--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/src/time_scale.c	Fri Jun 25 15:50:58 2010 +0200
@@ -0,0 +1,287 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * time_scale.c - Time scaling for linear speech data
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2004 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1,
+ * as published by the Free Software Foundation.
+ *
+ * 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: time_scale.c,v 1.30 2009/02/10 13:06:47 steveu Exp $
+ */
+
+/*! \file */
+
+#if defined(HAVE_CONFIG_H)
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <inttypes.h>
+#include <string.h>
+#include <fcntl.h>
+#include <time.h>
+#include <limits.h>
+#if defined(HAVE_TGMATH_H)
+#include <tgmath.h>
+#endif
+#if defined(HAVE_MATH_H)
+#include <math.h>
+#endif
+#include "floating_fudge.h"
+
+#include "spandsp/telephony.h"
+#include "spandsp/fast_convert.h"
+#include "spandsp/time_scale.h"
+#include "spandsp/saturated.h"
+
+#include "spandsp/private/time_scale.h"
+
+/*
+    Time scaling for speech, based on the Pointer Interval Controlled
+    OverLap and Add (PICOLA) method, developed by Morita Naotaka.
+ */
+
+static __inline__ int amdf_pitch(int min_pitch, int max_pitch, int16_t amp[], int len)
+{
+    int i;
+    int j;
+    int acc;
+    int min_acc;
+    int pitch;
+
+    pitch = min_pitch;
+    min_acc = INT_MAX;
+    for (i = max_pitch;  i <= min_pitch;  i++)
+    {
+        acc = 0;
+        for (j = 0;  j < len;  j++)
+            acc += abs(amp[i + j] - amp[j]);
+        if (acc < min_acc)
+        {
+            min_acc = acc;
+            pitch = i;
+        }
+    }
+    return pitch;
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ void overlap_add(int16_t amp1[], int16_t amp2[], int len)
+{
+    int i;
+    float weight;
+    float step;
+    
+    step = 1.0f/len;
+    weight = 0.0f;
+    for (i = 0;  i < len;  i++)
+    {
+        /* TODO: saturate */
+        amp2[i] = (int16_t) ((float) amp1[i]*(1.0f - weight) + (float) amp2[i]*weight);
+        weight += step;
+    }
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int) time_scale_rate(time_scale_state_t *s, float playout_rate)
+{
+    if (playout_rate <= 0.0f)
+        return -1;
+    /*endif*/
+    if (playout_rate >= 0.99f  &&  playout_rate <= 1.01f)
+    {
+        /* Treat rate close to normal speed as exactly normal speed, and
+           avoid divide by zero, and other numerical problems. */
+        playout_rate = 1.0f;
+    }
+    else if (playout_rate < 1.0f)
+    {
+        s->rcomp = playout_rate/(1.0f - playout_rate);
+    }
+    else
+    {
+        s->rcomp = 1.0f/(playout_rate - 1.0f);
+    }
+    /*endif*/
+    s->playout_rate = playout_rate;
+    return 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(time_scale_state_t *) time_scale_init(time_scale_state_t *s, int sample_rate, float playout_rate)
+{
+    int alloced;
+
+    if (sample_rate > TIME_SCALE_MAX_SAMPLE_RATE)
+        return NULL;
+    alloced = FALSE;
+    if (s == NULL)
+    {
+        if ((s = (time_scale_state_t *) malloc(sizeof (*s))) == NULL)
+            return  NULL;
+        /*endif*/
+        alloced = TRUE;
+    }
+    /*endif*/
+    s->sample_rate = sample_rate;
+    s->min_pitch = sample_rate/TIME_SCALE_MIN_PITCH;
+    s->max_pitch = sample_rate/TIME_SCALE_MAX_PITCH;
+    s->buf_len = 2*sample_rate/TIME_SCALE_MIN_PITCH;
+    if (time_scale_rate(s, playout_rate))
+    {
+        if (alloced)
+            free(s);
+        return NULL;
+    }
+    /*endif*/
+    s->rate_nudge = 0.0f;
+    s->fill = 0;
+    s->lcp = 0;
+    return s;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int) time_scale_release(time_scale_state_t *s)
+{
+    return 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int) time_scale_free(time_scale_state_t *s)
+{
+    free(s);
+    return 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int) time_scale(time_scale_state_t *s, int16_t out[], int16_t in[], int len)
+{
+    double lcpf;
+    int pitch;
+    int out_len;
+    int in_len;
+    int k;
+
+    out_len = 0;
+    in_len = 0;
+
+    /* Top up the buffer */
+    if (s->fill + len < s->buf_len)
+    {
+        /* Cannot continue without more samples */
+        memcpy(s->buf + s->fill, in, sizeof(int16_t)*len);
+        s->fill += len;
+        return out_len;
+    }
+    k = s->buf_len - s->fill;
+    memcpy(s->buf + s->fill, in, sizeof(int16_t)*k);
+    in_len += k;
+    s->fill = s->buf_len;
+    while (s->fill == s->buf_len)
+    {
+        while (s->lcp >= s->buf_len)
+        {
+            memcpy(out + out_len, s->buf, sizeof(int16_t)*s->buf_len);
+            out_len += s->buf_len;
+            if (len - in_len < s->buf_len)
+            {
+                /* Cannot continue without more samples */
+                memcpy(s->buf, in + in_len, sizeof(int16_t)*(len - in_len));
+                s->fill = len - in_len;
+                s->lcp -= s->buf_len;
+                return out_len;
+            }
+            memcpy(s->buf, in + in_len, sizeof(int16_t)*s->buf_len);
+            in_len += s->buf_len;
+            s->lcp -= s->buf_len;
+        }
+        if (s->lcp > 0)
+        {
+            memcpy(out + out_len, s->buf, sizeof(int16_t)*s->lcp);
+            out_len += s->lcp;
+            memcpy(s->buf, s->buf + s->lcp, sizeof(int16_t)*(s->buf_len - s->lcp));
+            if (len - in_len < s->lcp)
+            {
+                /* Cannot continue without more samples */
+                memcpy(s->buf + (s->buf_len - s->lcp), in + in_len, sizeof(int16_t)*(len - in_len));
+                s->fill = s->buf_len - s->lcp + len - in_len;
+                s->lcp = 0;
+                return out_len;
+            }
+            memcpy(s->buf + (s->buf_len - s->lcp), in + in_len, sizeof(int16_t)*s->lcp);
+            in_len += s->lcp;
+            s->lcp = 0;
+        }
+        if (s->playout_rate == 1.0f)
+        {
+            s->lcp = 0x7FFFFFFF;
+        }
+        else
+        {
+            pitch = amdf_pitch(s->min_pitch, s->max_pitch, s->buf, s->min_pitch);
+            lcpf = (double) pitch*s->rcomp;
+            /* Nudge around to compensate for fractional samples */
+            s->lcp = (int) lcpf;
+            /* Note that s->lcp and lcpf are not the same, as lcpf has a fractional part, and s->lcp doesn't */
+            s->rate_nudge += s->lcp - lcpf;
+            if (s->rate_nudge >= 0.5f)
+            {
+                s->lcp--;
+                s->rate_nudge -= 1.0f;
+            }
+            else if (s->rate_nudge <= -0.5f)
+            {
+                s->lcp++;
+                s->rate_nudge += 1.0f;
+            }
+            if (s->playout_rate < 1.0f)
+            {
+                /* Speed up - drop a chunk of data */
+                overlap_add(s->buf, s->buf + pitch, pitch);
+                memcpy(&s->buf[pitch], &s->buf[2*pitch], sizeof(int16_t)*(s->buf_len - 2*pitch));
+                if (len - in_len < pitch)
+                {
+                    /* Cannot continue without more samples */
+                    memcpy(s->buf + s->buf_len - pitch, in + in_len, sizeof(int16_t)*(len - in_len));
+                    s->fill += (len - in_len - pitch);
+                    return out_len;
+                }
+                memcpy(s->buf + s->buf_len - pitch, in + in_len, sizeof(int16_t)*pitch);
+                in_len += pitch;
+            }
+            else
+            {
+                /* Slow down - insert a chunk of data */
+                memcpy(out + out_len, s->buf, sizeof(int16_t)*pitch);
+                out_len += pitch;
+                overlap_add(s->buf + pitch, s->buf, pitch);
+            }
+        }
+    }
+    return out_len;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int) time_scale_max_output_len(time_scale_state_t *s, int input_len)
+{
+    return (int) (input_len*s->playout_rate + s->min_pitch + 1);
+}
+/*- End of function --------------------------------------------------------*/
+/*- End of file ------------------------------------------------------------*/