• Title/Summary/Keyword: 인트라 프레임 부호화기

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The design of high profile H.264 intra frame encoder (H.264 하이프로파일 인트라 프레임 부호화기 설계)

  • Suh, Ki-Bum
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.11
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    • pp.2285-2291
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    • 2011
  • In this paper, H.264 high profile intra frame encoder, which integrates intra prediction, context-based adaptive variable length coding(CAVLC), and DDR2 memory control module, is proposed. The designed encoder can be operated in 440 cycle for one-macroblock. In order to verify the encoder function, we developed the reference C from JM 13.2 and verified the developed hardware using test vector generated by reference C. The designed encoder is verified in the FPGA (field programmable gate array) with operating frequency of 200 MHz for DMA (direct memory access), operating frequency of 50 MHz of Encoder module, and 25 MHz for VIM(video input module). The number of LUT is 43099, which is about 20 % of Virtex 5 XC5VLX330.

East Algorithm for Intra Prediction in H.264 (H.264의 고속 인트라 예측 알고리듬)

  • 조량석;원치선
    • Proceedings of the IEEK Conference
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    • 2003.07e
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    • pp.1952-1955
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    • 2003
  • 최근에 표준화된 H.264 의 인트라 예측은 I-프레임을 압축하는데 사용된다. 최대의 코딩효율을 위해서 부호화기는 모든 인트라 예측 모드를 반복적으로 찾는다. 그러나 이것은 H.264 의 부호화기 복잡도를 매우 크게 하는 단점이 있다. 모든 경우의 모드중에 영상에 따라서는 특히 그 발생 가능성이 높거나 낮은 경우의 모드가 발생한다. 본 논문에서는 에지맵을 이용하여 H.264 의 인트라 예측 모드를 선별적으로 선택하는 방법을 제안한다.

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Quantization Level Selection of Intra-Frame for MPEG-4 Video Encoder (MPEG-4 부호화기에서의 인트라 프레임 양자화 레벨 선정)

  • Kim Jeong Woo;Cho Seong Hwan
    • Journal of Korea Multimedia Society
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    • v.8 no.1
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    • pp.9-18
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    • 2005
  • This paper presents the method of calculating the quantization level of the intra-frame in MPEG-4 video encoder. The intra-frame is an essential part in that the quality of the whole GOP is affected by the quality of this frame since the intra-frame, which works as a reference frame within GOP, continuously propagates through other frames. This work proposes how to use bits assigned for gaining the quantization level of the intra-frame, complexity of input images, and GOP structures. The result shows that while existing approaches have the decline in efficiency by using fixed values or show different qualifies depending on the characteristics of the images, the current approach shows the steady results in various images. Comparing with Q2 algorithm obtained in MPEG-4 VM, the approach suggested in this paper gains the benefit of maximum 3.49dB with some variations depending on the characteristics of the images.

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A Study on An Error-Resilient Constant Bit Rate Video Codec (에러 환경에 강한 항등비트율 동영상 부호화기에 관한 연구)

  • 한동원;송진규;김용구;최윤식
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.9B
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    • pp.1721-1730
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    • 1999
  • In this thesis, an error resilient video coding algorithm, under the error-prone environment such as wireless communication, is suggested. The suggested algorithm adapts the Classified VQ method for intra imagers that reduces some load by searching similar vectors. The Duplicate Vector Position Code is proposed for the higher compression efficiency and the robust decoding in error environment. As a result, the bitstream encoded by the proposed method is in a CBR(Constant Bit Rate) preventing from error propagation. The experiment that adds practical error to the encoded bitsrteam shows the error-robustness superior to H.263.

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Adaptive Hard Decision Aided Fast Decoding Method in Distributed Video Coding (적응적 경판정 출력을 이용한 고속 분산 비디오 복호화 기술)

  • Oh, Ryang-Geun;Shim, Hiuk-Jae;Jeon, Byeung-Woo
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.47 no.6
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    • pp.66-74
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    • 2010
  • Recently distributed video coding (DVC) is spotlighted for the environment which has restriction in computing resource at encoder. Wyner-Ziv (WZ) coding is a representative scheme of DVC. The WZ encoder independently encodes key frame and WZ frame respectively by conventional intra coding and channel code. WZ decoder generates side information from reconstructed two key frames (t-1, t+1) based on temporal correlation. The side information is regarded as a noisy version of original WZ frame. Virtual channel noise can be removed by channel decoding process. So the performance of WZ coding greatly depends on the performance of channel code. Among existing channel codes, Turbo code and LDPC code have the most powerful error correction capability. These channel codes use stochastically iterative decoding process. However the iterative decoding process is quite time-consuming, so complexity of WZ decoder is considerably increased. Analysis of the complexity of LPDCA with real video data shows that the portion of complexity of LDPCA decoding is higher than 60% in total WZ decoding complexity. Using the HDA (Hard Decision Aided) method proposed in channel code area, channel decoding complexity can be much reduced. But considerable RD performance loss is possible according to different thresholds and its proper value is different for each sequence. In this paper, we propose an adaptive HDA method which sets up a proper threshold according to sequence. The proposed method shows about 62% and 32% of time saving, respectively in LDPCA and WZ decoding process, while RD performance is not that decreased.

Wyner-Ziv Video Compression using Noise Model Selection (잡음 모델 선택을 이용한 Wyner-Ziv 비디오 압축)

  • Park, Chun-Ho;Shim, Hiuk-Jae;Jeon, Byeung-Woo
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.4
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    • pp.58-66
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    • 2009
  • Recently the emerging demands of the light-video encoder promotes lots of research efforts on DVC (Distributed Video Coding). As an appropriate video compression method, DVC has been studied, and Wyner-Ziv (WZ) video compression is its one representative structure. The WZ encoder splits the image into two kinds of frames, one is key frame which is compressed by conventional intra coding, and the other is WZ frame which is encoded by WZ coding. The WZ decoder decodes the key frame first, and estimates the WZ frame using temporal correlation between key frames. Estimated WZ frame (Side Information) cannot be the same as the original WZ frame due to the absence of the WZ frame information at decoder. As a result, the difference between the estimated and original WZ frames are regarded as virtual channel noise. The WZ frame is reconstructed by removing noise in side information. Therefore precise noise estimation produces good performance gain in WZ video compression by improving error correcting capability by channel code. But noise cannot be estimated precisely at WZ decoder unless there is good WZ frame information, and generally it is estimated from the difference of corresponding key frames. Also the estimated noise is limited by comparing with frame level noise to reduce the uncertainty of the estimation method. However these methods cannot provide good noise estimation for every frame or each bit plane. In this paper, we propose a noise nodel selection method which chooses a better noise model for each bit plane after generating candidate noise models. Experimental result shows PSNR gain up to 0.8 dB.

Voting-based Intra Mode Bit Skip Using Pixel Information in Neighbor Blocks (이웃한 블록 내 화소 정보를 이용한 투표 결정 기반의 인트라 예측 모드 부호화 생략 방법)

  • Kim, Ji-Eon;Cho, Hye-Jeong;Jeong, Se-Yoon;Lee, Jin-Ho;Oh, Seoung-Jun
    • Journal of Broadcast Engineering
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    • v.15 no.4
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    • pp.498-512
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    • 2010
  • Intra coding is an indispensable coding tool since it can provide random accessibility as well as error resiliency. However, it is the problem that intra coding has relatively low coding efficiency compared with inter coding in the area of video coding. Even though H.264/AVC has significantly improved the intra coding performance compared with previous video standards, H.264/AVC encoder complexity is significantly increased, which is not suitable for low bit rate interactive services. In this paper, a Voting-based Intra Mode Bit Skip (V-IMBS) scheme is proposed to improve coding efficiency as well as to reduce encoding time complexity using decoder-side prediction. In case that the decoder can determine the same prediction mode as what is chosen by the encoder, the encoder does not send that intra prediction mode; otherwise, the conventional H.264/AVC intra coding is performed. Simulation results reveal a performance increase up to 4.44% overall rate savings and 0.24 dB in peak signal-to-noise ratio while the frame encoding speed of proposed method is about 42.8% better than that of H.264/AVC.

An Additional Hardware Architecture for H .264/AVC Intra-Prediction (H.264/AVC의 프레임내 예측 부호화를 위한 부가적인 하드웨어 구조)

  • Lee Sujin;Kim Cheongghil;Kim Myoungseo;Kim Shindug
    • Proceedings of the Korean Information Science Society Conference
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    • 2005.07a
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    • pp.805-807
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    • 2005
  • H.264/AVC의 프레임내 예측기법은 현 매크로블록의 이웃픽셀들로부터 예측값을 추출함으로써 인트라 픽처의 압축률을 높이는데 크게 기여했다. 그러나 모든 매크로블록에 대해 총 17가지의 후보 모드를 검사해야 하기 때문에, 전체 부호화기의 복잡도를 상당히 상승시키는 요인이기도 하다. 본 논문에서는 이 문제를 해결하기 위해, 기존의 움직임 추정 전용 하드웨어로 주로 사용되는 1차원 시스톨릭 어레이 구조에 부가적인 하드웨어를 장착하여, 움직임 추정뿐만 아니라 프레임 내 예측까지 가능한 하드웨어 구조를 제안한다. 병렬적으로 끊김이 없는 수행을 위해 프레임내 예측 알고리즘을 약간 수정했으나, 이것은 화질이나 비트스트림 크기에 영향을 거의 미치지 않는다. 제안된 구조는 연산에 대한 명령어 개수로 비교할 때, ARM 기반 시스템에서 얻을 수 있는 성능의 10배에서 40배에 달하는 높은 성능을 보여준다.

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Adaptive Coding Mode Decision Algorithm using Motion Vector Map in H.264/AVC Video Coding (H.264/AVC 부호기에서 움직임 벡터 맵을 이용한 적응적인 부호화 모드 결정 방법)

  • Kim, Tae-Jung;Ko, Man-Geun;Suh, Jae-Won
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.2
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    • pp.48-56
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    • 2009
  • We propose a fast intra mode skip decision algorithm for H.264/AVC video encoding. Although newly added MB encoding algorithms based on various prediction methods increase compression ratio, they require a significant increase in the computational complexity because we calculate rate-distortion(RD) cost for all possible MB coding modes and then choose the best one. In this paper, we propose a fast mode decision algorithm based on an adaptive motion vector map(AMVM) method for H.264/AVC video encoding to reduce the processing time for the inter frame. We verify that the proposed algorithm generates generally good performances in PSNR, bit rates, and processing time.

Rate Distortion Improved Mode Decision Method for H.264 Intra Coding (H.264 인트라 프레임의 Rate Distortion 성능 향상을 위한 모드 결정 기법)

  • You, Jong-Min;Choi, Chang-Ryuol;Jeong, Je-Chang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.8C
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    • pp.591-597
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    • 2008
  • In this paper, we present a improved rate distortion optimization (RDO) for H.264 intra coding. By using new mode decision criteria pass for $I4{\times}4$ in company with the original RDO, the proposed method can achieve the better coding efficiency comparing with the original RDO. Our experimental results show that the proposed algorithm can archive about $0.64{\sim}1.6578%$ bit rate decrease at the same PSNR and $0.049{\sim}0.101dB$ PSNR increase at the same bit rate.