diff options
Diffstat (limited to 'plugins/!NotAdopted/Tlen/codec/gsm_lpc.c')
| -rw-r--r-- | plugins/!NotAdopted/Tlen/codec/gsm_lpc.c | 208 |
1 files changed, 0 insertions, 208 deletions
diff --git a/plugins/!NotAdopted/Tlen/codec/gsm_lpc.c b/plugins/!NotAdopted/Tlen/codec/gsm_lpc.c deleted file mode 100644 index 519612baff..0000000000 --- a/plugins/!NotAdopted/Tlen/codec/gsm_lpc.c +++ /dev/null @@ -1,208 +0,0 @@ -/*
-
-Tlen Protocol Plugin for Miranda IM
-Copyright (C) 2004-2007 Piotr Piastucki
-
-This program is based on GSM 06.10 source code developed by
-Jutta Degener and Carsten Bormann,
-Copyright 1992, 1993, 1994 by Jutta Degener and Carsten Bormann,
-Technische Universitaet Berlin
-
-This program is free software; you can redistribute it and/or
-modify it under the terms of the GNU General Public License
-as published by the Free Software Foundation; either version 2
-of the License, or (at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program; if not, write to the Free Software
-Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
-
-*/
-
-/* LPC- and Reflection Coefficients
- * The next two functions calculate linear prediction coefficients
- * and/or the related reflection coefficients from the first P_MAX+1
- * values of the autocorrelation function.
- */
-#include "gsm.h" /* for P_MAX */
-#include <math.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-/* Compute the autocorrelation
- * ,--,
- * ac(l) = > x(i) * x(i-l) for all i
- * `--'
- * for lags l between 0 and lag-1, and x(i) == 0 for i < 0 or i >= n
- * @param n: number of samples
- * @param lax: max lag (order)
- * @param in: [0...n-1] samples x
- * @param out: [0...lag-1] autocorrelation
- */
-static void autocorrelation(int n, float const *x, int lag, float *ac)
-{
- float d;
- int i, j;
- for (j = 0; j < lag; j++) {
- for (i = j, d = 0; i < n; i++) d += x[i] * x[i-j];
- ac[j] = d;
- }
- d = (float)fabs(ac[0]);
- if (d != 0) {
- for (j = 0; j < lag; j++) ac[j] /= d;
- }
-}
-
-/* The Levinson-Durbin algorithm was invented by N. Levinson in 1947
- * and modified by J. Durbin in 1959.
- * @param in: [0...p] autocorrelation values
- * @param out: [0...p-1] reflection coefficients
- * @param lpc: [0...p-1] LPC coefficients
- * @return minimum mean square error
- */
-/*
-static float levinson_durbin (float const *ac, float *ref, float *lpc)
-{
- int i, j;
- float r, error = ac[0];
-
- if (ac[0] == 0) {
- for (i = 0; i < P_MAX; i++) ref[i] = 0;
- return 0;
- }
-
- for (i = 0; i < P_MAX; i++) {
-
- r = -ac[i + 1];
- for (j = 0; j < i; j++) r -= lpc[j] * ac[i - j];
- ref[i] = r /= error;
-
- // Update LPC coefficients and total error.
- lpc[i] = r;
- for (j = 0; j < i / 2; j++) {
- float tmp = lpc[j];
- lpc[j] = r * lpc[i - 1 - j];
- lpc[i - 1 - j] += r * tmp;
- }
- if (i % 2) lpc[j] += lpc[j] * r;
-
- error *= 1 - r * r;
- }
- return error;
-}
-*/
-/* I. Schur's recursion from 1917 is related to the Levinson-Durbin method,
- * but faster on parallel architectures; where Levinson-Durbin would take time
- * proportional to p * log(p), Schur only requires time proportional to p. The
- * GSM coder uses an integer version of the Schur recursion.
- * @param in: [0...p] autocorrelation values
- * @param out: [0...p-1] reflection coefficients
- * @return the minimum mean square error
- */
-static float schur(float const *ac, float *ref)
-{
- int i, m;
- float error=ac[0], r, G[2][P_MAX];
-
- if (ac[0] == 0.0) {
- for (i = 0; i < P_MAX; i++) ref[i] = 0;
- return 0;
- }
-
- /* Initialize the rows of the generator matrix G to ac[1...p]. */
- for (i = 0; i < P_MAX; i++) G[0][i] = G[1][i] = ac[i + 1];
-
- for (i = 0;;) {
- /* Calculate this iteration's reflection coefficient and error. */
- ref[i] = r = -G[1][0] / error;
- error += G[1][0] * r;
-
- if (++i >= P_MAX) return error;
-
- /* Update the generator matrix. Unlike Levinson-Durbin's summing of
- * reflection coefficients, this loop could be executed in parallel
- * by p processors in constant time.
- */
- for (m = 0; m < P_MAX - i; m++) {
- G[1][m] = G[1][m + 1] + r * G[0][m];
- G[0][m] = G[1][m + 1] * r + G[0][m];
- }
- }
-}
-
-
- /* 0..7 IN/OUT */
-static void rToLAR(int *r)
-/*
- * The following scaling for r[..] and LAR[..] has been used:
- *
- * r[..] = integer( real_r[..]*32768. ); -1 <= real_r < 1.
- * LAR[..] = integer( real_LAR[..] * 16384 );
- * with -1.625 <= real_LAR <= 1.625
- */
-{
- int temp;
- int i;
-
- /* Computation of the LAR[0..7] from the r[0..7]
- */
- for (i = 0; i < 8; i++) {
- temp = abs(r[i]); //GSM_ABS(temp);
- if (temp < 22118) {
- temp >>= 1;
- } else if (temp < 31130) {
- temp -= 11059;
- } else {
- temp -= 26112;
- temp <<= 2;
- }
- r[i] = r[i] < 0 ? -temp : temp;
- }
-}
-
-static void quantizeLARs(int *LARs, int *qLARs)
-{ int qA[]={20480, 20480, 20480, 20480, 13964, 15360, 8534, 9036};
- int qB[]={0, 0, 2048, -2560, 94, -1792, -341, -1144};
- int qMin[]={-32, -32, -16, -16, -8, -8, -4, -4};
- int qMax[]={31, 31, 15, 15, 7, 7, 3, 3};
- int i;
- for (i = 0; i < 8; i++) {
- int temp;
- temp = (((LARs[i] * qA[i]) >> 15) + qB[i] + 256) >> 9;
- if (temp < qMin[i]) temp = 0;
- else if (temp > qMax[i]) temp = qMax[i] - qMin[i];
- else temp = temp - qMin[i];
- qLARs[i] = temp;
- }
-}
-
-void lpcAnalysis(gsm_state *state, short *in)
-{ float error;
- float samples[160];
- float ac[9];
- float ref[8];
- int i;
- int * qLARs = state->qLARs;
- for (i = 0; i < 160; i++) {
- samples[i] = in[i];
- }
- autocorrelation(160, samples, 9, ac);
- error=schur(ac, ref);
- /*
- printf("reff: ");
- for (i=0;i<8;i++) {
- printf("%5.5f ", ref[i]);//((float)i_lpc[i])/32768.0f);
- }
- printf("\n");
- */
- for (i = 0; i < 8; i++) {
- qLARs[i] = (int) (32768 * ref[i]);
- }
- rToLAR(qLARs);
- quantizeLARs(qLARs, qLARs);
-}
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