1 Scope
2 Normative references
3 Definitions, symbols and abbreviations
3.1 Definitions
3.2 Symbols
3.3 Abbreviations
4 Outline description
4.1 Functional description of audio parts
4.2 Preparation of speech samples
4.3 Principles of the adaptive multirate wideband speech encoder
4.4 Principles of the adaptive multirate speech decoder
4.5 Sequence and subjective importance of encoded parameters
5 Functional description of the encoder
5.1 Preprocessing
5.2 Linear prediction analysis and quantization
5.2.1 Windowing and
autocorrelation computation
5.2.2
Levinson‑Durbin algorithm
5.2.3 LP to ISP
conversion
5.2.4 ISP to LP
conversion
5.2.5 Quantization of
the ISP coefficients
5.2.6 Interpolation of
the ISPs
5.3 Perceptual weighting
5.4 Open‑loop pitch analysis
5.4.1 6.60 kbit/s
mode
5.4.2 8.85, 12.65,
14.25, 15.85, 18.25, 19.85, 23.05 and 23.85 kbit/s modes
5.5 Impulse
response computation
5.6 Target
signal computation
5.7 Adaptive codebook
5.8 Algebraic codebook
5.8.1 Codebook
structure
5.8.2 Pulse indexing
5.8.3 Codebook search
5.9 Quantization of the adaptive and fixed codebook gains
5.10 Memory update
5.11 High-band gain generation
6 Functional description of the decoder
6.1 Decoding and speech synthesis
6.2 High-pass filtering, up-scaling and interpolation
6.3 High frequency band
6.3.1 Generation of
high-band excitation
6.3.2 LP filter for the
high frequency band
6.3.3 High band
synthesis
7 Detailed bit allocation of the adaptive multi-rate wideband codec
8 Homing sequences
8.1 Functional description
8.2 Definitions
8.3 Encoder homing
8.4 Decoder homing
9 Voice Activity Detector (VAD)
9.1 VAD Symbols
9.1.1 VAD Variables
9.1.2 VAD Constants
9.1.3 Functions
9.2 Functional description
9.2.1 Filter bank and
computation of sub-band levels
9.2.2 Tone detection
9.2.3 VAD decision
10 Bibliography