Version 0.3.2 from FTP

git-svn-id: http://svn.digium.com/svn/zaptel/trunk@124 5390a7c7-147a-4af0-8ec9-7488f05a26cb

1 files changed, 389 insertions, 0 deletions

diff --git a/mec2.h b/mec2.h
new file mode 100755
index 0000000..36bc042
--- /dev/null
+++ b/mec2.h
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+/*
+ * Mark's Second Echo Canceller
+ * 
+ * Copyright (C) 2002, Digium, Inc.
+ *
+ * This program is free software and may be used and
+ * distributed according to the terms of the GNU
+ * General Public License, incorporated herein by
+ * reference.
+ *
+ */
+#ifndef _MARK2_ECHO_H
+#define _MARK2_ECHO_H
+
+#ifdef __KERNEL__
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#define MALLOC(a) kmalloc((a), GFP_KERNEL)
+#define FREE(a) kfree(a)
+#else
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <string.h>
+#include <math.h>
+#define MALLOC(a) malloc(a)
+#define FREE(a) free(a)
+#endif
+
+/* Get optimized routines for math */
+#include "arith.h"
+
+#ifndef NULL
+#define NULL 0
+#endif
+#ifndef FALSE
+#define FALSE 0
+#endif
+#ifndef TRUE
+#define TRUE (!FALSE)
+#endif
+
+#include "mec2_const.h"
+
+/* Circular buffer definition */
+typedef struct {
+  int idx_d;
+  int size_d;
+  short *buf_d;	/* Twice as large as we need */
+} echo_can_cb_s;
+
+// class definition
+//
+typedef struct  {
+  /* Echo canceller definition */
+
+  /* absolute time */
+  int i_d;
+  
+  /* pre-computed constants */
+
+  int N_d;
+  int beta2_i;
+
+  // declare accumulators for power computations
+  //
+  int Ly_i;
+  int Lu_i;
+
+  // declare an accumulator for the near-end signal detector
+  //
+  int s_tilde_i;
+  int HCNTR_d;
+
+  // circular buffers and coefficients
+  //
+  int *a_i;
+  short *a_s;
+  echo_can_cb_s y_s;
+  echo_can_cb_s s_s;
+  echo_can_cb_s u_s;
+  echo_can_cb_s y_tilde_s;
+  int y_tilde_i;
+
+  /* Max memory */
+  short max_y_tilde;
+  int max_y_tilde_pos;
+
+} echo_can_state_t;
+
+static inline void init_cb_s(echo_can_cb_s *cb, int len, void *where)
+{
+	cb->buf_d = (short *)where;
+	cb->idx_d = 0;
+	cb->size_d = len;
+}
+
+static inline void add_cc_s(echo_can_cb_s *cb, short newval)
+{
+    /* Can't use modulus because N+M isn't a power of two (generally) */
+    cb->idx_d--;
+    if (cb->idx_d < (int)0)
+     {cb->idx_d += cb->size_d;}
+	/* Load two copies into memory */
+	cb->buf_d[cb->idx_d] = newval;
+	cb->buf_d[cb->idx_d + cb->size_d] = newval;
+}
+
+static inline short get_cc_s(echo_can_cb_s *cb, int pos)
+{
+	/* Load two copies into memory */
+	return cb->buf_d[cb->idx_d + pos];
+}
+
+static inline void init_cc(echo_can_state_t *ec, int N, int maxy, int maxu) {
+
+  void *ptr = ec;
+  unsigned long tmp;
+  /* double-word align past end of state */
+  ptr += sizeof(echo_can_state_t);
+  tmp = (unsigned long)ptr;
+  tmp += 3;
+  tmp &= ~3L;
+  ptr = (void *)tmp;
+  
+  // reset parameters
+  //
+  ec->N_d = N;
+  ec->beta2_i = DEFAULT_BETA1_I;
+  
+  // allocate coefficient memory
+  //
+  ec->a_i = ptr;
+  ptr += (sizeof(int) * ec->N_d);
+  ec->a_s = ptr;
+  ptr += (sizeof(short) * ec->N_d);
+
+  /* Reset Y circular buffer (short version) */
+  init_cb_s(&ec->y_s, maxy, ptr);
+  ptr += (sizeof(short) * (maxy) * 2);
+  
+  /* Reset Sig circular buffer (short version for FIR filter) */
+  init_cb_s(&ec->s_s, (1 << DEFAULT_ALPHA_ST_I), ptr);
+  ptr += (sizeof(short) * (1 << DEFAULT_ALPHA_ST_I) * 2);
+
+  init_cb_s(&ec->u_s, maxu, ptr);
+  ptr += (sizeof(short) * maxu * 2);
+
+  // allocate a buffer for the reference signal power computation
+  //
+  init_cb_s(&ec->y_tilde_s, ec->N_d, ptr);
+
+
+  // reset absolute time
+  //
+  ec->i_d = (int)0;
+  
+  // reset the power computations (for y and u)
+  //
+  ec->Ly_i = DEFAULT_CUTOFF_I;
+
+  // reset the near-end speech detector
+  //
+  ec->s_tilde_i = 0;
+  ec->HCNTR_d = (int)0;
+
+  // exit gracefully
+  //
+}
+
+static inline void echo_can_free(echo_can_state_t *ec)
+{
+	FREE(ec);
+}
+
+static inline short echo_can_update(echo_can_state_t *ec, short iref, short isig) {
+
+  /* declare local variables that are used more than once
+  */
+  int k;
+  int rs;
+  short u;
+  int Py_i;
+  int two_beta_i;
+  
+  /***************************************************************************
+  //
+  // flow A on pg. 428
+  //
+   ***************************************************************************/
+
+  /* eq. (16): high-pass filter the input to generate the next value;
+  //           push the current value into the circular buffer
+  //
+  // sdc_im1_d = sdc_d;
+  // sdc_d = sig;
+  //  s_i_d = sdc_d;
+  //  s_d = s_i_d;
+  //  s_i_d = (float)(1.0 - gamma_d) * s_i_d
+     + (float)(0.5 * (1.0 - gamma_d)) * (sdc_d - sdc_im1_d); */
+  
+  
+  /* Delete last sample from power estimate */
+  ec->y_tilde_i -= abs(get_cc_s(&ec->y_s, (1 << DEFAULT_ALPHA_YT_I) - 1 )) >> DEFAULT_ALPHA_YT_I;
+  /* push the reference data onto the circular buffer */
+  add_cc_s(&ec->y_s, iref);
+ 
+  /* eq. (2): compute r in fixed-point */
+  rs = CONVOLVE2(ec->a_s, ec->y_s.buf_d + ec->y_s.idx_d, ec->N_d);
+  rs >>= 15;
+
+  /* eq. (3): compute the output value (see figure 3) and the error
+  // note: the error is the same as the output signal when near-end
+  // speech is not present
+  */
+  u = isig - rs;  
+  
+  add_cc_s(&ec->u_s, u);
+  
+
+
+  /* Delete oldest part of received s_tilde */
+  ec->s_tilde_i -= abs(get_cc_s(&ec->s_s, (1 << DEFAULT_ALPHA_ST_I) - 1 ));
+
+  /* push the signal on the circular buffer, too */
+  add_cc_s(&ec->s_s, isig);
+  ec->s_tilde_i += abs(isig);
+  ec->y_tilde_i += abs(iref) >> DEFAULT_ALPHA_ST_I;
+
+  /* Add to our list of recent y_tilde's */
+  add_cc_s(&ec->y_tilde_s, ec->y_tilde_i);		
+
+  /****************************************************************************
+  //
+  // flow B on pg. 428
+  // 
+   ****************************************************************************/
+  
+  /* compute the new convergence factor
+  */
+  Py_i = (ec->Ly_i >> DEFAULT_SIGMA_LY_I) * (ec->Ly_i >> DEFAULT_SIGMA_LY_I);
+  Py_i >>= 15;
+  if (ec->HCNTR_d > 0) {
+  	Py_i = (1 << 15);
+  }
+  
+#if 0
+  printf("Py: %e, Py_i: %e\n", Py, Py_i * AMPL_SCALE_1);
+#endif  
+
+  /* Vary rate of adaptation depending on position in the file
+  // Do not do this for the first (DEFAULT_UPDATE_TIME) secs after speech
+  // has begun of the file to allow the echo cancellor to estimate the
+  // channel accurately
+  */
+#if 0
+  if (ec->start_speech_d != 0 ){
+    if ( ec->i_d > (DEFAULT_T0 + ec->start_speech_d)*(SAMPLE_FREQ) ){
+      ec->beta2_d = max_cc_float(MIN_BETA,
+		       DEFAULT_BETA1 * exp((-1/DEFAULT_TAU)*((ec->i_d/(float)SAMPLE_FREQ) -
+						 DEFAULT_T0 -
+						 ec->start_speech_d)));
+    }
+  }
+  else {ec->beta2_d = DEFAULT_BETA1;}
+#endif
+  
+  ec->beta2_i = DEFAULT_BETA1_I;	/* Fixed point, inverted */
+  
+  two_beta_i = (ec->beta2_i * Py_i) >> 15;	/* Fixed point version, inverted */
+  if (!two_beta_i)
+  	two_beta_i++;
+
+  /* Update Lu_i (Suppressed power estimate) */
+  ec->Lu_i -= abs(get_cc_s(&ec->u_s, (1 << DEFAULT_SIGMA_LU_I) - 1 )) ;
+  ec->Lu_i += abs(u);
+
+  /* eq. (10): update power estimate of the reference
+  */
+  ec->Ly_i -= abs(get_cc_s(&ec->y_s, (1 << DEFAULT_SIGMA_LY_I) - 1)) ;
+  ec->Ly_i += abs(iref);
+
+  if (ec->Ly_i < DEFAULT_CUTOFF_I)
+  	ec->Ly_i = DEFAULT_CUTOFF_I;
+
+#if 0
+  printf("Float: %e, Int: %e\n", ec->Ly_d, (ec->Ly_i >> DEFAULT_SIGMA_LY_I) * AMPL_SCALE_1);
+#endif
+  
+  if (ec->y_tilde_i > ec->max_y_tilde) {
+  	/* New highest y_tilde with full life */
+	ec->max_y_tilde = ec->y_tilde_i;
+	ec->max_y_tilde_pos = ec->N_d - 1;
+  } else if (--ec->max_y_tilde_pos < 0) {
+    /* Time to find new max y tilde... */
+	ec->max_y_tilde = MAX16(ec->y_tilde_s.buf_d + ec->y_tilde_s.idx_d, ec->N_d, &ec->max_y_tilde_pos);
+  }
+
+  if ((ec->s_tilde_i >> (DEFAULT_ALPHA_ST_I - 1)) > ec->max_y_tilde)
+    {
+      ec->HCNTR_d = DEFAULT_HANGT;
+    }
+  else if (ec->HCNTR_d > (int)0)
+    {
+      ec->HCNTR_d--;
+    }
+
+  /* update coefficients if no near-end speech and we have enough signal
+   * to bother trying to update.
+  */
+  if (!ec->HCNTR_d && !(ec->i_d % DEFAULT_M) && 
+      (ec->Lu_i > MIN_UPDATE_THRESH_I)) {
+	    // loop over all filter coefficients
+	    //
+	    for (k=0; k<ec->N_d; k++) {
+	      
+	      // eq. (7): compute an expectation over M_d samples 
+	      //
+		  int grad2;
+	      grad2 = CONVOLVE2(ec->u_s.buf_d + ec->u_s.idx_d,
+		  					ec->y_s.buf_d + ec->y_s.idx_d + k, DEFAULT_M);
+	      // eq. (7): update the coefficient
+	      //
+	      ec->a_i[k] += grad2 / two_beta_i;
+		  ec->a_s[k] = ec->a_i[k] >> 16;
+	    }
+  }
+
+  /* paragraph below eq. (15): if no near-end speech,
+  // check for residual error suppression
+  */
+#ifndef NO_ECHO_SUPPRESSOR
+  if ((ec->HCNTR_d == 0) && ((ec->Ly_i/(ec->Lu_i + 1)) > DEFAULT_SUPPR_I)) {
+  	u = u * (ec->Lu_i >> DEFAULT_SIGMA_LU_I) / ((ec->Ly_i >> (DEFAULT_SIGMA_LY_I + 2)) + 1);
+  }
+#endif  
+
+#if 0
+  if ((ec->HCNTR_d == 0) && ((ec->Lu_d/ec->Ly_d) < DEFAULT_SUPPR) &&
+      (ec->Lu_d/ec->Ly_d > EC_MIN_DB_VALUE)) { 
+    suppr_factor = (10/(float)(SUPPR_FLOOR-SUPPR_CEIL))*log(ec->Lu_d/ec->Ly_d)
+      - SUPPR_CEIL/(float)(SUPPR_FLOOR - SUPPR_CEIL);
+
+    u_suppr = pow(10.0,(suppr_factor)*RES_SUPR_FACTOR/10.0)*u_suppr;
+    
+  }
+#endif  
+  ec->i_d++;
+  return u;
+}
+
+static inline echo_can_state_t *echo_can_create(int len, int adaption_mode)
+{
+	echo_can_state_t *ec;
+	int maxy;
+	int maxu;
+	maxy = len + DEFAULT_M;
+	maxu = DEFAULT_M;
+	if (maxy < (1 << DEFAULT_ALPHA_YT_I))
+		maxy = (1 << DEFAULT_ALPHA_YT_I);
+	if (maxy < (1 << DEFAULT_SIGMA_LY_I))
+		maxy = (1 << DEFAULT_SIGMA_LY_I);
+	if (maxu < (1 << DEFAULT_SIGMA_LU_I))
+		maxu = (1 << DEFAULT_SIGMA_LU_I);
+	ec = (echo_can_state_t *)MALLOC(sizeof(echo_can_state_t) +
+									4 + 						/* align */
+									sizeof(int) * len +			/* a_i */
+									sizeof(short) * len + 		/* a_s */
+									2 * sizeof(short) * (maxy) +	/* y_s */
+									2 * sizeof(short) * (1 << DEFAULT_ALPHA_ST_I) + /* s_s */
+									2 * sizeof(short) * (maxu) +		/* u_s */
+									2 * sizeof(short) * len);			/* y_tilde_s */
+	if (ec) {
+		memset(ec, 0, sizeof(echo_can_state_t) +
+									4 + 						/* align */
+									sizeof(int) * len +			/* a_i */
+									sizeof(short) * len + 		/* a_s */
+									2 * sizeof(short) * (maxy) +	/* y_s */
+									2 * sizeof(short) * (1 << DEFAULT_ALPHA_ST_I) + /* s_s */
+									2 * sizeof(short) * (maxu) +		/* u_s */
+									2 * sizeof(short) * len);			/* y_tilde_s */
+	  init_cc(ec, len, maxy, maxu);
+	}
+	return ec;
+}
+
+
+
+#endif