• Title/Summary/Keyword: Inter mode

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A Fast Mode Decision of Non-anchor Pictures in Multi-view Video Coding for 3D Applications (3D 응용을 위한 다시점 영상 부호화에서 비기준 화면의 빠른 모드결정 기법)

  • Jung, Choong-Hyun;Shin, Kwang-Mu;Park, Seong-Ho;Chung, Ki-Dong
    • Journal of Korea Multimedia Society
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    • v.15 no.7
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    • pp.859-869
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    • 2012
  • The Multi-view Video Coding (MVC) which is exploiting disparities between views has been developed to improve the coding efficiency of multi-view video. But MVC has a problem of having high computing complexities because of disparity estimation. This paper propose a fast mode decision for non-anchor picture to reduce the computational time of MVC. The proposed method uses two phases. Anchor pictures in hierarchical B picture structure have a higher correlation with prediction mode selection of non-anchor pictures, so in the first phase, prediction mode of non-anchor pictures is selected by exploiting the macro-block regions in anchor picture. In the second phase, we select a reference direction of inter prediction mode exploiting a higher correlation among reference directions of inter prediction modes of 7 block sizes. Experimental results show that the proposed method could save average about 44% in the encoding time with negligible coding efficiency losses.

Integrating Directed-Based Fuzzing with AFL++ in QEMU Mode (QEMU 모드에서 AFL++와 Directed-Based Fuzzing 의 통합)

  • Jin-myung Choi;Hyunjun Kim;Martin Kayondo;Yun-heung Paek
    • Proceedings of the Korea Information Processing Society Conference
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    • 2024.05a
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    • pp.271-274
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    • 2024
  • Fuzzing is widely used as a testing tool to identify vulnerabilities in software programs. Although AFL++ has emerged to facilitate the integration and development of many fuzzers, there are still numerous advance fuzzing technologies that have not yet been incorporated. Among these, we have integrated state-of-the-art directed-based fuzzing techniques into AFL++ to operate in QEMU mode.

Operation-level Early Termination Algorithm for Inter-predictions in HEVC

  • Rhee, Chae Eun
    • IEIE Transactions on Smart Processing and Computing
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    • v.5 no.4
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    • pp.235-242
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    • 2016
  • The emerging High-Efficiency Video Coding (HEVC) standard attempts to improve coding efficiency by a factor of two over H.264/Advanced Video Coding (AVC) at the expense of an increase in computational complexity. Mode decision with motion estimation (ME) is still one of the most time-consuming computations in HEVC, as it is with H.264/AVC. Thus, fast mode decisions are not only an important issue to be researched, but also an urgent one. Several schemes for fast mode decisions have been presented in reference software and in other studies. However, the conventional hierarchical mode decision can be useless when block-level parallelism is exploited. This paper proposes operation-level exploration that offers more chances for early termination. An early termination condition is checked between integer and fractional MEs and between the parts of one partition type. The fast decision points of the proposed algorithm do not overlap those in previous works. Thus, the proposed algorithms are easily used with other fast algorithms, and consequently, independent speed-up is possible.

A Fast Inter-prediction Mode Decision Algorithm for HEVC Based on Spatial-Temporal Correlation

  • Yao, Weixin;Yang, Dan
    • Journal of Information Processing Systems
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    • v.18 no.2
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    • pp.235-244
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    • 2022
  • Many new techniques have been adopted in HEVC (High efficiency video coding) standard, such as quadtree-structured coding unit (CU), prediction unit (PU) partition, 35 intra-mode, and so on. To reduce computational complexity, the paper proposes two optimization algorithms which include fast CU depth range decision and fast PU partition mode decision. Firstly, depth range of CU is predicted according to spatial-temporal correlation. Secondly, we utilize the depth difference between the current CU and CU corresponding to the same position of adjacent frame for PU mode range selection. The number of traversal candidate modes is reduced. The experiment result shows the proposed algorithm obtains a lot of time reducing, and the loss of coding efficiency is inappreciable.

Adaptive Initial QP Determination Algorithm for Low Bit Rate Video Coding (저전송률 비디오 압축에서 적응적 초기 QP 결정 알고리즘)

  • Park, Sang-Hyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.9
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    • pp.1957-1964
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    • 2010
  • In Video coding, the first frame is encoded in intra mode which generates a larger number of bits. In addition, the first frame is used for the inter mode encoding of the following frames. Thus the intial QP for the first frame of GOP affects the first frame as well as the following frames. Traditionally, the initial QP of a GOP is determined by the initial QP of the previous GOP and the average QP of the inter mode frames. In case of JM, the initial QP of a GOP is adjusted as the initial QP being less than the average QP of inter mode frames by two. However, this method is not suitable for the low bit rate video coding. In this paper, the linear relationship between the optimal QP and the ratio of the PSNR of the first frame and the average PSNR of the inter mode frames is first investigated and the linear model is proposed based on the results of the investigation. The proposed model calculate the optimal initial QP using the encoding results of the previous GOP. It is shown by experimental results that the new algorithm can predict the optimal initial QP more accurately and generate the PSNR performance better than that of the existing JM algorithm.

Fast CU Encoding Schemes Based on Merge Mode and Motion Estimation for HEVC Inter Prediction

  • Wu, Jinfu;Guo, Baolong;Hou, Jie;Yan, Yunyi;Jiang, Jie
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.3
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    • pp.1195-1211
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    • 2016
  • The emerging video coding standard High Efficiency Video Coding (HEVC) has shown almost 40% bit-rate reduction over the state-of-the-art Advanced Video Coding (AVC) standard but at about 40% computational complexity overhead. The main reason for HEVC computational complexity is the inter prediction that accounts for 60%-70% of the whole encoding time. In this paper, we propose several fast coding unit (CU) encoding schemes based on the Merge mode and motion estimation information to reduce the computational complexity caused by the HEVC inter prediction. Firstly, an early Merge mode decision method based on motion estimation (EMD) is proposed for each CU size. Then, a Merge mode based early termination method (MET) is developed to determine the CU size at an early stage. To provide a better balance between computational complexity and coding efficiency, several fast CU encoding schemes are surveyed according to the rate-distortion-complexity characteristics of EMD and MET methods as a function of CU sizes. These fast CU encoding schemes can be seamlessly incorporated in the existing control structures of the HEVC encoder without limiting its potential parallelization and hardware acceleration. Experimental results demonstrate that the proposed schemes achieve 19%-46% computational complexity reduction over the HEVC test model reference software, HM 16.4, at a cost of 0.2%-2.4% bit-rate increases under the random access coding configuration. The respective values under the low-delay B coding configuration are 17%-43% and 0.1%-1.2%.

A Fast Inter-layer Mode Decision Method inScalable Video Coding (공간적 스케일러블 비디오 부호화에서 계층간 모드 고속 결정 방법)

  • Lee, Bum-Shik;Hahm, Sang-Jin;Park, Chang-Seob;Park, Keun-Soo;Kim, Mun-Churl
    • Journal of Broadcast Engineering
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    • v.12 no.4
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    • pp.360-372
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    • 2007
  • We propose a fast inter-layer mode decision method by utilizing coding information of base layer upward its enhancement layer inscalable video coding (SVC), also called MPEG-4 part 10 Advanced Video Coding Amendment 3 or H.264 Scalable Extension (SE) which is being standardized. In this paper, when the motion vectors from the base layer have zero motion (0, 0) in inter-layer motion prediction or the Integer Transform coefficients of the residual between current MB and the motion compensated MB by the predicted motion vectors from the base layer are all zero, the block mode of the corresponding block to be encoded at the enhancement layer is determined to be the $16{\times}16$ mode. In addition, if the predicted mode of the MB to be encoded at the enhancement layer is not equal to the $16{\times}16$ mode, then the rate-distortion optimization is only performed on the reduced candidated modes which are same or smaller partitioned modes. Our proposed method exhibits the complexity reduction in encoding time up to 72%. Nevertheless, it shows negligible PSNR degradation and bit rate increase up to 0.25dB and 1.73%, respectively.

Phase Mode Decision Scheme for Fast Encoding in H.264 SVC (H.264/AVC 스케일러블 비디오 코딩에서 빠른 부호화를 위한 단계적 모드 선택 기법)

  • Goh, Gyeong-Eun;Kang, Jin-Mi;Cho, Mi-Sook;Chung, Ki-Dong
    • Journal of KIISE:Computing Practices and Letters
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    • v.14 no.8
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    • pp.793-797
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    • 2008
  • To achieve flexible visual contents adaptation for multimedia communications, the ISO/IEC MPEG & ITU-T VCEG form the JVT to develop an SVC amendment for the H.264/AVC standard. JVT uses inter-layer prediction that can improve the rate-distortion efficiency of the enhancement layer. But inter-layer prediction causes computational complexity to be increased. In this paper, we propose a fast mode decision for inter frame coding. It makes use of the correlation between optimized prediction mode and its RD cost. Experimental results show that the proposed schemes save up to 38% of encoding time with a negligible coding loss and bit-rate increase.

An Efficient Mode Decision and Search Region Restriction for Fast Encoding of H.264/AVC (H.264/AVC의 빠른 부호화를 위한 효율적인 모드 결정과 탐색영역 제한)

  • Chun, Sung-Hwan;Shin, Kwang-Mu;Kang, Jin-Mi;Chung, Ki-Dong
    • Journal of Korea Multimedia Society
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    • v.13 no.2
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    • pp.185-195
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    • 2010
  • In this paper, we propose an efficient inter and intra prediction algorithms for fast encoding of H.264/AVC. First, inter prediction mode decision method decides early using temporal/spatial correlation information and pixel direction information. Second, intra prediction mode decision method selects block size judging smoothness degree with inner/outer pixel value variation and decides prediction mode using representative pixel and reference pixel. Lastly, adaptive motion search region restriction sets search region using mode information of neighboring block and predicted motion vector. The experimental results show that proposed method can achieve about 18~53% reduction compared with the existing JM 14.1 in the encoding time. In RD performance, the proposed method does not cause significant PSNR value losses while increasing bitrates slightly.

Free vibrations of a two-cable network inter-supported by cross-links extended to ground

  • Zhou, H.J.;Wu, Y.H.;Li, L.X.;Sun, L.M.;Xing, F.
    • Smart Structures and Systems
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    • v.23 no.6
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    • pp.653-667
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    • 2019
  • Using cross-ties to connect cables together when forming a cable network is regarded as an efficient method of mitigating cable vibrations. Cross-ties have been extended and fixed on bridge decks or towers in some engineering applications. However, the dynamics of this kind of system need to be further studied, and the effects of extending cross-links to bridge decks/towers on the modal response of the system should be assessed in detail. In this paper, a system of two cables connected by an inter-supported cross-link with another lower cross-link extended to the ground is proposed and analyzed. The characteristic equation of the system is derived, and some limiting solutions in closed form of the system are derived. Roots of cable system with special configurations are also discussed, attention being given to the case when the two cables are identical. A predictable mode behavior was found when the stiffness of inter-connection cross-link and the cross-link extended to the ground were the same. The vector of mode energy distribution and the degree of mode localization index are proposed so as to distinguish global and local modes. The change of mode behaviors is further discussed in the case when the two cables are not identical. Effects of cross-link stiffness, cross-link location, mass-tension ratio, cable length ratio and frequency ratio on $1^{st}$ mode frequency and mode shape are addressed.