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 G.729 optimized for terminals conforming to ITU‑T Recommendation 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 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 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       
        E.6     Bibliography          
Annex F – Reference implementation of 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 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 G.729: An interoperable 8‑32 kbit/s scalable wideband extension to G.729    
Appendix I – External synchronous reset performance for 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 – 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 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