759 research outputs found

    Architecture design of a scalable adaptive deblocking filter for H.264/AVC

    Get PDF
    Due to significant bit-rate savings and improved perceptual quality, H.264/AVC, the latest video compression standard from the Joint Video Team, is receiving widespread adoption. Greater coding efficiency relative to previous standards is a result of additional techniques and features. One important change is the inclusion of an in-loop deblocking filter for removal of blocking artifacts. Since the filter can easily account for one-third of the computational complexity of a decoder, its addition was a source of debate during the development of the H.264/AVC standard. Ample research on architecture design of the deblocking filter has been carried out, generally targeted toward high performance profiles. To the best of our knowledge no other research investigated designs that can be scaled from low-power extended profiles up to high performance profiles. This work investigated the design of a scalable architecture for the deblocking filter. Four different designs were implemented. The relative performance of the designs were then compared against each other and existing research through simulation. All designs were targeted towards a Xilinx Virtex 5 field programmable gate array (FPGA)

    Adaptive deblocking filter for transform domain Wyner-Ziv video coding

    Get PDF
    Wyner-Ziv (WZ) video coding is a particular case of distributed video coding, the recent video coding paradigm based on the Slepian-Wolf and Wyner-Ziv theorems that exploits the source correlation at the decoder and not at the encoder as in predictive video coding. Although many improvements have been done over the last years, the performance of the state-of-the-art WZ video codecs still did not reach the performance of state-of-the-art predictive video codecs, especially for high and complex motion video content. This is also true in terms of subjective image quality mainly because of a considerable amount of blocking artefacts present in the decoded WZ video frames. This paper proposes an adaptive deblocking filter to improve both the subjective and objective qualities of the WZ frames in a transform domain WZ video codec. The proposed filter is an adaptation of the advanced deblocking filter defined in the H.264/AVC (advanced video coding) standard to a WZ video codec. The results obtained confirm the subjective quality improvement and objective quality gains that can go up to 0.63 dB in the overall for sequences with high motion content when large group of pictures are used

    An efficient hardware architecture for H.264 adaptive deblocking filter algorithm

    Get PDF
    This paper presents an efficient hardware architecture for real-time implementation of adaptive deblocking filter algorithm used in H.264 video coding standard. This hardware is designed to be used as part of a complete H.264 video coding system for portable applications. We use a novel edge filter ordering in a Macroblock to prevent the deblocking filter hardware from unnecessarily waiting for the pixels that will be filtered become available. The proposed architecture is implemented in Verilog HDL. The Verilog RTL code is verified to work at 72 MHz in a Xilinx Virtex II FPGA. The FPGA implementation can code 30 CIF frames (352x288) per second

    Quality Adaptive Least Squares Trained Filters for Video Compression Artifacts Removal Using a No-reference Block Visibility Metric

    No full text
    Compression artifacts removal is a challenging problem because videos can be compressed at different qualities. In this paper, a least squares approach that is self-adaptive to the visual quality of the input sequence is proposed. For compression artifacts, the visual quality of an image is measured by a no-reference block visibility metric. According to the blockiness visibility of an input image, an appropriate set of filter coefficients that are trained beforehand is selected for optimally removing coding artifacts and reconstructing object details. The performance of the proposed algorithm is evaluated on a variety of sequences compressed at different qualities in comparison to several other deblocking techniques. The proposed method outperforms the others significantly both objectively and subjectively

    An Analysis of VP8, a new video codec for the web

    Get PDF
    Video is an increasingly ubiquitous part of our lives. Fast and efficient video codecs are necessary to satisfy the increasing demand for video on the web and mobile devices. However, open standards and patent grants are paramount to the adoption of video codecs across different platforms and browsers. Google On2 released VP8 in May 2010 to compete with H.264, the current standard of video codecs, complete with source code, specification and a perpetual patent grant. As the amount of video being created every day is growing rapidly, the decision of which codec to encode this video with is paramount; if a low quality codec or a restrictively licensed codec is used, the video recorded might be of little to no use. We sought to study VP8 and its quality versus its resource consumption compared to H.264 -- the most popular current video codec -- so that reader may make an informed decision for themselves or for their organizations about whether to use H.264 or VP8, or something else entirely. We examined VP8 in detail, compared its theoretical complexity to H.264 and measured the efficiency of its current implementation. VP8 shares many facets of its design with H.264 and other Discrete Cosine Transform (DCT) based video codecs. However, VP8 is both simpler and less feature rich than H.264, which may allow for rapid hardware and software implementations. As it was designed for the Internet and newer mobile devices, it contains fewer legacy features, such as interlacing, than H.264 supports. To perform quality measurements, the open source VP8 implementation libvpx was used. This is the reference implementation. For H.264, the open source H.264 encoder x264 was used. This encoder has very high performance, and is often rated at the top of its field in efficiency. The JM reference encoder was used to establish a baseline quality for H.264. Our findings indicate that VP8 performs very well at low bitrates, at resolutions at and below CIF. VP8 may be able to successfully displace H.264 Baseline in the mobile streaming video domain. It offers higher quality at a lower bitrate for low resolution images due to its high performing entropy coder and non-contiguous macroblock segmentation. At higher resolutions, VP8 still outperforms H.264 Baseline, but H.264 High profile leads. At HD resolution (720p and above), H.264 is significantly better than VP8 due to its superior motion estimation and adaptive coding. There is little significant difference between the intra-coding performance between H.264 and VP8. VP8\u27s in-loop deblocking filter outperforms H.264\u27s version. H.264\u27s inter-coding, with full support for B frames and weighting outperforms VP8\u27s alternate reference scheme, although this may improve in the future. On average, VP8\u27s feature set is less complex than H.264\u27s equivalents, which, along with its open source implementation, may spur development in the future. These findings indicate that VP8 has strong fundamentals when compared with H.264, but that it lacks optimization and maturity. It will likely improve as engineers optimize VP8\u27s reference implementation, or when a competing implementation is developed. We recommend several areas that the VP8 developers should focus on in the future

    Mitigation of H.264 and H.265 Video Compression for Reliable PRNU Estimation

    Full text link
    The photo-response non-uniformity (PRNU) is a distinctive image sensor characteristic, and an imaging device inadvertently introduces its sensor's PRNU into all media it captures. Therefore, the PRNU can be regarded as a camera fingerprint and used for source attribution. The imaging pipeline in a camera, however, involves various processing steps that are detrimental to PRNU estimation. In the context of photographic images, these challenges are successfully addressed and the method for estimating a sensor's PRNU pattern is well established. However, various additional challenges related to generation of videos remain largely untackled. With this perspective, this work introduces methods to mitigate disruptive effects of widely deployed H.264 and H.265 video compression standards on PRNU estimation. Our approach involves an intervention in the decoding process to eliminate a filtering procedure applied at the decoder to reduce blockiness. It also utilizes decoding parameters to develop a weighting scheme and adjust the contribution of video frames at the macroblock level to PRNU estimation process. Results obtained on videos captured by 28 cameras show that our approach increases the PRNU matching metric up to more than five times over the conventional estimation method tailored for photos

    Parallel deblocking filtering in MPEG-4 AVC/H.264 on massively parallel architectures

    Get PDF
    The deblocking filter in the MPEG-4 AVC/H.264 standard is computationally complex because of its high content adaptivity, resulting in a significant number of data dependencies. These data dependencies interfere with parallel filtering of multiple macroblocks (MBs) on massively parallel architectures. In this letter, we introduce a novel MB partitioning scheme for concurrent deblocking in the MPEG-4 AVC/H. 264 standard, based on our idea of deblocking filter independency, a corrected version of the limited error propagation effect proposed in the letter. Our proposed scheme enables concurrent MB deblocking of luma samples with limited synchronization effort, independently of slice configuration, and is compliant with the MPEG-4 H.264/AVC standard. We implemented the method on the massively parallel architecture of the graphics processing unit (GPU). Experimental results show that our GPU implementation achieves faster-than real-time deblocking at 1309 frames per second for 1080p video pictures. Both software-based deblocking filters and state-of-the-art GPU-enabled algorithms are outperformed in terms of speed by factors up to 10.2 and 19.5, respectively, for 1080p video pictures

    Network-on-Chip Based H.264 Video Decoder on a Field Programmable Gate Array

    Get PDF
    This thesis develops the first fully network-on-chip (NoC) based h.264 video decoder implemented in real hardware on a field programmable gate array (FPGA). This thesis starts with an overview of the h.264 video coding standard and an introduction to the NoC communication paradigm. Following this, a series of processing elements (PEs) are developed which implement the component algorithms making up the h.264 video decoder. These PEs, described primarily in VHDL with some Verilog and C, are then mapped to an NoC which is generated using the CONNECT NoC generation tool. To demonstrate the scalability of the proposed NoC based design, a second NoC based video decoder is implemented on a smaller FPGA using the same PEs on a more compact NoC topology. The performance of both decoders, as well as their component PEs, is evaluated on real hardware. An analysis of the performance results is conducted and recommendations for future work are made based on the results of this analysis. Aside from the development of the proposed decoder, a major contribution of this thesis is the release of all source materials for this design as open source hardware and software. The release of these materials will allow other researchers to more easily replicate this work, as well as create derivative works in the areas of NoC based designs for FPGA, video coding and decoding, and related areas
    corecore