FreeCalypso > hg > gsm-codec-lib
view libgsmefr/residu.c @ 477:4c9222d95647
libtwamr encoder: always emit frame->mode = mode;
In the original implementation of amr_encode_frame(), the 'mode' member
of the output struct was set to 0xFF if the output frame type is TX_NO_DATA.
This design was made to mimic the mode field (16-bit word) being set to
0xFFFF (or -1) in 3GPP test sequence format - but nothing actually depends
on this struct member being set in any way, and amr_frame_to_tseq()
generates the needed 0xFFFF on its own, based on frame->type being equal
to TX_NO_DATA.
It is simpler and more efficient to always set frame->mode to the actual
encoding mode in amr_encode_frame(), and this new behavior has already
been documented in doc/AMR-library-API description in anticipation of
the present change.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Sat, 18 May 2024 22:30:42 +0000 |
parents | de9dc80c1312 |
children |
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/************************************************************************* * * FUNCTION: Residu * * PURPOSE: Computes the LP residual. * * DESCRIPTION: * The LP residual is computed by filtering the input speech through * the LP inverse filter A(z). * *************************************************************************/ #include "gsm_efr.h" #include "typedef.h" #include "namespace.h" #include "basic_op.h" #include "no_count.h" #include "sig_proc.h" /* m = LPC order == 10 */ #define m 10 void Residu ( Word16 a[], /* (i) : prediction coefficients */ Word16 x[], /* (i) : speech signal */ Word16 y[], /* (o) : residual signal */ Word16 lg /* (i) : size of filtering */ ) { Word16 i, j; Word32 s; for (i = 0; i < lg; i++) { s = L_mult (x[i], a[0]); for (j = 1; j <= m; j++) { s = L_mac (s, a[j], x[i - j]); } s = L_shl (s, 3); y[i] = round (s); move16 (); } return; }