49 research outputs found

    Spatial Prediction in the H.264/AVC FRExt Coder and its Optimization

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    The chapter presents a review of the fast spatial prediction strategy that were designed for the Intra coding mode of the video coding standard H.264/AVC. At the end, the author presents an effective strategy based on belief propagation message passing

    Fast intra prediction in the transform domain

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    In this paper, we present a fast intra prediction method based on separating the transformed coefficients. The prediction block can be obtained from the transformed and quantized neighboring block generating minimum distortion for each DC and AC coefficients independently. Two prediction methods are proposed, one is full block search prediction (FBSP) and the other is edge based distance prediction (EBDP), that find the best matched transformed coefficients on additional neighboring blocks. Experimental results show that the use of transform coefficients greatly enhances the efficiency of intra prediction whilst keeping complexity low compared to H.264/AVC

    Skipping Strategies for High Definition H.264/AVC Real Time Video Coding

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    This paper discusses the feasibility of High Definition H.264/AVC video coding in the Baseline profile, for real time applications like videoconferencing. By means of suited SKIP strategies and exploiting the higher resolution, redundancyand visual information amount of the High Definition formats,with respect to Standard Definition, it is possible to speed upsignificantly the Mode Decision procedure, without affecting thefinal perceived quality

    Methodology and optimizing of multiple frame format buffering within FPGA H.264/AVC decoder with FRExt.

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    Digital representation of video data is an inherently resource demanding problem that continues to necessitate the development and refinement of coding methods. The H.264/AVC standard, along with its recent Fidelity Range Extensions amendment (FRExt), is quickly being adopted as the standard codec for broadcast and distribution of high definition video. The FRExt amendment, while not necessarily affecting the overall decoder architecture, presents an added complexity of providing efficient memory management for buffering intermediate frames of various pixel color samplings and depths. This thesis evaluated the role of designing the frame buffer of a hardware video decoder, with integrated support for the H.264/AVC codec plus FRExt. With focus on organizing external memory data access, the frame buffer was designed to provide intermediate data storage for the decoder, while using an efficient store and load scheme that takes into consideration each frame pixel format of the video data. VHDL was used to model the frame buffer. Exploitation of reconfigurability and post-synthesis FPGA simulations were used to evaluate behavior, scalability and power consumption, while providing an analysis of approaches to adding FRExt to the memory management. Real-time buffer performance was achieved for two common frame formats at 1080 HD resolution; and an innovative pipeline design provides dynamic switching of formats between video sequences. As an additional consequence of verifying the model, a preexisting Baseline H.264/AVC decoder testbench was augmented to support testing of multiple frame formats

    Improved lossless coding algorithm in H.264/AVC based on hierarchical intraprediction and coding-mode selection

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    Author name used in this publication: Li-Li Wang2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    A Fast Intra Prediction Based on Haar Transform in H.264/AVC

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    [[abstract]]H.264/AVC is one of the state of the art in video compressing standards. It has advantages of low bit-rate and high image quality. However, the omplexity of H.264/AVC encoder limits applications in the real time video communication. In this study, a fast intra prediction with Haar transform algorithm (FIPHTA) is proposed to simplify the complexity of luma intra prediction. For each luma macroblock (MB), a Haar transform is first executed. By observing LL coefficients, this MB will be classified as 16-MB, I4-MB, or both. An I16-MB indicates that this MB is smooth and only Intra 16Ã16 (I16) prediction modes are to be considered. An I4-MB indicates that this MB is textured and only Intra 4Ã4 (I4) prediction modes are to be considered. And the rest of MBs (both) have to consider both prediction modes as in the standard H.264/AVC. Next, to choose an I16 prediction mode for a MB, the vertical and horizontal energies of the LL coefficients are calculated to reduce candidate modes. Similarly, the pixel-based vertical and horizontal energies are calculated for a 4Ã4 block to reduce I4 candidate modes. The simulation showed that the proposed algorithm can maintain the similar mode selection results comparing to the full search algorithm of H.264 but with a remarkable computation deduction.[[sponsorship]]IEEE Taipei Section; National Science Council; Ministry of Education; Tamkang University; Asia University; Providence University; The University of Aizu; Lanzhou University[[conferencetype]]國際[[conferencetkucampus]]淡水校園[[conferencedate]]20091203~20091205[[iscallforpapers]]Y[[conferencelocation]]Taipei, Taiwa

    A hybrid system for video compression based on H.264 and JPEG2000

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    Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Includes bibliographical references (leaves 55-56).A video compression system is created that combines the JPEG2000 and H.264 standards. JPEG2000 is used to encode the I-frames, while H.264 is used to encode the P-frames. The goal of this thesis is to evaluate the performance of this hybrid system. The system is evaluated using a set of eight test video sequences, which cover a range of resolutions (CIF to 1920 x 1080) and picture content. Rate-distortion performance analysis shows the two systems to be comparable. Subjective analysis reveals that the artifacts of JPEG2000 are propagated to the P-frames. This can be useful in reducing blocking artifacts at low bit-rates. However, blurriness and fuzzy edges, which are the artifacts of JPEG2000, replace the blocking artifacts.by Zhenya Gu.M.Eng
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