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Diffstat (limited to 'libs/libsndfile/src/GSM610/preprocess.c')
| -rw-r--r-- | libs/libsndfile/src/GSM610/preprocess.c | 115 |
1 files changed, 0 insertions, 115 deletions
diff --git a/libs/libsndfile/src/GSM610/preprocess.c b/libs/libsndfile/src/GSM610/preprocess.c deleted file mode 100644 index d1b473d693..0000000000 --- a/libs/libsndfile/src/GSM610/preprocess.c +++ /dev/null @@ -1,115 +0,0 @@ -/* - * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische - * Universitaet Berlin. See the accompanying file "COPYRIGHT" for - * details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE. - */ - -#include <stdio.h> -#include <assert.h> - -#include "gsm610_priv.h" - -#include "gsm.h" - -/* 4.2.0 .. 4.2.3 PREPROCESSING SECTION - * - * After A-law to linear conversion (or directly from the - * Ato D converter) the following scaling is assumed for - * input to the RPE-LTP algorithm: - * - * in: 0.1.....................12 - * S.v.v.v.v.v.v.v.v.v.v.v.v.*.*.* - * - * Where S is the sign bit, v a valid bit, and * a "don't care" bit. - * The original signal is called sop[..] - * - * out: 0.1................... 12 - * S.S.v.v.v.v.v.v.v.v.v.v.v.v.0.0 - */ - - -void Gsm_Preprocess ( - struct gsm_state * S, - word * s, - word * so ) /* [0..159] IN/OUT */ -{ - - word z1 = S->z1; - longword L_z2 = S->L_z2; - word mp = S->mp; - - word s1; - longword L_s2; - - longword L_temp; - - word msp, lsp; - word SO; - - register int k = 160; - - while (k--) { - - /* 4.2.1 Downscaling of the input signal - */ - SO = SASR_W( *s, 3 ) << 2; - s++; - - assert (SO >= -0x4000); /* downscaled by */ - assert (SO <= 0x3FFC); /* previous routine. */ - - - /* 4.2.2 Offset compensation - * - * This part implements a high-pass filter and requires extended - * arithmetic precision for the recursive part of this filter. - * The input of this procedure is the array so[0...159] and the - * output the array sof[ 0...159 ]. - */ - /* Compute the non-recursive part - */ - - s1 = SO - z1; /* s1 = gsm_sub( *so, z1 ); */ - z1 = SO; - - assert(s1 != MIN_WORD); - - /* Compute the recursive part - */ - L_s2 = s1; - L_s2 <<= 15; - - /* Execution of a 31 bv 16 bits multiplication - */ - - msp = SASR_L( L_z2, 15 ); - lsp = L_z2-((longword)msp<<15); /* gsm_L_sub(L_z2,(msp<<15)); */ - - L_s2 += GSM_MULT_R( lsp, 32735 ); - L_temp = (longword)msp * 32735; /* GSM_L_MULT(msp,32735) >> 1;*/ - L_z2 = GSM_L_ADD( L_temp, L_s2 ); - - /* Compute sof[k] with rounding - */ - L_temp = GSM_L_ADD( L_z2, 16384 ); - - /* 4.2.3 Preemphasis - */ - - msp = GSM_MULT_R( mp, -28180 ); - mp = SASR_L( L_temp, 15 ); - *so++ = GSM_ADD( mp, msp ); - } - - S->z1 = z1; - S->L_z2 = L_z2; - S->mp = mp; -} -/* -** Do not edit or modify anything in this comment block. -** The arch-tag line is a file identity tag for the GNU Arch -** revision control system. -** -** arch-tag: b760b0d9-3a05-4da3-9dc9-441ffb905d87 -*/ - |