FreeCalypso > hg > gsm-codec-lib
view libtwamr/syn_filt.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 | 2af94ba0c075 |
children |
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/* ******************************************************************************** * * GSM AMR-NB speech codec R98 Version 7.6.0 December 12, 2001 * R99 Version 3.3.0 * REL-4 Version 4.1.0 * ******************************************************************************** * * File : syn_filt.c * Purpose : Perform synthesis filtering through 1/A(z). * ******************************************************************************** */ /* ******************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ******************************************************************************** */ #include "namespace.h" #include "syn_filt.h" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "typedef.h" #include "basic_op.h" #include "no_count.h" #include "cnst.h" /* ******************************************************************************** * LOCAL VARIABLES AND TABLES ******************************************************************************** */ /* *--------------------------------------* * Constants (defined in cnst.h * *--------------------------------------* * M : LPC order * *--------------------------------------* */ /* ******************************************************************************** * PUBLIC PROGRAM CODE ******************************************************************************** */ void Syn_filt ( Word16 a[], /* (i) : a[M+1] prediction coefficients (M=10) */ Word16 x[], /* (i) : input signal */ Word16 y[], /* (o) : output signal */ Word16 lg, /* (i) : size of filtering */ Word16 mem[], /* (i/o) : memory associated with this filtering. */ Word16 update /* (i) : 0=no update, 1=update of memory. */ ) { Word16 i, j; Word32 s; Word16 tmp[80]; /* This is usually done by memory allocation (lg+M) */ Word16 *yy; /* Copy mem[] to yy[] */ yy = tmp; move16 (); for (i = 0; i < M; i++) { *yy++ = mem[i]; move16 (); } /* Do the filtering. */ for (i = 0; i < lg; i++) { s = L_mult (x[i], a[0]); for (j = 1; j <= M; j++) { s = L_msu (s, a[j], yy[-j]); } s = L_shl (s, 3); *yy++ = round (s); move16 (); } for (i = 0; i < lg; i++) { y[i] = tmp[i + M]; move16 (); } /* Update of memory if update==1 */ test (); if (update != 0) { for (i = 0; i < M; i++) { mem[i] = y[lg - M + i]; move16 (); } } return; }