diff options
Diffstat (limited to 'protocols/Tlen/codec/gsm_long.c')
| -rw-r--r-- | protocols/Tlen/codec/gsm_long.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/protocols/Tlen/codec/gsm_long.c b/protocols/Tlen/codec/gsm_long.c new file mode 100644 index 0000000000..7d9148061c --- /dev/null +++ b/protocols/Tlen/codec/gsm_long.c @@ -0,0 +1,183 @@ +/*
+
+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.
+
+*/
+#include "gsm.h"
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+
+/* Decision levels */
+const static int gsm_DLB[4] = { 6554, 16384, 26214, 32767 };
+/* Quantization levels */
+const static int gsm_QLB[4] = { 3277, 11469, 21299, 32767 };
+
+/*
+ * Long term parameters calculation - lag (Nc) and gain (bc).
+ */
+static void longTermLTPCalculation(gsm_state *state, short *in, short *in_1)
+{
+ int k, lambda;
+ int Nc, bc;
+ float in_1_float_base[120], * in_1_float = in_1_float_base + 120;
+ float in_float[40];
+ float L_result, L_max, L_power;
+
+ for (k = -120; k < 0; k++) in_1_float[k] = (float)in_1[k];
+ for (k = 0; k < 40; k++) in_float[k] = (float)in[k];
+
+ /* Search for the maximum cross-correlation and coding of the LTP lag */
+
+ L_max = 0;
+ Nc = 40; /* index for the maximum cross-correlation */
+
+ for (lambda = 40; lambda < 121; lambda++) {
+ for (L_result = 0, L_power = 0, k = 0; k < 40; k++) {
+ L_result += in_float[k] * in_1_float[k - lambda];
+// L_power += in_1_float[k - lambda] * in_1_float[k - lambda];
+ }
+// L_result = L_result / L_power;
+ if (L_result > L_max) {
+ Nc = lambda;
+ L_max = L_result;
+ }
+ }
+ state->Nc[state->subframe] = Nc;
+ if (L_max <= 0.) {
+ state->bc[state->subframe] = 0;
+ return;
+ }
+ /* Compute the power of the reconstructed short term residual signal dp[..] */
+ in_1_float -= Nc;
+ L_power = 0;
+ for (k = 0; k < 40; k++) {
+ float f = in_1_float[k];
+ L_power += f * f;
+ }
+ if (L_max >= L_power) { //1.0
+ state->bc[state->subframe] = 3;
+ return;
+ }
+ /* Coding of the LTP gain
+ * Table gsm_DLB must be used to obtain the level DLB[i] for the
+ * quantization of the LTP gain b to get the coded version bc.
+ */
+// lambda = L_max * 32768.;
+ lambda = (int)(L_max * 32768. / L_power);
+ for (bc = 0; bc <= 2; ++bc) if (lambda <= gsm_DLB[bc]) break;
+ state->bc[state->subframe] = bc;
+}
+
+/*
+ * Here we decode the bc parameter and compute samples of the estimate out[0..39].
+ * The decoding of bc needs the gsm_QLB table.
+ * The long term residual signal e[0..39] is then calculated to be fed to the
+ * RPE encoding section.
+ */
+static void longTermAnalysisFilter(int Nc, int bc, short *in, short *in_1, short *out, int *e)
+{
+ int gain, k, l;
+ gain = gsm_QLB[bc];
+ for (k = 0; k < 40; k++) {
+ l = (gain * (int)in_1[k - Nc] + 16384) >> 15;
+ if (l < -32768) l = -32768;
+ else if (l > 32767) l = 32767;
+ out[k] = l;
+ e[k] = in[k] - l;
+ }
+}
+
+/*
+ * This procedure uses the bcr and Ncr parameter to realize the
+ * long term synthesis filtering. The decoding of bcr needs table gsm_QLB.
+ */
+static void longTermSynthesisFilter(gsm_state * state, int Ncr, int bcr, int *e, short *out)
+{
+ int k;
+ int brp, Nr;
+
+ /* Check the limits of Nr. */
+ Nr = Ncr < 40 || Ncr > 120 ? state->nrp : Ncr;
+ state->nrp = Nr;
+ /* Decoding of the LTP gain bcr */
+ brp = gsm_QLB[ bcr ];
+
+ /* Computation of the reconstructed short term residual
+ * signal drp[0..39]
+ */
+ for (k = 0; k < 40; k++) {
+ int temp = (brp * (int)out[ k-Nr ] + 16384) >> 15;
+ out[k] = e[k] + temp;
+ }
+}
+
+/*
+ * This procedure performs long term analysis.
+ */
+void longTermAnalysis(gsm_state *state, short *in)
+{
+ short *in_1 = state->dp0 + 120 + state->subframe * 40;
+ short *out = state->dp0 + 120 + state->subframe * 40;
+ int *e = state->e + state->subframe * 40;
+/*
+
+ int i;
+ printf("Long-term in: \n");
+ for (i=0;i<40;i++) {
+ printf("%7d ", in[i]);
+ }
+ printf("\n");
+ */
+ longTermLTPCalculation(state, in, in_1);
+ /* printf("Nc: %d, bc: %d \n", state->Nc[state->subframe], state->bc[state->subframe]);
+ */
+ longTermAnalysisFilter(state->Nc[state->subframe], state->bc[state->subframe], in, in_1, out, e);
+/*
+ printf("Long-term out: \n");
+ for (i=0;i<40;i++) {
+ printf("%7d ", out[i]);
+ }
+ printf("\n");
+ */
+}
+
+/*
+ * This procedure performs long term synthesis.
+ */
+void longTermSynthesis(gsm_state *state)
+{
+ int Nc = state->Nc[state->subframe];
+ int bc = state->bc[state->subframe];
+ int *e = state->e + state->subframe * 40;
+ short *out = state->dp0 + 120 + state->subframe * 40;
+ //int i;
+ longTermSynthesisFilter(state, Nc, bc, e, out);
+ /*
+ printf("Long-term reconstructed: \n");
+ for (i=0;i<160;i++) {
+ printf("%7d ", state->dp0[i]);
+ }
+ printf("\n");
+ */
+}
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