| Benny Prijono | a4bf021 | 2006-02-10 15:57:08 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische |
| 3 | * Universitaet Berlin. See the accompanying file "COPYRIGHT" for |
| 4 | * details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE. |
| 5 | */ |
| 6 | |
| 7 | /* $Header: /tmp_amd/presto/export/kbs/jutta/src/gsm/RCS/code.c,v 1.3 1996/07/02 09:59:05 jutta Exp $ */ |
| 8 | |
| 9 | #include "config.h" |
| 10 | |
| 11 | |
| 12 | #ifdef HAS_STDLIB_H |
| 13 | #include <stdlib.h> |
| 14 | #else |
| 15 | # include "proto.h" |
| 16 | extern char * memcpy P((char *, char *, int)); |
| 17 | #endif |
| 18 |
|
| 19 | #ifdef HAS_STRING_H
|
| 20 | #include <string.h>
|
| 21 | #endif
|
| 22 | |
| 23 | #include "private.h" |
| 24 | #include "gsm.h" |
| 25 | #include "proto.h" |
| 26 | |
| 27 | /* |
| 28 | * 4.2 FIXED POINT IMPLEMENTATION OF THE RPE-LTP CODER |
| 29 | */ |
| 30 | |
| 31 | void Gsm_Coder P8((S,s,LARc,Nc,bc,Mc,xmaxc,xMc), |
| 32 | |
| 33 | struct gsm_state * S, |
| 34 | |
| 35 | word * s, /* [0..159] samples IN */ |
| 36 | |
| 37 | /* |
| 38 | * The RPE-LTD coder works on a frame by frame basis. The length of |
| 39 | * the frame is equal to 160 samples. Some computations are done |
| 40 | * once per frame to produce at the output of the coder the |
| 41 | * LARc[1..8] parameters which are the coded LAR coefficients and |
| 42 | * also to realize the inverse filtering operation for the entire |
| 43 | * frame (160 samples of signal d[0..159]). These parts produce at |
| 44 | * the output of the coder: |
| 45 | */ |
| 46 | |
| 47 | word * LARc, /* [0..7] LAR coefficients OUT */ |
| 48 | |
| 49 | /* |
| 50 | * Procedure 4.2.11 to 4.2.18 are to be executed four times per |
| 51 | * frame. That means once for each sub-segment RPE-LTP analysis of |
| 52 | * 40 samples. These parts produce at the output of the coder: |
| 53 | */ |
| 54 | |
| 55 | word * Nc, /* [0..3] LTP lag OUT */ |
| 56 | word * bc, /* [0..3] coded LTP gain OUT */ |
| 57 | word * Mc, /* [0..3] RPE grid selection OUT */ |
| 58 | word * xmaxc,/* [0..3] Coded maximum amplitude OUT */ |
| 59 | word * xMc /* [13*4] normalized RPE samples OUT */ |
| 60 | ) |
| 61 | { |
| 62 | int k; |
| 63 | word * dp = S->dp0 + 120; /* [ -120...-1 ] */ |
| 64 | word * dpp = dp; /* [ 0...39 ] */ |
| 65 | |
| 66 | static word e[50]; |
| 67 | |
| 68 | word so[160]; |
| 69 | |
| 70 | Gsm_Preprocess (S, s, so); |
| 71 | Gsm_LPC_Analysis (S, so, LARc); |
| 72 | Gsm_Short_Term_Analysis_Filter (S, LARc, so); |
| 73 | |
| 74 | for (k = 0; k <= 3; k++, xMc += 13) { |
| 75 | |
| 76 | Gsm_Long_Term_Predictor ( S, |
| 77 | so+k*40, /* d [0..39] IN */ |
| 78 | dp, /* dp [-120..-1] IN */ |
| 79 | e + 5, /* e [0..39] OUT */ |
| 80 | dpp, /* dpp [0..39] OUT */ |
| 81 | Nc++, |
| 82 | bc++); |
| 83 | |
| 84 | Gsm_RPE_Encoding ( S, |
| 85 | e + 5, /* e ][0..39][ IN/OUT */ |
| 86 | xmaxc++, Mc++, xMc ); |
| 87 | /* |
| 88 | * Gsm_Update_of_reconstructed_short_time_residual_signal |
| 89 | * ( dpp, e + 5, dp ); |
| 90 | */ |
| 91 | |
| 92 | { register int i; |
| 93 | register longword ltmp; |
| 94 | for (i = 0; i <= 39; i++) |
| 95 | dp[ i ] = GSM_ADD( e[5 + i], dpp[i] ); |
| 96 | } |
| 97 | dp += 40; |
| 98 | dpp += 40; |
| 99 | |
| 100 | } |
| 101 | (void)memcpy( (char *)S->dp0, (char *)(S->dp0 + 160), |
| 102 | 120 * sizeof(*S->dp0) ); |
| 103 | } |