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Student Number 975203024
Author Run-yu Tong(童閏煜)
Author's Email Address rytong@vaplab.ce.ncu.edu.tw
Statistics This thesis had been viewed 545 times. Download 437 times.
Department Communication Engineering
Year 2009
Semester 2
Degree Master
Type of Document Master's Thesis
Language zh-TW.Big5 Chinese
Title Low Complexity Decoding in Parametric Stereo Audio Coding Scheme
Date of Defense 2010-07-07
Page Count 96
Keyword
  • decorrelation filter
  • Parametric Stereo
  • residual coding
  • spatial audio coding
  • spatial parameter
  • Abstract The Parametric Stereo (PS) audio coding is an audio coding object of High Efficiency Advanced Audio Coding version 2 (HE-AAC v2) which was standardized by ISO/MPEG in 2004. Traditional audio codec, e.g. MP3 or AAC, utilize “Psycoaustic Model” and “Masking Effect” to achieve high compression efficiency. However, they mainly process the signal with single channel. Different from traditional audio codec, the PS audio coding incorporates the characteristics of two channels, to extract spatial parameters and to down-mixes stereo signals into a mono signal. The PS can save almost half data size which provides great help in storage and transmission.
    Nevertheless, the complexity of PS decoder is nearly twice larger than that of PS encoder, which causes a serious problem in implementing PS on portable devices. Therefore, this thesis proposes a modified PS coding scheme to reduce the complexity of decoder. The encoder extracts and transmits the additional residual parameters from the residual signal and the mono signal. On the contrary, the decoder reconstructs the residual signal by the mono signal and the transmitted residual parameters. In addition, we detect the existence of transient signal and measure the artifact of reconstructed residual signal. Finally, “Energy compesated algorithm” is proposed to reduce the artifact produced by the transient signal.
    The proposed scheme can improve the Objective Difference Grade (ODG) of audio quality measurement “EAQUAL” with 0.6 score. Combining with audio coder AAC, the modified PS coding scheme still maintains a good performance at low coding bitrates.
    Table of Content 摘 要             I
    Abstract        II
    誌 謝            III
    目 錄            IV
    附圖索引               VI
    附表索引             VIII
    第一章緒論               1
    1.1研究背景               1
    1.2研究動機               2
    1.3論文架構             3
    第二章空間聽覺特徵與參數立體聲編解碼架構4
    2.1雙耳聽覺空間特徵參數     4
    2.1.1單音源音場:方向角定位特徵參數5
    2.1.2單音源音場:相似性特徵參數    7
    2.1.3雙音源音場        8
    2.2參數立體聲編碼架構        10
    2.2.1時域/頻域分析        10
    2.2.2特徵參數抽取及降混音    14
    2.3參數立體聲解碼架構        17
    2.3.1解相關濾波器        17
    2.3.2空間音場合成        21
    2.3.3複雜度分析與軟體實作考量    24
    2.4 冗餘訊號編解            35
    第三章參數立體音訊低複雜解碼方法    39
    3.1系統架構簡介        39
    3.2低複雜冗餘訊號重建        41
    3.2.1冗餘訊號特徵參數        41
    3.2.2冗餘訊號重建係數        42
    3.3暫態訊號能量補償        45
    3.3.1暫態訊號內插參數失真    45
    3.3.2暫態訊號能量補償演算法    49
    第四章實驗結果與討論        52
    4.1客觀音訊品質評量工具    52
    4.2複雜度-位元率-音訊品質探討    54
    4.3結合AAC編碼位元率與品質表現    74
    第五章結論與未來工作         80
    參考文獻
    Reference [1]Johnston and Ferreira, “Sum-Difference Stereo Transform Coding, ” Proc. ICASSP, pp.569- 571, May 1992
    [2]Chi-Min Liu, Wen-Chieh Lee, and Yo-Hua Hsiao, “M/S coding based on allocation entropy, ” Proc. of the 6th Int. Conference on Digital Audio Effects, London, UK, Sep. 11~18, 2003.
    [3]Lord Rayleigh (J.W. Strutt), “On our perception of sound direction,”
    Philosophical Magazine, 13:214–232, 1907.
    [4]C. Faller, “Parametric coding of spatial audio,” Proc. of the 7th International Conference on Digital Audio Effects (DAFx’04), Naples, Italy, October 5-8, 2004.
    [5]ISO/IEC JTC1/SC29/WG11, “Text of ISO/IEC 14496-3:2001/FPDAM2 (parametric coding for high quality audio),” ISO/IEC JTC1/SC29/WG11 N5713, July 2003.
    [6]E. Schuijers, J. Breebaart, H. Purnhagen, and J. Engdeg˙ard, “Low complexity parametric stereo coding,” in Proc. 116th AES Convention, Berlin, Germany, May 2004.
    [7]J. Hall and M. Fernandes, “The role of monaural frequency selectivity in binaural analysis,” in J. Acoust. Soc. Amer., 1984, vol. 76, pp. 435 – 439.
    [8]J. Engdegard, H. Purnhagen, J. Roden, and L. Liljeryd, “Sythetic ambience in parametric stereo coding,” in Proc. 116th AES Convention, Berlin, Germany, May 2004, pp.1-12.
    [9]M. R. Schroeder and B. F. Logan, “Colorless Artificial Reverberation”, J. Audio Eng. Soc., vol. 9, no. 3, pp. 192-197, July 1961.
    [10]J. Breebaart, S. van de Par, A. Kohlrausch, and E. Schuijers, “High-quality parametric spatial audio coding at low bitrates,” in Proc. 116th AES Convention, Berlin, Germany, May 2004.
    [11]R. Irwan and R. M. Aarts, “Two-to-five channel sound processing,” Journal of the Audio Engineering Society, vol. 50, no. 11, pp. 914–926, 2002.
    [12]T.C. Li, and P.C. Chang, “Spatial characteristic based scalable audio coding structure, “ in Proc. of National Symposium on Tele- communications (NST), Taipei, Taiwan, pp. 452-456, Dec. 2009.
    [13]J. Breebaart, S. van de Par, A. Kohlrausch, and E. Schuijers “Parametric coding of stereo audio”, EURASIP Journal, Applied Signal Processing 9:1305-1322, 2005.
    [14]J. Breebaart and C. Faller, Spatial Audio Processing, ed.1,WILEY, 2007,p82-84
    [15]ITU-R Recommendation BS.1387, Method for Objective Measurements of Perceived Audio Quality, Dec. 1998.
    Advisor
  • Pao-chi Chang(張寶基)
  • Files
  • 975203024.pdf
  • approve immediately
    Date of Submission 2010-07-26

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