• Title/Summary/Keyword: H.264/AVC video

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An Effective of Rate Control for Scene Change in H.264/AVC (장면전환에 효율적인 H.264/AVC 비트율 제어 기법)

  • Son, Nam-Rye;Shin, Yoon-Jeong;Lee, Guee-Sang
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.44 no.1
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    • pp.26-39
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    • 2007
  • In recent years, rate control is an important technique in real time video communication applications using H.264/AVC. Many existing rate control algorithms employ the quadratic rate-distortion model, which is determine the target bits for each P frame. In this paper, a new rate control algorithm for transmission of H.264/AVC video bit stream through CBR(Constant Bit Rate) channel is proposed. The proposed algorithm predicts an adaptive QP(Quantization Parameter) for improving video distortion, due to high motion and abruptly scene change, which target bit rate and MAD(Mean of Absolute Difference) for current frame considering image complexity variance between previous and current frames. Additionally, it uses frame skip technique to maintain bit stream within a manageable range and protect buffer from overflow or underflow. Experimental results show that the proposed method gives a quality improvement of about 0.5dB when compared to previous rate control algorithm. Also our proposed algorithm encodes the video sequences with less frame skipping compared to the existing rate control for H.264/AVC.

Hybrid Interpolation using Intra Prediction Information of H.264/AVC (H.264/AVC의 인트라 예측 정보를 이용한 하이브리드 보간법)

  • Kwon, Yong-Kwang
    • Journal of the Korea Society of Computer and Information
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    • v.13 no.7
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    • pp.83-90
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    • 2008
  • EThe digitalized image information has various resolution, and it has been developed for several technologies to resize image depending on user's requests and applications. Recently the algorithm using edge information for good image/video quality on up-sampling was introduced, and the pre-processing procedure is required for edge extraction. Than, the predicted direction in intra prediction used in H.264/AVC has the similarity up to 80% for the edge information, so I propose the image up-sampling method using edge information. In proposed method, the image quality is similar to result of adapting n'th kernel. and the method reduces the number of calculation by about 50%.

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Real-time H.264/AVC High 4:4:4 Predictive Decoder Using Multi-Thread and SIMD Instructions (멀티쓰레드와 SIMD 명령어를 이용한 실시간 H.264/AVC High 4:4:4 Predictive 디코더의 구현)

  • Kim, Yong-Hwan;Kim, Je-Woo;Choi, Byeong-Ho;Lee, Seok-Pil;Paik, Joon-Ki
    • 한국정보통신설비학회:학술대회논문집
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    • 2007.08a
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    • pp.350-353
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    • 2007
  • This paper presents an real-time implementation of H.264/AVC High 4:4:4 Predictive profile decoder using general-purpose processors by exploiting multi-threading technique and Single Instruction Multiple Data (SIMD) instructions without any quality degradation. We analyze differences between the existing High profile and High 4:4:4 Predictive profile decoder, and show various optimization techniques to decode high fidelity and high definition (HD) video in real-time. Simulation results show that the proposed decoder can play high fidelity HD video at average 40 frames per seconds (fps) for the IBBrBP bistream and about 50 fps for the Intra-only bitstream.

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Efficient MPEG-4 to H.264/AVC Transcoding with Spatial Downscaling

  • Nguyen, Toan Dinh;Lee, Guee-Sang;Chang, June-Young;Cho, Han-Jin
    • ETRI Journal
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    • v.29 no.6
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    • pp.826-828
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    • 2007
  • Efficient downscaling in a transcoder is important when the output should be converted to a lower resolution video. In this letter, we suggest an efficient algorithm for transcoding from MPEG-4 SP (with simple profile) to H.264/AVC with spatial downscaling. First, target image blocks are classified into monotonous, complex, and very complex regions for fast mode decision. Second, adaptive search ranges are applied to these image classes for fast motion estimation in an H.264/AVC encoder with predicted motion vectors. Simulation results show that our transcoder considerably reduces transcoding time while video quality is kept almost optimal.

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Fast Intra Mode Selection Algorithm for H.264/AVC Using Constraints of Frequency Characteristics (주파수 특성의 제약 조건들을 이용한 H.264/AVC를 위한 고속 화면 내 모드 선택 방법)

  • Jin, Soon-Jong;Park, Sang-Jun;Jeong, Je-Chang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.4C
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    • pp.321-329
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    • 2008
  • H.264/AVC video coding standard enables a considerably higher improvement in coding efficiency compared with previous standards such as MPEG-2, H.263 and MPEG-4. To achieve this, for each macro-block in H.264/AVC, Rate-Distortion Optimization (RDO) technique is employed to select the best motion vector, reference frame, and macro-block mode. As a result, computational complexity is increased significantly whereas RDO achieve higher improvement. This paper presents fast intra mode selection algorithm based on constraints of frequency characteristics which are derived from intra coding modes of H.264/AVC. First of all, we observe the features of each intra mode through the frequency analysis of image. And then proposed Frequency Error Costs (FECs) are calculated to select the best mode which has minimum cost. Computational complexity is considerably reduced because rate-distortion costs only calculate the candidate modes which are set of best mode and its neighbouring two modes. Experimental results show that proposed algorithm reduces the complexity dramatically maintaining the rate-distortion performance compared with H.264/AVC reference software.

Fast intra mode decision using DCT coefficient distribution in H.264/AVC (H.264/AVC에서 DCT계수 분포를 이용한 고속 인트라 모드 결정 방법)

  • Hong, Sung-Wook;Lee, Yung-Lyul
    • Journal of Broadcast Engineering
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    • v.15 no.4
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    • pp.582-590
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    • 2010
  • he rate-distortion optimization (RDO) method in the H.264/AVC encoder is a technology that improves the coding efficiency, but increases the computational complexity. In this paper, a fast Intra mode decision algorithm using DCT (Discrete Cosine Transform) coefficients distribution is proposed to reduce the H.264 encoder complexity. The proposed method reduces the encoder complexity on average 68.40%, while the coding efficiency is slightly decreased compared with the H.264/AVC encoder.

Signature Extraction Method from H.264 Compressed Video (H.264/AVC로 압축된 비디오로부터 시그너쳐 추출방법)

  • Kim, Sung-Min;Kwon, Yong-Kwang;Won, Chee-Sun
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.3
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    • pp.10-17
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    • 2009
  • This paper proposes a compressed domain signature extraction method which can be used for CBCD (Content Based Copy Detection). Since existing signature extraction methods for the CBCD are executed in spatial domain, they need additional computations to decode the compressed video before the signature extraction. To avoid this overhead, we generate a thumbnail image directly from the compressed video without full decoding. Then we can extract the video signature from the thumbnail image. Experimental results of extracting brightness ordering information as the signature for CBCD show that our proposed method is 2.8 times faster than the spatial domain method while maintaining 80.98% accuracy.

An Efficient H.264/AVC Entropy Decoder Design (효율적인 H.264/AVC 엔트로피 복호기 설계)

  • Moon, Jeon-Hak;Lee, Seong-Soo
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.44 no.12
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    • pp.102-107
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    • 2007
  • This paper proposes a H.264/AVC entropy decoder without embedded processor nor memory fabrication process. Many researches on H.264/AVC entropy decoders require ROM or RAM fabrication process, which is difficult to be implemented in general digital logic fabrication process. Furthermore, many researches require embedded processors for bitstream manipulation, which increases area and power consumption. This papers proposes hardwired H.264/AVC entropy decoder without embedded processor, which improves data processing speed and reduces power consumption. Furthermore, its CAVLC decoder optimizes lookup table and internal buffer without embedded memory, which reduces hardware size and can be implemented in general digital logic fabrication process without ROM or RAM fabrication process. Designed entropy decoder was embedded in H.264/AVC video decoder, and it was verified to operate correctly in the system. Synthesized in TSMC 90nm fabrication process, its maximum operation frequency is 125MHz. It supports QCIF, CIF, and QVGA image format. Under slight modification of nC register and other blocks, it also support VGA image format.

A New Method for Thumbnail Extraction in H.264/AVC Bitstreams (H.264/AVC 비트스트림에서 썸네일 추출을 위한 새로운 방법)

  • Hong, Seung-Hwan;Kim, Ji-Eon;Chin, Young-Min;Kwon, Jae-Cheol;Oh, Seoung-Jun
    • Journal of Broadcast Engineering
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    • v.15 no.6
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    • pp.853-867
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    • 2010
  • Recently, thumbnail techniques are required to index a high-performance video at digital convergence-based multimedia service like IPTV and DMB. Therefore a thumbnail extraction method in H.264/AVC bitstreams has been proposed. However, thumbnail quality deterioration problem at converting the general equation of spatial domain to frequency domain which is generated by not considering about H.264/AVC transform and quantization processing and rounding-off operation in intra prediction. In this paper, we propose a new thumbnail extraction method in H.264/AVC bitstreams. The proposed scheme is based on H.264/AVC core-transform for a thumbnail extraction in frequency domain, and probability theory, intra rounding-off error compensation. Through the implementation and performance evaluation, the subjective quality difference between the output of our scheme and the output of reference decoder is negligible and better than the conventional method, and moreover PSNR gain by up to 8.66 dB.

Error Concealment Algorithm Using Lagrange Interpolation For H.264/AVC (RTP/IP 기반의 네트워크 전송 환경에서 라그랑제 보간법을 이용한 에러 은닉 기법)

  • Jung, Hak-Jae;Ahn, Do-Rang;Lee, Dong-Wook
    • Proceedings of the KIEE Conference
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    • 2005.05a
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    • pp.161-163
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    • 2005
  • In this paper, we propose an efficient motion vector recovery algorithm for the new coding standard H.264, which makes use of the Lagrange interpolation formula. In H.264/AVC, a 16$\times$16 macroblock can be divided into different block shapes for motion estimation, and each block has its own motion vector. In the natural video the motion vector is likely to move in the same direction, hence the neighboring motion vectors are correlative. Because the motion vector in H.264 covers smaller area than previous coding standards, the correlation between neighboring motion vectors increases. We can use the Lagrange interpolation formula to constitute a polynomial that describes the motion tendency of motion vectors, and use this polynomial to recover the lost motion vector. The simulation result shows that our algorithm can efficiently improve the visual quality of the corrupted video.

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