FreeCalypso > hg > gsm-codec-lib
view libgsmefr/preemph.c @ 411:bd5614fc780a
libtwamr: integrate VAD2 lflg_upd.c
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Tue, 07 May 2024 01:18:25 +0000 |
parents | 9aef9e54b19d |
children |
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/*---------------------------------------------------------------------* * routine preemphasis() * * ~~~~~~~~~~~~~~~~~~~~~ * * Preemphasis: filtering through 1 - g z^-1 * *---------------------------------------------------------------------*/ #include "gsm_efr.h" #include "typedef.h" #include "namespace.h" #include "basic_op.h" #include "no_count.h" #include "sig_proc.h" #include "cnst.h" #include "dec_state.h" void preemphasis ( struct EFR_decoder_state *st, Word16 *signal, /* (i/o) : input signal overwritten by the output */ Word16 g, /* (i) : preemphasis coefficient */ Word16 L /* (i) : size of filtering */ ) { Word16 *p1, *p2, temp, i; p1 = signal + L - 1; p2 = p1 - 1; temp = *p1; for (i = 0; i <= L - 2; i++) { *p1 = sub (*p1, mult (g, *p2--)); p1--; } *p1 = sub (*p1, mult (g, st->mem_pre)); st->mem_pre = temp; return; }