AmAudio class that mixes in a file into an audio at regular intervals

git-svn-id: http://svn.berlios.de/svnroot/repos/sems/trunk@394 8eb893ce-cfd4-0310-b710-fb5ebe64c474

core/AmAudioMixIn.cpp

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+/*
+ * $Id: AmAudioMixIn.cpp 322 2007-05-02 18:49:26Z sayer $
+ *
+ * Copyright (C) 2007 iptego GmbH
+ *
+ * This file is part of sems, a free SIP media server.
+ *
+ * sems 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.
+ *
+ * For a license to use the sems software under conditions
+ * other than those described here, or to purchase support for this
+ * software, please contact iptel.org by e-mail at the following addresses:
+ *    info@iptel.org
+ *
+ * sems 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 "AmAudioMixIn.h"
+#include "SampleArray.h"
+
+AmAudioMixIn::AmAudioMixIn(AmAudio* A, AmAudioFile* B, 
+			     unsigned int s, double l) 
+  :   A(A),B(B), s(s), l(l), mixing(false), next_start_ts_i(false)
+{
+}
+AmAudioMixIn::~AmAudioMixIn() { }
+
+int AmAudioMixIn::get(unsigned int user_ts, unsigned char* buffer, 
+		       unsigned int nb_samples) {
+  if (!mixing) {
+    if (!next_start_ts_i) {
+      next_start_ts_i = true;
+      next_start_ts = user_ts + s*DEFAULT_SAMPLE_RATE;
+    } else {
+      if (ts_less()(next_start_ts, user_ts)) {
+	DBG("starting mix-in\n");
+	mixing = true;
+	next_start_ts = user_ts + s*DEFAULT_SAMPLE_RATE;
+      }
+    }
+  } 
+  
+  if (!mixing) {
+    return A->get(user_ts, buffer, nb_samples);
+  } else {
+    if (l < 0.01) { // epsilon 
+      // only play back from B
+      int res = B->get(user_ts, buffer, nb_samples);
+      if (res <= 0) { // B empty
+	res = A->get(user_ts, buffer, nb_samples);
+	mixing = false;
+	B->rewind();
+      }
+      return  res;
+    } else {      // mix the two
+      int res = 0;
+      short* pdest = (short*)buffer;
+      // get audio from A
+      int len = A->get(user_ts, (unsigned char*)mix_buf, nb_samples);
+
+      if (len<0) { // A finished
+	return len;
+      }
+      for (int i=0;i<len;i++) {
+	pdest[i]=(short)(((double)mix_buf[i])*(1.0-l));
+      }
+
+      res = len;
+
+      // clear the rest
+      if (nb_samples<<1 != (unsigned int)len)
+	memset((void*)pdest[len], 0, nb_samples<<1 - (unsigned int)len);
+
+      // add audio from B
+      len = B->get(user_ts, (unsigned char*)mix_buf, nb_samples);
+
+      if (len<0) { // B finished
+	mixing = false;
+	B->rewind();
+      } else {
+	for (int i=0;i<len;i++) {
+	  pdest[i]+=(short)(((double)mix_buf[i])*l);
+	}
+	if (len>res) // audio from B is longer than from A
+	  res = len;
+      }
+      return res;
+    }
+  }
+}
+
+int AmAudioMixIn::put(unsigned int user_ts, unsigned char* buffer, unsigned int size) {
+  ERROR("writing not supported\n");
+  return -1;
+}

core/AmAudioMixIn.h

@@ -0,0 +1,76 @@
+/*
+ * $Id: AmAudioMixIn.h 322 2007-05-02 18:49:26Z sayer $
+ *
+ * Copyright (C) 2007 iptego GmbH
+ *
+ * This file is part of sems, a free SIP media server.
+ *
+ * sems 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.
+ *
+ * For a license to use the sems software under conditions
+ * other than those described here, or to purchase support for this
+ * software, please contact iptel.org by e-mail at the following addresses:
+ *    info@iptel.org
+ *
+ * sems 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
+ */
+
+#ifndef _AM_AUDIO_MIX_IN_H
+#define _AM_AUDIO_MIX_IN_H
+
+#include "AmAudio.h"
+
+
+#define MAX_PACKETLENGTH_MS   30
+#define MAX_BUF_SAMPLES  8000 * MAX_PACKETLENGTH_MS / 1000
+#define DEFAULT_SAMPLE_RATE 8000 // eh...
+
+/**
+ * \brief \ref AmAudio to mix in every n seconds a file
+ * 
+ * AmAudio that plays Audio A and 
+ * every s seconds mixes in AudioFile B with level l.
+ * If l == 0, playback of A is not continued when playing B,
+ * which means that it continues right where it was before 
+ * playback of B started.
+ *
+ */
+class AmAudioMixIn : public AmAudio {
+  AmAudio* A;
+  AmAudioFile* B;
+  unsigned int s;
+  double l;
+
+  bool mixing;
+
+  unsigned int next_start_ts;
+  bool next_start_ts_i;
+
+  short mix_buf[MAX_BUF_SAMPLES];  // 240
+
+ public:
+  AmAudioMixIn(AmAudio* A, AmAudioFile* B, 
+		unsigned int s, double l);
+  ~AmAudioMixIn();
+ protected:
+  // not used
+  int read(unsigned int user_ts, unsigned int size){ return -1; }
+  int write(unsigned int user_ts, unsigned int size){ return -1; }
+    
+  // override AmAudio
+  int get(unsigned int user_ts, unsigned char* buffer, unsigned int nb_samples);
+  int put(unsigned int user_ts, unsigned char* buffer, unsigned int size);
+};
+
+
+#endif // _AM_AUDIO_MIX_IN_H