G.729語(yǔ)音編解碼算法及其在DSP上的實(shí)現(xiàn)
頁(yè)數(shù) 39 字?jǐn)?shù) 21653


摘 要

多媒體技術(shù)的不斷發(fā)展，對(duì)語(yǔ)音編碼提出的要求也越來(lái)越高。不僅要求低碼率、低延時(shí)，而且要求很高的語(yǔ)音質(zhì)量。而作為中低速率語(yǔ)音編碼算法中的佼佼者G.729越來(lái)越受到廣泛的重視。
ITU-T G.729語(yǔ)音編碼方案采用共軛結(jié)構(gòu)代數(shù)碼本激勵(lì)線性預(yù)測(cè)技術(shù)（CS-ACELP），算法具有8Kbit/s的編碼速率、較低的延遲和高編碼語(yǔ)音質(zhì)量。它在會(huì)議電視、數(shù)字綜合業(yè)務(wù)網(wǎng)、網(wǎng)絡(luò)多媒體通信和語(yǔ)音存儲(chǔ)系統(tǒng)等領(lǐng)域得到廣泛的應(yīng)用。近年來(lái)，高速數(shù)字信號(hào)處理器的發(fā)展使G.729這類高復(fù)雜的編解碼器的實(shí)現(xiàn)成了可能。
　本文在介紹了語(yǔ)音編碼的基礎(chǔ)上，詳細(xì)分析了CS－ACELP語(yǔ)音編碼算法原理及其特性。運(yùn)用標(biāo)準(zhǔn)C語(yǔ)音按照結(jié)構(gòu)化設(shè)計(jì)方法實(shí)現(xiàn)了算法的仿真，并用標(biāo)準(zhǔn)的測(cè)試序列對(duì)仿真程序進(jìn)行了測(cè)試，驗(yàn)證了其正確性。 在此基礎(chǔ)上，基于TI　TMS320C6711　DSP硬件平臺(tái)，實(shí)現(xiàn)了對(duì)語(yǔ)音信號(hào)的編解碼。合成語(yǔ)音信號(hào)經(jīng)過(guò)主觀測(cè)試，語(yǔ)音質(zhì)量良好，滿足通信要求。

關(guān)鍵詞：語(yǔ)音編碼，語(yǔ)音解碼，CS－ACELP，G.729，DSP


Abstract

With the improvement of the multimedia communication technology, common users now ask for more and more convenience for speech coding. Not only bit rate and low delay but also high quality speech coding schemes are needed.As a good arithmetic of low speed speech coding arithmetic, G729 is regarded extensively.
ITU-T G.729 speech coding protocol ,which adopted the Conjungate-Structure Algebraic-Code-Excited Linear-Prediction (CS-ACELP)technology.It has the performance of codin rate of 8Kbit/s,low delay and high reconstructed speech quality. It is widely used in video telephony,B-ISDN,network multimedia systems and digital speech storage systems,etc. Due to the develpment of DSPs chips,it is now possible for us to process the speech signals with complicated algorithms such as G.729.
In this thesis,after introducing the principle of speech coding,the principle and characteristic of CS-ACELP are analysed in detail. With the computer language ANSI-C employed,CS-ACELP is realized using the structured design method.Validity of the simulator is justified with the standard test vectors.And then,speech coding and decoding are realized at the base of TI TMS320C6711 DSP chip.The reconstructed speech is proved high quality ,and meet the requirement in telecommunication.


Key words: Speech coding Speech decoding CS-ACELP G.729 DSP







目 錄

中文摘要..................................................................1
ABSTRACT...............................................................2
第一章　引言..............................................................1
1.1　課題來(lái)源與選題依據(jù).................................................1
1.2　課題研究的意義與價(jià)值...............................................1
1.3　研究?jī)?nèi)容與論文結(jié)構(gòu).................................................2
第二章　語(yǔ)音編碼理論基礎(chǔ)..................................................2
2.1　語(yǔ)音信號(hào)的產(chǎn)生模型與特點(diǎn)...........................................3
2.2　語(yǔ)音編碼的分類與比較...............................................4
2.3　語(yǔ)音編碼中常用的處理技術(shù)...........................................5
　　2.3.1 短時(shí)分析技術(shù)....................................................5　
2.3.2 線性預(yù)測(cè)編碼（LPC）分析.........................................6　
2.3.3 矢量量化........................................................6　
2.3.4 碼本激勵(lì)線性預(yù)測(cè)................................................7　
第三章　CS－ACELP語(yǔ)音編解碼算法分析....................................8
3.1　CS－ACELP算法概述..................................................8
3.2　CS－ACELP語(yǔ)音編碼原理.............................................10
　　3.2.1 預(yù)處理.........................................................10
3.2.2 LP分析、量化、內(nèi)插.............................................10
3.2.3 感知加權(quán)........................................................12　
3.2.4 基音分析........................................................13　
3.2.5 固定碼本結(jié)構(gòu)及其搜索............................................15　
3.2.6 增益量化........................................................16
3.3　CS－ACELP語(yǔ)音解碼原理..............................................17
　　3.3.1 參數(shù)解碼........................................................17　
3.3.2 重構(gòu)語(yǔ)音信號(hào)....................................................18　
3.3.3 后置濾波器......................................................18　
3.3.4 錯(cuò)誤幀屏蔽處理..................................................20　
第四章　TMS320C6711仿真開(kāi)發(fā)系統(tǒng)........................................20
4.1　TMS3206711DSK硬件平臺(tái)..............................................21
4.2　DSP軟件仿真平臺(tái)....................................................22
第五章　G.729語(yǔ)音編解碼標(biāo)準(zhǔn)在TMS320C6711仿真開(kāi)發(fā)系統(tǒng)上的實(shí)現(xiàn)
.............................24
5.1　G.729標(biāo)準(zhǔn)算法C程序的實(shí)現(xiàn)..........................................24
　　5.1.1 編碼部分........................................................25　
5.1.2 解碼部分........................................................26　
5.2　G.729標(biāo)準(zhǔn)在TMS320C6711上的實(shí)現(xiàn)....................................28
　　5.2.1 語(yǔ)音壓縮解壓回放系統(tǒng)的硬件設(shè)計(jì)...................................28　
5.2.2　語(yǔ)音壓縮解壓回放系統(tǒng)的軟件設(shè)計(jì)　................................29　
　　5.2.3 系統(tǒng)實(shí)現(xiàn)的調(diào)試與測(cè)試............................................31　
總結(jié) ......................................................................32
致謝 ......................................................................33
參考文獻(xiàn) ..................................................................34


參　考　文　獻(xiàn)

[1] ITU-T Recommendation G.729:Coding of Speech at 8Kbits/s Using Conjugate Structure Algebraic Code Excited Linear Prediction(CS-ACELP),1996.3　
[2] 楊行俊，遲惠生.《 數(shù)字語(yǔ)音信號(hào)處理》 電子工業(yè)出版社，1995
[3]　趙力 　《語(yǔ)音信號(hào)處理》　機(jī)械工業(yè)出版社，2003
[4] TI（Texas Instruments）公司 《TMS320C6000 Code Composer Studio Help》
[5]　李方慧，王飛，何佩琨　《TMS320C6000系列DSPs原理與應(yīng)用》　電子工業(yè)出版社，2003