Scalable video coding (SVC) has been standardized to extend the capabilities of the H.264 advanced video coding (AVC). The SVC can compress several video sequences of various resolutions as a single bit-stream. In the SVC enhancement layer, for Joint Scalable Video Model (JSVM) software implementation, an exhaustive mode decision process based on the base layer mode predictions is performed to obtain the best mode for each macroblock (MB). This technique may achieve a higher coding efficiency; however, it induces a significant computational complexity in the encoding engine. In order to speedup the SVC encoder, a fast mode decision algorithm was proposed in this paper. In other words, our aim was to decrease the number of candidate modes to reduce the computational complexity and maintain the same level of coding efficiency, this approach used the spatial and temporal correlation between MB situated at the enhancement layer and its co-located MB at the base layer. Our statistical analyses were made using several HD sequences with different motion characteristics. Experimental results show a significant improvement in terms of time encoding which is a major constraint for any real-time implementation. However, this gain is accompanied with an acceptable loss in video quality and a tolerable bit rate increase for most media supports. In fact, our proposed algorithm permits a major improvement that can reach up to 64.9 % in terms of computational effort. This gain will induce an average loss yield to 10.5 or 13.87 % that is comparable to the 13.12 % of the He Li's algorithm with an acceptable loss in terms of subjective video quality.

Re-sampling process is the technique used to create a new version of the image with different width and/or height in terms of pixels count. It may be either increasing the size of image so called upsampling or reducing its size so called down-sampling. In this paper we interest on down-sampling process. Hence, a DSP TMS320C6472 implementation of the down-sampling module is performed. The down-sampling method is based on poly-phase filter bank. A software design for this poly-phase filter interpolation on two levels is proposed in order to satisfy a significant time saving. Results show the efficiency of the down sampler filter especially for removing the aliasing artifacts. A good speed performance is performed for the two implementation design. For execution time results, we might attaint a gain of 33 % for multi-core design execution compared with the one core design.

With the introduction of diverse variety of display transmission and resolutions channel capacities, the joint Video Team has developed a new scalable video coding standard (H264/SVC) as an extension of H.264/AVC. In fact, it provides a single compressed bit-stream with several scalability levels. The spatial scalability is mainly based on coding tools such as inter-layer predictions that offer a better coding efficiency. In this paper, we present the impact of different inter layer prediction modes for spatial scalability. As a first step, analysis results show the significant role of inter-layer prediction process for coding efficiency. As a second step, role of each inter-layer prediction type is investigated. Simulations results demonstrate the significance of inter-layer intra prediction and inter-layer residual prediction when targeting a better coding efficiency.

The high performance of H.264/AVC video encoder is accompanied with a wide computation complexity especially for high definition (HD) video sequences.One of the major H.264/AVC features to be optimized is the mode decision for both inter and intra prediction.Thus, based on high correlation observed between selected inter prediction mode and intra mode decision, a fast intra mode decision algorithm based on the best inter prediction mode for H264 high definition (HD) baseline profile encoder is proposed.The evaluation of the proposed approach was based on the rate distortion and PSNR variation, execution time and percentage of skipping intra4x4 and intra16x16.The proposed scheme is performed on 720p (1280x720) and 1080p (1920x1088) HD video sequences.Experimental results show that the proposed algorithm can save up to 60% of intra prediction computation time, 16% of skipping intra16x16 and up to 83% for intra4x4 without inducing PSNR degradation and bit-rate increase.

This paper proposes a fast intra mode decision approach based on the best inter prediction mode for P frames. This investigation is motivated by the high correlation observed between selected inter prediction mode and intra mode decision. The aim of this work is reducing computational complexity of the intra prediction module for H.264/AVC baseline encoder without inducing visual quality degradation or bit-rate increase. The evaluation of the proposed scheme was based on the rate distortion criteria and the execution time. Experimental results show that the proposed algorithm can save up to 60% of intra prediction computation time and maintain similar PSNR quality without inducing a bit-rate increase.

This paper proposes a fast intra mode decision approach based on the best inter prediction mode for P frames. This investigation is motivated by the high correlation observed between selected inter prediction mode and intra mode decision. The aim of this work is reducing computational complexity of the intra prediction module for H.264/AVC baseline encoder without inducing visual quality degradation or bit-rate increase. The evaluation of the proposed scheme was based on the rate distortion criteria and the execution time. Experimental results show that the proposed algorithm can save up to 60% of intra prediction computation time and maintain similar PSNR quality without inducing a bit-rate increase.

A common method for selecting the best prediction mode based on block matching algorithm is to compare, for each source block, the associated distortions among the available prediction candidates. The human visual perception is sensitive to luminance contrast rather than absolute luminance values. In fact, the human eyes ability to detect the magnitude difference between an object and its background depends on the background luminance average value. The Perceptually Weighted Distortion (PWD) is a new distortion measure that can produce better image quality. In this paper, we propose to add a new feature to the PWD by introducing another diagonal component that yields to a significant quality improvement. The enhanced PWD metric actually outperforms the original PWD and the SAD metric, according to the experimental results, especially in the aspect of reducing block artifacts. An increase in terms of implementation complexity will be noticed as a result of this contribution. Therefore, optimized implementation of the Enhanced PWD exploiting the C64 DSP-Core assets will be presented. In fact, Standard Assembly (SA) is used to implement the different Enhanced PWD functions in order to exploit efficiently the C64 internal architecture and resources. Experimental results show more than 85% improvement in terms of cycle cost compared to C code.

the introduction of diverse variety of display transmission and resolutions channel capacities, the Joint Video Team (JVT) has developed the H.264/SVC as an extension of H.264/AVC. In fact, it provides a single compressed bit-stream with several scalability levels. Such a dataflow needs to be analyzed. Consequently, this paper is the first that decorticates and investigates the H264/SVC bit-stream in order to highlight its contribution from one hand and to analyze deeply the different sub bit-stream modules in terms of size and importance on the other hand. Results of a first analysis shows that multicast coding using H264/SVC standard provides an average bit rate reduction of 18% compared to simulcast. Second analysis demonstrates the importance of inter layer prediction. Then a third study illustrates two best combinations for two network bandwidth limitation. Finally, analysis of different subfields that constitute H264/SVC bit stream shows the importance of the residual module which can form up to 72% of the total data output. Results also illustrate the significance of the inter-layer prediction. In fact, base layer information takes the lion's share of bit consumption mainly for B frame.

Motion Estimation module in H.264/AVC video encoder has the most computational load and memory access complexity, since it includes integer and fractional motion vector estimation. In the present paper, fractional motion estimation process analysis is performed based on which a Digital Signal Processor (DSP) specific optimized implementation is developed. The integration of the interpolation module decreases drastically the encoding speed when improving rate distortion performance. To overpass encoding speed degradation, parallelism between algorithm execution and data transfers were fully exploited using Enhanced Direct Memory Access engine (EDMA). Furthermore, based on the DSP architectural features, core specific optimization techniques were adopted leading to reduce the interpolation module complexity up to 70%.

The coding gain of the H.264/AVC video encoder mainly comes from the new incorporated prediction tools. However, their enormous computation and ultrahigh memory bandwidth are the penalties. In this paper we present an approach supporting efficient data reuse process to avoid unnecessary memory accesses and redundant motion estimation computations combined with a novel fast algorithm. A merging procedure joining search origin, search pattern and new variable block size motion estimation for H.264/AVC is detailed in this paper. Those approaches yield good tradeoffs between motion estimation distortion and number of computations since they invest and exploit the centre-biased characteristics of the real world video sequences: a reliable predictor determines the search origin, localizing the search process. An efficient search pattern exploits structural constraints within the motion field. A new fast block size selection DSP-based algorithm allows simultaneous fidelity of the video quality and the reduction of the computational cost. Extensive experimental work has been done, results of which show that our approach gives a speed up of 1.14 times over that of the recent fast algorithms and 10 times over the spiral search algorithm on average, with a negligible degradation in peak signal-to-noise ratio. In addition, interesting memory bandwidth is further saved with the proposed data reuse techniques at architecture level.

The widespread of video based applications in nowadays life has increased the need of video coding scalability. In fact, spatial scalability allows the adaptation of the bit-stream to end users as well as varying terminal capabilities and network conditions. In this context, many Discrete Wavelet Transform (DWT) based video codec are proposed. We can sort out that the well known integer to integer DWT such as 5/3 and 9/7-M filters do not perform well in coding the residual frames of the video in terms of PSNR.

Entropy coding is a fundamental stage in all video compression algorithms in terms of compression efficiency and error resilience. In this paper we propose and optimize a digital signal processor (DSP)-based implementation of the CAVLC tools for the H.264 Baseline encoder. As result, we have been able to generate the bit stream and supply bit rate result: the LETI encoder is able to achieve high compression performance when proposing interesting video quality.

Summary A merging procedure joining search origin, search pattern and new variable block size motion estimation for H.264/AVC is proposed in this paper. Those approaches yield good tradeoffs between motion estimation distortion and number of computations since they invest and exploit the center-biased characteristics of the real world video sequences: A reliable predictor determines the search origin, localizing the search process. An efficient search pattern exploits structural constraints within the motion field. A new fast block size selection DSPbased algorithm allows simultaneous fidelity of the video quality and the reduction of the computational cost. Experimental results demonstrate the viability of the proposed algorithms in low bit rate video coding applications: Video conference. The proposed motion estimation algorithms provide substantially higher encoding speed as well as graceful computational degradation capabilities.

Summary Motion estimation and compensation techniques are widely used for video coding applications but the real-time motion estimation is not easily achieved due to its enormous computations. Therefore, it would be greatly beneficial to optimize as much as possible the motion estimation bloc which is considered to be the most important in terms of computational cost. In this paper, a new fast block size selection DSP-based algorithm is presented, in which computation complexity is greatly reduced when achieving the same video quality. Experimental results show a 45.75% improvement in speed with no major loss in video quality (objective (PSNR) and subjective (SSIM)).

A merging procedure joining search pattern and variable block size motion estimation for H.264/AVC is proposed in this paper. The principal purpose of the proposed methods is the reduction of the computational complexity for block matching module. In fact, there are numerous contributions in the literature aiming the reduction of the computational cost needed for motion estimation. The best solution from a qualitative point of view is the full search that considers every possible detail. The computational effort required is enormous and this makes motion estimation by far the most important computational bottleneck in video coding systems. Our approach invests and exploits the center-biased characteristics of the real world video sequences, aiming to achieve an acceptable image quality while independently targeting the reduction of the computational complexity. The simulations results demonstrated that the proposal performs well.

In this paper we study the computational complexity of the intra/inter prediction modules for video coding software according to H.264/AVC standard. We analyse separately the complexity of each mode toward an implementation on TMS320C64 platform. Since any real-time implementation is considered to be time and money consuming, complexity pre-analysis of any giving video-coding algorithm is very important to determine not only software bottlenecks, but also the minimum hardware resources and characteristics required for the targeted platform. To estimate the total complexity of the prediction processes (intra/inter), we assume that the encoder tests all modes. The total cycle's account is estimated by multiplying the number of cycles of each mode by the number of macroblocks in the frame. Simulation results indicate that our methodology for the complexity analyses for H.264/AVC prediction modules provides a good approximation with respect to the experimental results. Copyright (C) 2006 AEIT.

With the increasing usage of multimedia technologies, image compression requires higher performance as well as new features. To address these needs in the specific area of continuous tone still image encoding, a new standard is currently being developed, JPEG2000. We first present an overview of this standard. We are interested in evaluation of its performance by means of Kakadu software.