• Title, Summary, Keyword: 비트율 제어

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Selective Quality Control of Multiple Video Programs for Digital Broadcasting Service (디지털 방송 서비스를 위한 다수의 비디오 프로그램들의 선택적 화질 제어)

  • 홍성훈;유상조
    • Journal of Broadcast Engineering
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    • v.6 no.2
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    • pp.148-159
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    • 2001
  • This paper presents a selective duality control system to control relative picture quality among the video programs in terms of Peak Signal-to-Noise Ratio (PSNR) . The selective quality control system allows variable bit rate (VBR) for each video program to maintain the pre-determitted relative picture Quality among aggregated video programs while keeping a constant bit rate for alt programs to be transmitted over a single constant bit rate (CBR) channel. Thus is achieved by simultaneous controlling the video encoders to generate VBR video streams at the central controller. furthermore, we also suggest a buffer regulation method based on the analysis of the constraints Imposed by sender/receiver buffer sizes and the total transmission rate. Through various simulation results, it is found that the proposed quality control system guarantees that the video buffers neither overflow nor underflow and the quality control errors do not exceed 0.1 dB.

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An Adaptive Rate Control Using Piecewise Linear Approximation Model (부분 선형 근사 모델을 이용한 적응적 비트율 제어)

  • 조창형;정제창;최병욱
    • Journal of Broadcast Engineering
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    • v.2 no.2
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    • pp.194-205
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    • 1997
  • In video compression standards such as MPEG and H.263. rate control is one of the key components for good coding performance. This paper presents a simple adaptive rate control scheme using a piecewise linear approximation model. While conventional buffer control approach is performed by adjusting the quantization parameter linearly according to the buffer fullness. the proposed approach uses a piecewise linear approximation model derived from logarithmic relation between the quantization parameter and bitrate in data compression. In addition. a forward analyzer performed in the spatial domain is used to improve image quality. Simulation results demonstrate that the proposed method provides better performance than the conventional one and reduces the fluctuation of the PSNR per frame while maintaining the quality of the reconstructed frames at a relatively stable level.

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A Self-Organizing Model Based Rate Control Algorithm for MPEG-4 Video Coding

  • Zhang, Zhi-Ming;Chang, Seung-Gi;Park, Jeong-Hoon;Kim, Yong-Je
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.40 no.1
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    • pp.72-78
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    • 2003
  • A new self-organizing neuro-fuzzy network based rate control algorithm for MPEG-4 video encoder is proposed in this paper. Contrary to the traditional methods that construct the rate-distorion (RD) model based on experimental equations, the proposed method effectively exploits the non-stationary property of the video date with neuro-fuzzy network that self-organizes the RD model online and adaptively updates the structure. The method needs not require off-line pre-training; hence it is geared toward real-time coding. The comparative results through the experiments suggest that our proposed rate control scheme encodes the video sequences with less frame skip, providing good temporal quality and higher PSNR, compared to VM18.0.

MPEG-4 Rate Control Method with Spatio-Temporal Trade-Offs (시공간 화질의 절충을 고려한 MPEG-4 비트율 제어 알고리즘)

  • Lee Jeong-Woo;Ho Yo-Sung
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.41 no.1
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    • pp.47-56
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    • 2004
  • This paper describes a new bit allocation algorithm that can achieve a constant bit rate when coding multiple video objects, while improving rate-distortion (R-D) performance over the VM5 method for MPEG-4 object-based video coding. In particular, we propose two models to estimate the rate-distortion characteristics of coded objects as well as skipped objects. Based on the proposed models, we present several R-D coding modes with spatio-temporal trade-offs to improve coding efficiency. The proposed algorithm is performed at the object level for object-based video coding. Simulation results demonstrate moderate improvement at low as well as high bit rates. The proposed algorithm can produce the actual coded bits very close to the target bits over a wide range of bit rates. Consequently, the proposed algerian has not experienced any buffer overflow or underflow over the bit rates between 32 kbps and 256 kbps.

Rate Control based on linear relation for H.264/MPEG-4 AVC (선형 관계를 이용한 H.264/MPEG-4 AVC 비트율 제어 방법)

  • Na Hyeong-Youl;Lim Sung-Chang;Lee Yung-Lyul
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.43 no.1
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    • pp.27-38
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    • 2006
  • The main purpose of rate control is to achieve the highest video quality when bandwidth or storage capacity is limited. For this purpose, we need a rate control algorithm which is adaptively controlled by the motion information of sequences, scene change, buffer capacity and time-varing bandwitdh channels. A rate-control method in the encoder requires the accurate estimation of target bit for each frame and the low end-to-end delay for transmitting video data by intelligent selection of encoding parameters. In this paper, we suggest three kinds of linear relation in the encoder to satisfy the characteristics of rate control. The first relation is that between the percentage of zero quantized transformed coefficients(p) and coded bits. Second relation is that between the PSNR of encoded frame and its Quantization parameter(QP). Finally, we can find out a linear approximation between QP and p. According to the experimental analysis, the proposed method results in an efficient rate control in terms of the bit estimation, the buffer capacity, and PSNR compared with the existing rate control in the H.264 JM 9.3.

A Rate Control Algorithm for the H.264 Video Coding Standard (H.264 비디오 부호화 표준을 위한 비트율 제어 알고리즘)

  • Kim Seon-Ki;Ho Yo-Sung
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.11-15
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    • 2003
  • 비디오 부호화기에서는 채널의 용량과 같은 주어진 제약 조건을 만족하면서 좋은 화질을 얻기 위해 비디오 부호화 시 적절한 양자화 변수를 결정해야 한다. 본 논문에서는 H.264 비디오 부호화 표준에서 높은 압축 효율을 철기 위해 비트 율 왜곡 모델에 기반 한 새로운 비트 율 제어 알고리즘을 제안한다. 특히. 부호화된 매크로블록의 특성과 이전에 부호화 된 매크로 발생 비트수를 고려하여. 제안한 비트 율 모델을 통해 양자화 변수 값을 결정한다. 본 논문에서 제안한 알고리즘은 목표 비트수에 가깝고. 기존치 방법보다 개선된 화질을 제공한다.

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Hardware Design of Rate Control for H.264/AVC Real-Time Video Encoding (실시간 영상 부호화를 위한 H.264/AVC의 비트율 제어 하드웨어 설계)

  • Kim, Changho;Ryoo, Kwangki
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.12
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    • pp.201-208
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    • 2012
  • In this paper, the hardware design of rate control for real-time video encoded is proposed. In the proposed method, a quadratic rate distortion model with high-computational complexity is not used when quantization parameter values are being decided. Instead, for low-computational complexity, average complexity weight values of frames are used to calculate QP. For high speed and low computational prediction, the MAD is predicted based on the coded basic unit, using spacial and temporal correlation in sequences. The rate control is designed with the hardware for fast QP decision. In the proposed method, a quadratic rate distortion model with high-computational complexity is not used when quantization parameter values are being decided. Instead, for low-computational complexity, average complexity weight values of frames are used to calculate QP. In addition, the rate control is designed with the hardware for fast QP decision. The execution cycle and gate count of the proposed architecture were reduced about 65% and 85% respectively compared with those of previous architecture. The proposed RC was implemented using Verilog HDL and synthesized with UMC $0.18{\mu}m$ standard cell library. The synthesis result shows that the gate count of the architecture is about 19.1k with 108MHz clock frequency.

Research of QoS Control for Standardization on Real-time Multimedia Service Using MAC/PHY Feedback (MAC/PHY 정보를 이용한 실시간 멀티미디어 서비스의 QoS 제어 방식의 표준화를 위한 연구)

  • Kim, Min-Geon;Kim, Jun-Oh;Suh, Doug-Young
    • Journal of Broadcast Engineering
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    • v.16 no.5
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    • pp.738-749
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    • 2011
  • In this paper, we study QoS(Quality of Service) control protocols and the effect using MAC/PHY parameters of client device in mobile network. We proposes the way of controling the bit-rate by estimating the channel condition of the client with measured MAC/PHY parameters which is sent from the client. With the proposed method, more accurate available bit-rate can be estimated compared to conventional protocol, RTCP(Real-time Transport Control Protocol). The accurate bit-rate estimation can decrease wasted bit-rate and transport delay. In the result of the advantages, the transported video quality can be enhanced. In this paper, we show the effects of enhancement using client's the field data measured in WiMAX.

A rate control scheme using a new rate model for the HEVC video codec (새로운 율모델을 이용한 HEVC 율제어 기법)

  • Lee, Bumshik;Kim, Munchurl
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.358-360
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    • 2012
  • 본 논문에서는 새로운 율모델을 기반으로한 프레임 단위 HEVC 율제어 기법을 제안한다. 기존의 비디오 압축표준과는 달리 HEVC 는 계층 구조를 지닌 쿼드트리 기반 움직임 예측 및 변환 부호화를 수행한다. 본 논문에서는 쿼드트리 계층의 깊이에 따라 신호의 통계적 특성이 매우 달라지는 것은 이용하여 라플라시안 확률 모델을 각 쿼드트리 계층에 독립적으로 이용한 새로운 율모델을 이용한 율제어 기법을 제안한다. 제안방법에서는 계층적 부호화 단위인 CU 를 계층 깊이에 따라 세 가지 카테고리로 분류하고 각 카테고리에 따라 변환 계수에 대한 라플라시안 확률 분포 함수를 율-양자화 모델을 만든다. 제안된 율모델은 특성이 매우 다른 각 CU 깊이에 따라 독립적인 라플라이안 확률 분포 함수를 이용하기 때문에 매우 정확하고 적응적인 비트율 예측이 가능하므로 보다 안정적이고 정확한 율제어가 가능하다. 실험결과는 제안된 율제어 기법이 단일 확률 분포 함수를 사용했을 경우보다 평균 0.16dB 의 PSNR 향상이 있었음을 보여주었으며 제안된 방법은 각 프레임에 대한 목표 비트에 보다 안정적으로 부호화하는 것을 보여주었다.

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Enhanced Frame-Layer Rate Control for High-motion Low-bit rate Video in H.264 (저 비트율 영상에 대한 향상된 H.264 프레임 단위 데이터율 제어 알고리즘)

  • Lee, Chang-Hyun;Lee, Won-Jae;Kim, Jae-Seok
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.44 no.6
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    • pp.77-82
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    • 2007
  • In the existing frame-layer rate control for H.264, buffer status and content complexity are used improperly, causing quality fluctuations of high-motion video at low bit rates and high frame rates (under 19.2 kbps at 30 fps). We propose an enhanced H.264 frame-layer rate control scheme to obtain steady video quality and stable buffer management. Experimental results showed that the proposed scheme performed better than existing schemes.