• Title/Summary/Keyword: Entropy Coding

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Codebook Reordering Technique for Entropy Coding of VQ Indexes (VQ 인덱스의 엔트로피 부호화를 위한 코드북 재정렬 기법)

  • Hwang, Jae-Ho;Hong, Choong-Seon;Lee, Dae-Young
    • Proceedings of the Korea Information Processing Society Conference
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    • 2000.10b
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    • pp.903-906
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    • 2000
  • 웨이브렛 영역에서 벡터 양자화(vector quantization)를 수행하여 생성된 VQ 인덱스들을 엔트로피 부호화(entropy coding)하면 영상의 코딩 효율을 높일 수 있다. 본 논문에서는 벡터 양자화 이전에 VQ 인덱스들의 중복성을 높이기 위해 다중해상도 코드북의 코드 워드들을 에너지 크기 순으로 재정렬하는 기법을 제안한다. 코드 워드들의 평균과 편차를 이용한 재정렬 방법과 제안된 기법을 벡터 양자화 후 생성되는 VQ 인덱스에 DPCM/Huffman 기법을 적용하여 각각에 대한 코딩 효율을 비교한다.

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The Research of Efficient Context Coding Method for compression of High-resolution image in JPEG 2000 (고해상도 정지영상 압축을 위한 효율적인 JPEG2000용 Context 추출부의 연산 방법 연구)

  • Lee, Sung-Mok;Song, Jin-Gun;Ha, Joo-Young;Lee, Min-Woo;Kang, Bong-Soon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2007.10a
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    • pp.97-100
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    • 2007
  • In order to overcome many defects in the current JPEG standard of still image compression, the new JPEG2000 standard has been development. The JPEG2000 standard is based on the principles of DWT and EBCOT Entropy Coding. EBCOT(Embedded block coding with optimized truncation) is the most important technology in the latest image-coding standard, JPEG2000. However, EBCOT occupies the highest computation time to operate bit-level processing. Therefore, many researches have achieved methods to minimize computation speed of EBCOT. Thus, this paper proposes the method of context-extraction that improves computational architecture. This paper proposes efficient context coding method. The proposed algorithm would apply to hard-wired JPEG2000 Encoder that is used for compression of high resolution image.

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Enhanced Image Encryption Scheme using Context Adaptive Variable Length Coding (적응 산술 부호화를 이용한 고화질 영상 암호화 전략)

  • Shim, Gab-Yong;Lee, Malrey
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.13 no.3
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    • pp.119-126
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    • 2013
  • Achieve real-time encryption and video data transcoding, current video encryption methods usually integrate encryption algorithm with video compression course. This paper is devoted to discussing the video encryption technology, by encrypting to avoid unauthorized person getting video data. This paper studied the H.264 entropy coding and proposed of CAVLC video encryption scheme which is combined with the process of entropy coding of H.264 CAVLC encryption scheme. Three encryption levels are proposed. In addition, a scrambling method is also proposed which makes the encrypted frames more robust in anti crack. This method showed more robust video data encryption function and compressive rate.

A design of CAVLC(Context-Adaptive Variable Length Coding) for H.264 (H.264 CAVLC(Context-Adaptive Variable Length Coding)설계)

  • Lee, Yong-Ju;Suh, Ki-Bum
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2008.10a
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    • pp.108-111
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    • 2008
  • In this paper, we propose an advanced hardware architecture for the CAVLC entropy encoder engine for real time Full HD video compression. Since there are 384 data coefficients which are sum of 376 AC coefficient and 8 DC coefficient per one macroblock, 384 coefficient have to be processed per one macroblock in worst case for real time processing. We propose an novel architecture which includes parallel architecture and pipeline processing, and reduction "0" in AC/DC coefficient table. To verify the proposed architecture, we develop the reference C for CAVLC and verified the designed circuit with the test vector from reference C code.

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A VLSI Design and Implementation of a Single-Chip Encoder/Decoder with Dictionary Search Processor(DISP) using LZSS Algorithm and Entropy Coding (LZSS 알고리즘과 엔트로피 부호를 이용한 사전탐색처리장치를 갖는 부호기/복호기 단일-칩의 VLSI 설계 및 구현)

  • Kim, Jong-Seop;Jo, Sang-Bok
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.38 no.2
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    • pp.103-113
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    • 2001
  • This paper described a design and implementation of a single-chip encoder/decoder using the LZSS algorithm and entropy coding in 0.6${\mu}{\textrm}{m}$ CMOS technology. Dictionary storage for the dictionary search processor(DISP) used a 2K$\times$8bit on-chip memory with 50MHz clock speed. It performs compression on byte-oriented input data at a data rate of one byte per clock cycle except when one out of every 33 cycles is used to update the string window of dictionary. In result, the average compression ratio is 46% by applied entropy coding of the LZSS codeword output. This is to improved on the compression performance of 7% much more then LZSS.

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A New Motion Vector Coding Scheme for Improving Video Coding Efficiency (동영상 부호화 성능 개선을 위한 새로운 움직임 벡터 부호화 기법)

  • Ki, Dae-Wook;Kim, Hyun-Tae;Moon, Yong-Ho
    • The Journal of the Korea institute of electronic communication sciences
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    • v.8 no.5
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    • pp.659-664
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    • 2013
  • It is necessary to develop an efficient MVD coding scheme to improve the video coding performance. In this paper, combined codeword and joint codeword are suggested from analyses on statistical distributions of MVD according to the quantization steps and the conventional codeword structure. Based on these codewords, we propose new MVD coding scheme where one of the suggested codewords is employed to encode the MVD according to the coding environment. Simulation results show that the proposed scheme enhances the coding performance without the quality degradation.

An Efficient VLC Table Prediction Scheme for H.264 Using Weighting Multiple Reference Blocks (H.264 표준에서 가중된 다중 참조 블록을 이용한 효율적인 VLC 표 예측 방법)

  • Heo, Jin;Oh, Kwan-Jung;Ho, Yo-Sung
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.39-42
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    • 2005
  • H.264, a recently proposed international video coding standard, has adopted context-based adaptive variable length coding (CAVLC) as the entropy coding tool in the baseline profile. By combining an adaptive variable length coding technique with context modeling, we can achieve a high degree of redundancy reduction. However, CAVLC in H.264 has weakness that the correct prediction rate of the variable length coding (VLC) table is low in a complex area, such as the boundary of an object. In this paper, we propose a VLC table prediction scheme considering multiple reference blocks; the same position block of the previous frame and the neighboring blocks of the current frame. The proposed algorithm obtains the new weighting values considering correctness of the VLC table for each reference block. Using this method, we can enhance the prediction rate of the VLC table and reduce the bit-rate.

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Design of a Lossless Audio Coding Using Cholesky Decomposition and Golomb-Rice Coding (콜레스키 분해와 골롬-라이스 부호화를 이용한 무손실 오디오 부호화기 설계)

  • Cheong, Cheon-Dae;Shin, Jae-Ho
    • Journal of Korea Multimedia Society
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    • v.11 no.11
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    • pp.1480-1490
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    • 2008
  • Design of a linear predictor and matching of an entropy coder is the art of lossless audio coding. In this paper, we use the covariance method and the Choleskey decomposition for calculating linear prediction coefficients instead of the autocorreation method and the Levinson-Durbin recursion. These results are compared to the polynomial predictor. Both of them, the predictor which has small prediction error is selected. For the entropy coding, we use the Golomb-Rice coder using the block-based parameter estimation method and the sequential adaptation method with LOCO-land RLGR. The proposed predictor and the block-based parameter estimation have $2.2879%{\sim}0.3413%$ improved compression ratios compared to FLAC lossless audio coder which use the autocorrelation method and the Levinson-Durbin recursion. The proposed predictor and the LOCO-I adaptation method could improved by $2.2879%{\sim}0.3413%$. But the proposed predictor and the RLGR adaptation method got better results with specific signals.

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A Entropy Coding Method using Temporal and Spatial Correlation on HEVC (HEVC에서 시공간적 상관관계를 이용한 엔트로피 부호화 방법)

  • Kim, Tae-Ryong;Kim, Kyung-Yong;Lee, Han-Soo;Park, Gwang-Hoon
    • Journal of Broadcast Engineering
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    • v.17 no.1
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    • pp.191-194
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    • 2012
  • The split flag and the skip flag in CU syntax have high correlation on spatial domain as well as temporal domain. This paper suggests a method for enhancing coding efficiency by using not only spatial correlation but also temporal correlation when coding CU information. In the CABAC case, temporal collocated CU information is used for selecting context model of the split flag and the skip flag. In the CAVLC case, current CU information is estimated from temporal collocated CU information then encoded. As a result, a coding efficiency was increased by 0.1%~0.6% in CABAC, 0.1%~0.4% in CAVLC compared with HM 3.0. This method shows better performance on lowdelay condition which uses reference frame close to current frame.

Image Coding using Conditional Entropy Constrained Vector Quantization (조건부 엔트로피 제한 벡터 양자화를 이용한 영상 부호화)

  • Lee, Seung-Jun;Seo, Yong-Chang;Lee, Choong-Woong
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.11
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    • pp.88-96
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    • 1994
  • This paper proposes a new vector quantization scheme which exploits high correlations among indexes in vector quantization. An optimal vector quantizer in the rate-distortion sense can be obtained, if it is designed so that the average distortion can be minimized under the constraint of the conditional entropy of indes, which is usually much smaller than the entropy of index due to the high correlations among indexes of neighboring vectors. The oprimization process is very similar to that in ECVQ(entropy-constrained vector quanization) except that in the proposed scheme the Viterbi algorithm is introduced to find the optimal index sequence. Simulations show that at the same bitrate the proposed method provides higher PSNR by 1.0~3.0 dB than the conventional ECVQ when applied to image coding.

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