CONTENTS
1 Introduction
1.1 Scope
1.2 Bit rates
1.3 Possible input signals
1.4 Delay
1.5 Speech coder description
2 Encoder
principles
2.1 General
description
2.2 Framer
2.3 High pass filter
2.4 LPC
analysis
2.5 LSP
quantizer
2.6 LSP
decoder
2.7 LSP
interpolation
2.8 Formant
perceptual weighting filter
2.9 Pitch
estimation
2.10 Subframe
processing
2.11 Harmonic
noise shaping
2.12 Impulse
response calculator
2.13 Zero input
response and ringing subtraction
2.14 Pitch
predictor
2.15 High rate
excitation (MP-MLQ)
2.16 Low rate
excitation (ACELP)
2.17 Excitation
decoder
2.18 Decoding of
the pitch information
2.19 Memory
update
2.20 Bit
allocation
2.21 Coder
initialization
3 Decoder
principles
3.1 General
description
3.2 LSP
decoder
3.3 LSP
interpolator
3.4 Decoding
of the pitch
information
3.5
Excitation
decoder
3.6 Pitch
postfilter
3.7 LPC
synthesis filter
3.8 Formant
postfilter
3.9 Gain
scaling unit
3.10 Frame
interpolation handling
3.11 Decoder
initialization
4 Bitstream
packing
5 ANSI C code
6 Glossary
Annex A – Silence compression scheme
A.1
Introduction
A.2
Description of the VAD
A.3 General
description of the CNG
A.4
Description of the CNG encoder part
A.5
Description of the decoder part
A.6 Bit
stream packing
A.7
Glossary
A.8
Bit-exact, fixed-point C source code
Annex B – Alternative specification based on floating point
arithmetic
B.1
Introduction
B.2
Algorithm description
B.3 ANSI C
code
Annex C – Scalable channel coding scheme for
wireless applications
C.1
Introduction
C.2 Channel
encoder
C.3 Channel
decoder
C.4 Fixed
point C source code