mirror of
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152 lines
3.6 KiB
C
152 lines
3.6 KiB
C
/* GStreamer
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* Copyright (C) 2009 Tiago Katcipis <tiagokatcipis@gmail.com>
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* Copyright (C) 2009 Paulo Pizarro <paulo.pizarro@gmail.com>
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* Copyright (C) 2009 Rogério Santos <rogerio.santos@digitro.com.br>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <glib.h>
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#include "vad_private.h"
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#define VAD_POWER_ALPHA 0x0800 /* Q16 */
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#define VAD_POWER_THRESHOLD 0x000010C7 /* -60 dB (square wave) */
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#define VAD_ZCR_THRESHOLD 0
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#define VAD_BUFFER_SIZE 256
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union pgen
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{
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guint64 a;
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gpointer v;
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guint64 *l;
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guchar *b;
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guint16 *w;
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gint16 *s;
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};
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struct _cqueue_s
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{
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union pgen base;
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union pgen tail;
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union pgen head;
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gint size;
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};
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typedef struct _cqueue_s cqueue_t;
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struct _vad_s
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{
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gint16 vad_buffer[VAD_BUFFER_SIZE];
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cqueue_t cqueue;
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gint vad_state;
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guint64 hysteresis;
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guint64 vad_samples;
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guint64 vad_power;
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long vad_zcr;
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};
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VADFilter *
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vad_new (guint64 hysteresis)
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{
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VADFilter *vad = malloc (sizeof (VADFilter));
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vad_reset (vad);
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vad->hysteresis = hysteresis;
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return vad;
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}
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void
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vad_reset (VADFilter * vad)
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{
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memset (vad, 0, sizeof (vad));
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vad->cqueue.base.s = vad->vad_buffer;
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vad->cqueue.tail.a = vad->cqueue.head.a = 0;
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vad->cqueue.size = VAD_BUFFER_SIZE;
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vad->vad_state = VAD_SILENCE;
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}
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void
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vad_destroy (VADFilter * p)
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{
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free (p);
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}
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void
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vad_set_hysteresis (struct _vad_s *p, guint64 hysteresis)
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{
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p->hysteresis = hysteresis;
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}
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guint64
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vad_get_hysteresis (struct _vad_s *p)
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{
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return p->hysteresis;
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}
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gint
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vad_update (struct _vad_s * p, gint16 * data, gint len)
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{
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guint64 tail;
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gint frame_type;
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gint16 sample;
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gint i;
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for (i = 0; i < len; i++) {
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p->vad_power = VAD_POWER_ALPHA * ((data[i] * data[i] >> 14) & 0xFFFF) +
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(0xFFFF - VAD_POWER_ALPHA) * (p->vad_power >> 16) +
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((0xFFFF - VAD_POWER_ALPHA) * (p->vad_power & 0xFFFF) >> 16);
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/* Update VAD buffer */
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p->cqueue.base.s[p->cqueue.head.a] = data[i];
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p->cqueue.head.a = (p->cqueue.head.a + 1) & (p->cqueue.size - 1);
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if (p->cqueue.head.a == p->cqueue.tail.a)
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p->cqueue.tail.a = (p->cqueue.tail.a + 1) & (p->cqueue.size - 1);
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}
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tail = p->cqueue.tail.a;
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p->vad_zcr = 0;
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for (;;) {
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sample = p->cqueue.base.s[tail];
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tail = (tail + 1) & (p->cqueue.size - 1);
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if (tail == p->cqueue.head.a)
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break;
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p->vad_zcr +=
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((sample & 0x8000) != (p->cqueue.base.s[tail] & 0x8000)) ? 1 : -1;
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}
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frame_type = (p->vad_power > VAD_POWER_THRESHOLD
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&& p->vad_zcr < VAD_ZCR_THRESHOLD) ? VAD_VOICE : VAD_SILENCE;
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if (p->vad_state != frame_type) {
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/* Voice to silence transition */
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if (p->vad_state == VAD_VOICE) {
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p->vad_samples += len;
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if (p->vad_samples >= p->hysteresis) {
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p->vad_state = frame_type;
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p->vad_samples = 0;
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}
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} else {
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p->vad_state = frame_type;
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p->vad_samples = 0;
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}
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} else {
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p->vad_samples = 0;
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}
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return p->vad_state;
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}
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