decompressed image. A scalability test was also performed, and the results show that this parallel algorithm is scalable.

Optimizing Scalable Video Compression for Efficient Implementation on a VLIW Media Processor

State-of-the-art digital multimedia platforms contain a powerful very-long instruction word (VLIW) processing core. To obtain optimum performance on such a platform, a media-processing algorithm should exploit all the advantages provided by the VLIW processor's architecture. This paper focuses on a method for adapting a video compression algorithm for implementation on a VLIW processor using algorithm-architecture co-design. We demonstrate the importance of our adaptation approach and show the improved efficiency of the algorithm implementation

Rate-distortion analysis of motion-compensated rate scalable video

Generally speaking, rate scalable video systems today are evaluated operationally, meaning that the algorithm is implemented and the rate-distortion performance is evaluated for an example set of inputs. However, in these cases it is difficult to separate the artifacts caused by the compression algorithm and data set with general trends associated with scalability. In this paper, we derive and evaluate theoretical rate-distortion performance bounds for both layered and continuously rate scalable video compression algorithms which use a single motion-compensated prediction (MCP) loop. These bounds are derived using rate-distortion theory based on an optimum mean-square error (MSE) quantizer, and are thus applicable to all methods of intraframe encoding which use MSE as a distortion measure. By specifying translatory motion and using an approximation of the predicted error frame power spectral density, it is possible to derive parametric versions of the rate-distortion functions which are based solely on the input power spectral density and the accuracy of the motion-compensated prediction. The theory is applicable to systems which allow prediction drift, such as the data-partitioning and SNR-scalability schemes in MPEG-2, as well as those with zero prediction drift such as fine granularity scalability MPEG-4. For systems which allow prediction drift we show that optimum motion compensation is a sufficient condition for stability of the decoding system.

An affine-based algorithm and SIMD architecture for video compression with low bit-rate applications

This paper presents a new affine-based algorithm and SIMD architecture for video compression with low bit rate applications. The proposed algorithm is used for mesh-based motion estimation and it is named mesh-based square-matching algorithm (MB-SMA). The MB-SMA is a simplified version of the hexagonal matching algorithm [1]. In this algorithm, right-angled triangular mesh is used to benefit from a multiplication free algorithm presented in [2] for computing the affine parameters. The proposed algorithm has lower computational cost than the hexagonal matching algorithm while it produces almost the same peak signal-to-noise ratio (PSNR) values. The MB-SMA outperforms the commonly used motion estimation algorithms in terms of computational cost, efficiency and video quality (i.e., PSNR). The MB-SMA is implemented using an SIMD architecture in which a large number of processing elements has been embedded with SRAM blocks to utilize the large internal memory bandwidth. The proposed architecture needs 26.9 ms to process one CIF video frame. Therefore, it can process 37 CIF frames/s. The proposed architecture has been prototyped using Taiwan Semiconductor Manufacturing Company (TSMC) 0.18-/spl mu/m CMOS technology and the embedded SRAMs have been generated using Virage Logic memory compiler.