• Title/Summary/Keyword: Predictive Vector Quantizer

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A LSF Quantizer for the Wideband Speech Using the Predictive VQ-Pyramid VQ (예측 VQ-Pyramid VQ를 이용한 광대역 음성용 LSF 양자학기 설계)

  • 이강은;이인성;강상원
    • The Journal of the Acoustical Society of Korea
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    • v.23 no.4
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    • pp.333-339
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    • 2004
  • This Paper proposes the vector quantizer-pyramid vector quantizer(VQ-PVQ) structure. Also both predictive structure and safety-net concept are combined into the VQ-PVQ to quantize the IPC parameter of wideband speech codec. The Performance is compared to the LPC vector quantizer used in the AMR-WB(ITU-T G.722.2). demonstrating reduction in both spectral distortion and encoding memory.

Block Constrained Trellis Coded Vector Quantization of LSF Parameters for Wideband Speech Codecs

  • Park, Jung-Eun;Kang, Sang-Won
    • ETRI Journal
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    • v.30 no.5
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    • pp.738-740
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    • 2008
  • In this paper, block constrained trellis coded vector quantization (BC-TCVQ) is presented for quantizing the line spectrum frequency parameters of the wideband speech codec. Both a predictive structure and a safety-net concept are combined into BC-TCVQ to develop the predictive BC-TCVQ. The performance of this quantization is compared with that of the linear predictive coding vector quantizer used in the AMRWB codec, demonstrating reductions in spectral distortion.

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Design of the LSF Parameter Quantizer for the Wideband Speech Codec (광대역 음성 부호화기용 선 스펙트럼 주파수 계수 양자화기 설계)

  • 지상현;강상원;윤병식
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.4
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    • pp.29-34
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    • 2001
  • In this paper, we designed an LSF coefficient quantizer of the wideband speech codec that can produce high quality speech service. For the efficient LSF coefficient quantizer, the interframe correlation was used. Also we separately quantized the LSF coefficients with high and low interframe correlation. Predictive pyramid vector quantizer (PVQ) was used for quantizing the LSF coefficients with high interframe correlation, and PVQ was used for quantizing the LSF coefficients with low interframe correlation. Experiments show that the proposed UF quantizer can quantize LSF information in 40 bits/frame, with an average spectral distortion (SD) of 1 dB and less than 3.87% frames having SD greater than 2 dB.

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A Study of BWE-Prediction-Based Split-Band Coding Scheme (BWE 예측기반 대역분할 부호화기에 대한 연구)

  • Song, Geun-Bae;Kim, Austin
    • The Journal of the Acoustical Society of Korea
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    • v.27 no.6
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    • pp.309-318
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    • 2008
  • In this paper, we discuss a method for efficiently coding the high-band signal in the split-band coding approach where an input signal is divided into two bands and then each band may be encoded separately. Generally, and especially through the research on the artificial bandwidth extension (BWE), it is well known that there is a correlation between the two bands to some degree. Therefore, some coding gain could be achieved by utilizing the correlation. In the BWE-prediction-based coding approach, using a simple linear BWE function may not yield optimal results because the correlation has a non-linear characteristic. In this paper, we investigate the new coding scheme more in details. A few representative BWE functions including linear and non-linear ones are investigated and compared to find a suitable one for the coding purpose. In addition, it is also discussed whether there are some additional gains in combining the BWE coder with the predictive vector quantizer which exploits the temporal correlation.

Adaptive coding algorithm using quantizer vector codebook in HDTV (양자화기 벡터 코드북을 이용한 HDTV 영상 적응 부호화)

  • 김익환;최진수;박광춘;박길흠;하영호
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.10
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    • pp.130-139
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    • 1994
  • Video compression algorithms are based on removing spatial and/or temproal redundancy inherent in image sequences by predictive(DPCM) encoding, transform encoding, or a combination of predictive and transform encoding. In this paper, each 8$\times$8 DCT coefficient of DFD(displaced frame difference) is adaptively quantized by one of the four quantizers depending on total distortion level, which is determined by characteristics of HVS(human visual system) and buffer status. Therefore, the number of possible quantizer selection vectors(patterns) is 4$^{64}$. If this vectors are coded, toomany bits are required. Thus, the quantizer selection vectors are limited to 2048 for Y and 512 for each U, V by the proposed method using SWAD(sum of weighted absolute difference) for discriminating vectors. The computer simulation results, using the codebook vectors which are made by the proposed method, show that the subjective and objective image quality (PSNR) are goor with the limited bit allocation. (17Mbps)

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Statistical Error Compensation Techniques for Spectral Quantization

  • Choi, Seung-Ho;Kim, Hong-Kook
    • Speech Sciences
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    • v.11 no.4
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    • pp.17-28
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    • 2004
  • In this paper, we propose a statistical approach to improve the performance of spectral quantization of speech coders. The proposed techniques compensate for the distortion in a decoded line spectrum pairs (LSP) vector based on a statistical mapping function between a decoded LSP vector and its corresponding original LSP vector. We first develop two codebook-based probabilistic matching (CBPM) methods based on linear mapping functions according to different assumption of distribution of LSP vectors. In addition, we propose an iterative procedure for the two CBPMs. We apply the proposed techniques to a predictive vector quantizer used for the IS-641 speech coder. The experimental results show that the proposed techniques reduce average spectral distortion by around 0.064dB.

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Implementation of Voice Codec using APC Algorithm for INMARSAT-B (APC(Adaptive Predictive Coder) 알고리즘을 응용한 INMARSAT-B Voice Codec구현)

  • Lee, Chae-Ho;Hwang, Yun-Ho;Kim, Jeong-Hun;Lim, Jong-Kun;Bae, Jung-Chul;Choi, Woo-Jin;Lee, Joon-Tark
    • Proceedings of the KIEE Conference
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    • 1999.07g
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    • pp.3246-3248
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    • 1999
  • The APC is a coding algorithm which has the middle property of both Wave Coding(ex ADPCM) and Vocoding(ex CELP) and can decode a proper quality of sound by using scalar quantizer instead of vector quantizer at computation a low calculation. So, the APC required for Voice Codec of INMARSAT-B could be successfully implemented by full duplex using TMS32OC30(DSP).

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