Annex I Frame
or packet loss concealment for the LD-CELP decoder
I.1 Scope
I.2 Normative references
I.3 Introduction
I.4 Principles of operation
I.4.1 Excitation extrapolation
I.4.2 LPC filter
I.4.3 Backward adaptation of LPC and gain
predictors
I.4.4 Post-filter
I.4.5 Limitation of gain growth after frame
erasure
I.5 Pseudo-code for frame erasure concealment
I.5.1 New main program loop for decoder
I.5.2 Block 31SF Set flags and scaling
factor for frame erasure
I.5.3 Block 31FE Excitation signal
extrapolation
I.5.4
Block 31E Excitation signal update
I.5.5 Block 43FE Hybrid windowing module
I.5.6 Block 47AF Log-gain limiter after
frame erasure
I.5.7 Block 49FE Hybrid window module
for synthesis filter
I.5.8 Block 51FE Bandwidth
expansion module for frame erasures
I.5.9 Block 97FE Update GSTATE
during frame erasures
I.5.10 Block 98AF Log-gain limiter after
frame erasure
I.6 Additional coder parameters and variables
Appendix I.I Values used for scaling ETPAST during
frame erasures