Table of Contents

 1     Scope          
 2     General description of the coder     
        2.1     Encoder           
        2.2     Decoder           
        2.3     Delay 
        2.4     Speech coder description         
        2.5     Notational conventions             
 3     Functional description of the encoder           
        3.1     Preprocessing               
        3.2     Linear prediction analysis and quantization      
        3.3     Perceptual weighting 
        3.4     Open-loop pitch analysis          
        3.5     Computation of the impulse response               
        3.6     Computation of the target signal          
        3.7     Adaptive-codebook search     
        3.8     Fixed codebook – Structure and search             
        3.9     Quantization of the gains         
       3.10     Memory update         
 4     Functional description of the decoder           
        4.1     Parameter decoding procedure            
        4.2     Post-processing            
        4.3     Encoder and decoder initialization        
        4.4     Concealment of frame erasures            
 5     Bit-exact description of the CS-ACELP coder               
        5.1     Use of the simulation software             
        5.2     Organization of the simulation software            
 6     References               
Annex A – Reduced complexity 8 kbit/s CS-ACELP speech codec    
        A.1     Introduction  
        A.2     General description of the codec         
        A.3     Functional description of the encoder               
        A.4     Functional description of the decoder               
        A.5     Bit-exact description of the reduced complexity CS-ACELP codec          
Annex B – A silence compression scheme for ITU-T G.729 optimized for terminals conforming to ITU‑T V.70    
        B.1     Introduction  
        B.2     General description of the VAD/DTX/CNG algorithms 
        B.3     Detailed description of the VAD algorithm       
        B.4     Detailed description of the DTX/CNG algorithms           
        B.5     Bit-exact description of the silence compression scheme          
Annex C – Reference floating-point implementation for ITU-T G.729 CS-ACELP 8 kbit/s speech coding    
        C.1     Scope               
        C.2     Normative references               
        C.3     Overview        
        C.4     Algorithmic description             
        C.5     ANSI C code   
Annex C+ – Reference floating-point implementation for integrating ITU-T G.729  CS-ACELP speech coding main body with Annexes B, D and E    
       C+.1     Scope              
       C+.2     Normative references             
       C+.3     Overview      
       C+.4     New functionality      
       C+.5     Algorithm description              
       C+.6     Description of C source code
Annex D – +CS-ACELP speech coding algorithm at 6.4 kbit/s    
        D.1     Scope               
        D.2     Normative references              
        D.3     General coder description for the 6.4 kbit/s extension               
        D.4     Bit allocation  
        D.5     Functional description of the encoder               
        D.6     Functional description of decoder       
        D.7     ANSI C code   
Annex E – CS-ACELP speech coding algorithm at 11.8 kbit/s    
        E.1     Introduction   
        E.2     General description of the speech codec          
        E.3     Functional description of the encoder
        E.4     Functional description of the decoder
        E.5     Bit-exact description of the CS-ACELP coder    
Annex F – Reference implementation of ITU-T G.729 Annex B DTX functionality for Annex D    
        F.1     Scope
        F.2     Normative references               
        F.3     Overview        
        F.4     New functionality        
        F.5     Algorithm description
        F.6     Description of C source code  
Annex G – Reference implementation of Annex B DTX functionality for Annex E    

        G.1     Scope               
        G.2     Normative references              
        G.3     Overview       
        G.4     New functionality       
        G.5     Algorithm description               
        G.6     Description of C source code 
Annex H – Reference implementation of switching procedure between Annexes D and E    
        H.1     Scope               
        H.2     Normative references              
        H.3     Overview        
        H.4     Algorithm description
        H.5     Description of C source code  
Annex I – Reference fixed-point implementation for integrating ITU-T G.729 CS‑ACELP speech coding main body with Annexes B, D and E    
        I.1                   Scope   
        I.2                   Normative references  
        I.3                   Overview           
        I.4                   New functionality           
        I.5                   Algorithm description   
        I.6                   Description of C source code     
Annex J – An embedded variable bit-rate extension to ITU-T G.729: An interoperable 8‑32 kbit/s scalable wideband extension to ITU-T G.729    
Appendix I – External synchronous reset performance for ITU-T G.729 codecs in systems using external VAD/DTX/CNG    
        I.1                   Introduction      
        I.2                   Experimental design      
        I.3                   Performance observations         
        I.4                   Conclusion         
Appendix II – ITU-T G.729 Annex B enhancements in voice-over-IP applications –Option 1    
       II.1     Scope
       II.2     Abbreviations and acronyms   
       II.3     Introduction   
       II.4     Identified problems of ITU-T G.729B in VoIP applications           
       II.5     Experimental design   
       II.6     Electronic attachments              
Appendix III – Annex B enhancements in voice-over-IP applications – Option 2    
      III.1     Scope
      III.2     Solutions for the reported issues with Annex B              
      III.3     Examples for the solutions of reported issues with Annex B     
      III.4     Electronic attachments              
Appendix IV – Enhanced Voice Activity Detector    
       IV.1     Scope               
       IV.2     References    
       IV.3     Definitions     
       IV.4     Abbreviations and acronyms 
       IV.5     General description of enhanced VAD algorithm          
       IV.6     Detailed description of the enhanced VAD algorithm 
       IV.7     Organization and use of the simulation software