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comparison libgsmfr2/dec_main.c @ 266:8821ffaa93a5

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libgsmfr2: integrate decoder main function from libgsm
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 14 Apr 2024 00:36:16 +0000
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265:a7b593e68ac3 266:8821ffaa93a5
1 /*
2 * This C source file has been adapted from TU-Berlin libgsm source
3 * (src/decode.c), original notice follows:
4 *
5 * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
6 * Universitaet Berlin. See the accompanying file "COPYRIGHT" for
7 * details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
8 */
9
10 #include <stdint.h>
11 #include "tw_gsmfr.h"
12 #include "typedef.h"
13 #include "ed_state.h"
14 #include "ed_internal.h"
15
16 /*
17 * 4.3 FIXED POINT IMPLEMENTATION OF THE RPE-LTP DECODER
18 */
19
20 static void Postprocessing (
21 struct gsmfr_0610_state * S,
22 register word * s)
23 {
24 register int k;
25 register word msr = S->msr;
26 register longword ltmp; /* for GSM_ADD */
27 register word tmp;
28
29 for (k = 160; k--; s++) {
30 tmp = GSM_MULT_R( msr, 28180 );
31 msr = GSM_ADD(*s, tmp); /* Deemphasis */
32 *s = GSM_ADD(msr, msr) & 0xFFF8; /* Truncation & Upscaling */
33 }
34 S->msr = msr;
35 }
36
37 void gsmfr_0610_decode_params(struct gsmfr_0610_state *S,
38 const struct gsmfr_param_frame *inp, int16_t *s)
39 {
40 int j, k;
41 word erp[40], wt[160];
42 word * drp = S->dp0 + 120;
43
44 for (j=0; j <= 3; j++) {
45 Gsm_RPE_Decoding(S, inp->xmaxc[j], inp->Mc[j], inp->xMc[j],
46 erp);
47 Gsm_Long_Term_Synthesis_Filtering(S, inp->Nc[j], inp->bc[j],
48 erp, drp);
49
50 for (k = 0; k <= 39; k++) wt[ j * 40 + k ] = drp[ k ];
51 }
52
53 Gsm_Short_Term_Synthesis_Filter(S, inp->LARc, wt, s);
54 Postprocessing(S, s);
55 }