major redesign of the channel spy infrastructure, increasing efficiency and reducing locking conflicts

(nearly) complete rewrite of app_muxmon, renaming the application to MixMonitor and fixing a large number of bugs and inconsistencies
update app_chanspy to use new spy infrastructure


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@6884 f38db490-d61c-443f-a65b-d21fe96a405b

6 files changed, 1085 insertions, 1002 deletions

diff --git a/.cleancount b/.cleancount
index 7f8f011eb..45a4fb75d 100755
--- a/.cleancount
+++ b/.cleancount
@@ -1 +1 @@
-7
+8
diff --git a/apps/app_chanspy.c b/apps/app_chanspy.c
index 036c5edef..d9138ed00 100755
--- a/apps/app_chanspy.c
+++ b/apps/app_chanspy.c
@@ -35,7 +35,6 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/channel.h"
 #include "asterisk/features.h"
 #include "asterisk/options.h"
-#include "asterisk/slinfactory.h"
 #include "asterisk/app.h"
 #include "asterisk/utils.h"
 #include "asterisk/say.h"
@@ -68,6 +67,8 @@ static const char *desc = "   Chanspy([<scanspec>][|<options>])\n\n"
 "(e.g. run Chanspy(Agent) and dial 1234# while spying to jump to channel Agent/1234)\n\n"
 "";
 
+static const char *chanspy_spy_type = "ChanSpy";
+
 #define OPTION_QUIET	 (1 << 0)	/* Quiet, no announcement */
 #define OPTION_BRIDGED   (1 << 1)	/* Only look at bridged calls */
 #define OPTION_VOLUME    (1 << 2)	/* Specify initial volume */
@@ -88,39 +89,10 @@ LOCAL_USER_DECL;
 struct chanspy_translation_helper {
 	/* spy data */
 	struct ast_channel_spy spy;
-	int volfactor;
 	int fd;
-	struct ast_slinfactory slinfactory[2];
+	int volfactor;
 };
 
-/* Prototypes */
-static struct ast_channel *local_get_channel_begin_name(char *name);
-static struct ast_channel *local_channel_walk(struct ast_channel *chan);
-static void spy_release(struct ast_channel *chan, void *data);
-static void *spy_alloc(struct ast_channel *chan, void *params);
-static struct ast_frame *spy_queue_shift(struct ast_channel_spy *spy, int qnum);
-static void ast_flush_spy_queue(struct ast_channel_spy *spy);
-static int spy_generate(struct ast_channel *chan, void *data, int len, int samples);
-static void start_spying(struct ast_channel *chan, struct ast_channel *spychan, struct ast_channel_spy *spy);
-static void stop_spying(struct ast_channel *chan, struct ast_channel_spy *spy);
-static int channel_spy(struct ast_channel *chan, struct ast_channel *spyee, int *volfactor, int fd);
-static int chanspy_exec(struct ast_channel *chan, void *data);
-
-
-#if 0
-static struct ast_channel *local_get_channel_by_name(char *name) 
-{
-	struct ast_channel *ret;
-	ast_mutex_lock(&modlock);
-	if ((ret = ast_get_channel_by_name_locked(name))) {
-		ast_mutex_unlock(&ret->lock);
-	}
-	ast_mutex_unlock(&modlock);
-
-	return ret;
-}
-#endif
-
 static struct ast_channel *local_channel_walk(struct ast_channel *chan) 
 {
 	struct ast_channel *ret;
@@ -149,247 +121,85 @@ static struct ast_channel *local_get_channel_begin_name(char *name)
 	return ret;
 }
 
-
-static void spy_release(struct ast_channel *chan, void *data) 
-{
-	struct chanspy_translation_helper *csth = data;
-
-	ast_slinfactory_destroy(&csth->slinfactory[0]);
-	ast_slinfactory_destroy(&csth->slinfactory[1]);
-
-	return;
-}
-
-static void *spy_alloc(struct ast_channel *chan, void *params) 
-{
-	struct chanspy_translation_helper *csth = params;
-	ast_slinfactory_init(&csth->slinfactory[0]);
-	ast_slinfactory_init(&csth->slinfactory[1]);
-	return params;
-}
-
-static struct ast_frame *spy_queue_shift(struct ast_channel_spy *spy, int qnum) 
-{
-	struct ast_frame *f;
-	
-	if (qnum < 0 || qnum > 1)
-		return NULL;
-
-	f = spy->queue[qnum];
-	if (f) {
-		spy->queue[qnum] = f->next;
-		return f;
-	}
-	return NULL;
-}
-
-
-static void ast_flush_spy_queue(struct ast_channel_spy *spy) 
+static void *spy_alloc(struct ast_channel *chan, void *data)
 {
-	struct ast_frame *f=NULL;
-	int x = 0;
-	ast_mutex_lock(&spy->lock);
-	for(x=0;x<2;x++) {
-		f = NULL;
-		while((f = spy_queue_shift(spy, x))) 
-			ast_frfree(f);
-	}
-	ast_mutex_unlock(&spy->lock);
+	/* just store the data pointer in the channel structure */
+	return data;
 }
 
-
-#if 0
-static int extract_audio(short *buf, size_t len, struct ast_trans_pvt *trans, struct ast_frame *fr, int *maxsamp)
+static void spy_release(struct ast_channel *chan, void *data)
 {
-	struct ast_frame *f;
-	int size, retlen = 0;
-	
-	if (trans) {
-		if ((f = ast_translate(trans, fr, 0))) {
-			size = (f->datalen > len) ? len : f->datalen;
-			memcpy(buf, f->data, size);
-			retlen = f->datalen;
-			ast_frfree(f);
-		} else {
-			/* your guess is as good as mine why this will happen but it seems to only happen on iax and appears harmless */
-			ast_log(LOG_DEBUG, "Failed to translate frame from %s\n", ast_getformatname(fr->subclass));
-		}
-	} else {
-		size = (fr->datalen > len) ? len : fr->datalen;
-		memcpy(buf, fr->data, size);
-		retlen = fr->datalen;
-	}
-
-	if (retlen > 0 && (size = retlen / 2)) {
-		if (size > *maxsamp) {
-			*maxsamp = size;
-		}
-	}
-	
-	return retlen;
-}
-
-
-static int spy_queue_ready(struct ast_channel_spy *spy)
-{
-	int res = 0;
-
-	ast_mutex_lock(&spy->lock);
-	if (spy->status == CHANSPY_RUNNING) {
-		res = (spy->queue[0] && spy->queue[1]) ? 1 : 0;
-	} else {
-		res = (spy->queue[0] || spy->queue[1]) ? 1 : -1;
-	}
-	ast_mutex_unlock(&spy->lock);
-	return res;
+	/* nothing to do */
 }
-#endif
 
 static int spy_generate(struct ast_channel *chan, void *data, int len, int samples) 
 {
-
 	struct chanspy_translation_helper *csth = data;
-	struct ast_frame frame, *f;
-	int len0 = 0, len1 = 0, samp0 = 0, samp1 = 0, x, vf, maxsamp;
-	short buf0[1280], buf1[1280], buf[1280];
+	struct ast_frame *f;
 		
-	if (csth->spy.status == CHANSPY_DONE) {
+	if (csth->spy.status != CHANSPY_RUNNING)
 		/* Channel is already gone more than likely */
 		return -1;
-	}
 
 	ast_mutex_lock(&csth->spy.lock);
-	while((f = csth->spy.queue[0])) {
-		csth->spy.queue[0] = f->next;
-		ast_slinfactory_feed(&csth->slinfactory[0], f);
-		ast_frfree(f);
-	}
-	ast_mutex_unlock(&csth->spy.lock);
-	ast_mutex_lock(&csth->spy.lock);
-	while((f = csth->spy.queue[1])) {
-		csth->spy.queue[1] = f->next;
-		ast_slinfactory_feed(&csth->slinfactory[1], f);
-		ast_frfree(f);
-	}
+	f = ast_channel_spy_read_frame(&csth->spy, samples);
 	ast_mutex_unlock(&csth->spy.lock);
 		
-	if (csth->slinfactory[0].size < len || csth->slinfactory[1].size < len) {
+	if (!f)
 		return 0;
-	}
-		
-	if ((len0 = ast_slinfactory_read(&csth->slinfactory[0], buf0, len))) {
-		samp0 = len0 / 2;
-	} 
-	if ((len1 = ast_slinfactory_read(&csth->slinfactory[1], buf1, len))) {
-		samp1 = len1 / 2;
-	}
-
-	maxsamp = (samp0 > samp1) ? samp0 : samp1;
-	vf = get_volfactor(csth->volfactor);
 		
-	for(x=0; x < maxsamp; x++) {
-		if (vf < 0) {
-			if (samp0) {
-				buf0[x] /= abs(vf);
-			}
-			if (samp1) {
-				buf1[x] /= abs(vf);
-			}
-		} else if (vf > 0) {
-			if (samp0) {
-				buf0[x] *= vf;
-			}
-			if (samp1) {
-				buf1[x] *= vf;
-			}
-		}
-		if (samp0 && samp1) {
-			if (x < samp0 && x < samp1) {
-				buf[x] = buf0[x] + buf1[x];
-			} else if (x < samp0) {
-				buf[x] = buf0[x];
-			} else if (x < samp1) {
-				buf[x] = buf1[x];
-			}
-		} else if (x < samp0) {
-			buf[x] = buf0[x];
-		} else if (x < samp1) {
-			buf[x] = buf1[x];
-		}
-	}
-		
-	memset(&frame, 0, sizeof(frame));
-	frame.frametype = AST_FRAME_VOICE;
-	frame.subclass = AST_FORMAT_SLINEAR;
-	frame.data = buf;
-	frame.samples = x;
-	frame.datalen = x * 2;
-
-	if (ast_write(chan, &frame)) {
+	if (ast_write(chan, f)) {
+		ast_frfree(f);
 		return -1;
 	}
 
-	if (csth->fd) {
-		write(csth->fd, buf1, len1);
-	}
+	if (csth->fd)
+		write(csth->fd, f->data, f->datalen);
+
+	ast_frfree(f);
 
 	return 0;
 }
 
 
 static struct ast_generator spygen = {
-	alloc: spy_alloc, 
-	release: spy_release, 
-	generate: spy_generate, 
+	.alloc = spy_alloc,
+	.release = spy_release,
+	.generate = spy_generate, 
 };
 
-static void start_spying(struct ast_channel *chan, struct ast_channel *spychan, struct ast_channel_spy *spy) 
+static int start_spying(struct ast_channel *chan, struct ast_channel *spychan, struct ast_channel_spy *spy) 
 {
-
-	struct ast_channel_spy *cptr=NULL;
+	int res;
 	struct ast_channel *peer;
 
-
-	ast_log(LOG_WARNING, "Attaching %s to %s\n", spychan->name, chan->name);
-
+	ast_log(LOG_NOTICE, "Attaching %s to %s\n", spychan->name, chan->name);
 
 	ast_mutex_lock(&chan->lock);
-	if (chan->spiers) {
-		for(cptr=chan->spiers;cptr && cptr->next;cptr=cptr->next);
-		cptr->next = spy;
-	} else {
-		chan->spiers = spy;
-	}
+	res = ast_channel_spy_add(chan, spy);
 	ast_mutex_unlock(&chan->lock);
-	if ( ast_test_flag(chan, AST_FLAG_NBRIDGE) && (peer = ast_bridged_channel(chan))) {
+
+	if (!res && ast_test_flag(chan, AST_FLAG_NBRIDGE) && (peer = ast_bridged_channel(chan))) {
 		ast_softhangup(peer, AST_SOFTHANGUP_UNBRIDGE);	
 	}
 
+	return res;
 }
 
 static void stop_spying(struct ast_channel *chan, struct ast_channel_spy *spy) 
 {
-	struct ast_channel_spy *cptr=NULL, *prev=NULL;
-
 	/* If our status has changed, then the channel we're spying on is gone....
 	   DON'T TOUCH IT!!!  RUN AWAY!!! */
 	if (spy->status != CHANSPY_RUNNING)
 		return;
 
+	if (!chan)
+		return;
+
 	ast_mutex_lock(&chan->lock);
-	for(cptr=chan->spiers; cptr; cptr=cptr->next) {
-		if (cptr == spy) {
-			if (prev) {
-				prev->next = cptr->next;
-				cptr->next = NULL;
-			} else
-				chan->spiers = NULL;
-		}
-		prev = cptr;
-	}
+	ast_channel_spy_remove(chan, spy);
 	ast_mutex_unlock(&chan->lock);
-
-}
+};
 
 /* Map 'volume' levels from -4 through +4 into
    decibel (dB) settings for channel drivers
@@ -414,35 +224,47 @@ static void set_volume(struct ast_channel *chan, struct chanspy_translation_help
 {
 	signed char volume_adjust = volfactor_map[csth->volfactor + 4];
 
-	if (!ast_channel_setoption(chan, AST_OPTION_TXGAIN, &volume_adjust, sizeof(volume_adjust), 0)) {
+	if (!ast_channel_setoption(chan, AST_OPTION_TXGAIN, &volume_adjust, sizeof(volume_adjust), 0))
 		csth->volfactor = 0;
-	}
 }
 
 static int channel_spy(struct ast_channel *chan, struct ast_channel *spyee, int *volfactor, int fd) 
 {
 	struct chanspy_translation_helper csth;
-	int running = 1, res = 0, x = 0;
+	int running, res = 0, x = 0;
 	char inp[24];
 	char *name=NULL;
 	struct ast_frame *f;
 
-	if (chan && !ast_check_hangup(chan) && spyee && !ast_check_hangup(spyee)) {
+	running = (chan && !ast_check_hangup(chan) && spyee && !ast_check_hangup(spyee));
+
+	if (running) {
 		memset(inp, 0, sizeof(inp));
 		name = ast_strdupa(spyee->name);
 		if (option_verbose >= 2)
 			ast_verbose(VERBOSE_PREFIX_2 "Spying on channel %s\n", name);
 
 		memset(&csth, 0, sizeof(csth));
+		ast_set_flag(&csth.spy, CHANSPY_FORMAT_AUDIO);
+		ast_set_flag(&csth.spy, CHANSPY_TRIGGER_NONE);
+		ast_set_flag(&csth.spy, CHANSPY_MIXAUDIO);
+		csth.spy.type = chanspy_spy_type;
 		csth.spy.status = CHANSPY_RUNNING;
+		csth.spy.read_queue.format = AST_FORMAT_SLINEAR;
+		csth.spy.write_queue.format = AST_FORMAT_SLINEAR;
 		ast_mutex_init(&csth.spy.lock);
 		csth.volfactor = *volfactor;
 		set_volume(chan, &csth);
-		
-		if (fd) {
-			csth.fd = fd;
-		}
-		start_spying(spyee, chan, &csth.spy);
+		csth.spy.read_vol_adjustment = csth.volfactor;
+		csth.spy.write_vol_adjustment = csth.volfactor;
+		csth.fd = fd;
+
+		if (start_spying(spyee, chan, &csth.spy))
+			running = 0;
+	}
+
+	if (running) {
+		running = 1;
 		ast_activate_generator(chan, &spygen, &csth);
 
 		while (csth.spy.status == CHANSPY_RUNNING &&
@@ -487,6 +309,8 @@ static int channel_spy(struct ast_channel *chan, struct ast_channel *spyee, int
 					}
 					csth.volfactor = *volfactor;
 					set_volume(chan, &csth);
+					csth.spy.read_vol_adjustment = csth.volfactor;
+					csth.spy.write_vol_adjustment = csth.volfactor;
 				}
 			} else if (res >= 48 && res <= 57) {
 				inp[x++] = res;
@@ -498,11 +322,12 @@ static int channel_spy(struct ast_channel *chan, struct ast_channel *spyee, int
 		if (option_verbose >= 2) {
 			ast_verbose(VERBOSE_PREFIX_2 "Done Spying on channel %s\n", name);
 		}
-		ast_flush_spy_queue(&csth.spy);
 	} else {
 		running = 0;
 	}
+
 	ast_mutex_destroy(&csth.spy.lock);
+
 	return running;
 }
 
diff --git a/apps/app_mixmonitor.c b/apps/app_mixmonitor.c
index ab8045835..c166c71aa 100755
--- a/apps/app_mixmonitor.c
+++ b/apps/app_mixmonitor.c
@@ -1,46 +1,64 @@
 /*
- * Asterisk -- A telephony toolkit for Linux.
- *
+ * Asterisk -- An open source telephony toolkit.
  *
  * Copyright (C) 2005, Anthony Minessale II
+ * Copyright (C) 2005, Digium, Inc.
+ *
+ * Mark Spencer <markster@digium.com>
+ * Kevin P. Fleming <kpfleming@digium.com>
  *
+ * Based on app_muxmon.c provided by
  * Anthony Minessale II <anthmct@yahoo.com>
  *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
  * This program is free software, distributed under the terms of
- * the GNU General Public License
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
  */
 
 /*! \file
  * \brief muxmon() - record a call natively
  */
 
-#include <asterisk/file.h>
-#include <asterisk/logger.h>
-#include <asterisk/channel.h>
-#include <asterisk/pbx.h>
-#include <asterisk/module.h>
-#include <asterisk/lock.h>
-#include <asterisk/cli.h>
-#include <asterisk/options.h>
-#include <asterisk/app.h>
-#include <asterisk/translate.h>
-#include <asterisk/slinfactory.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/file.h"
+#include "asterisk/logger.h"
+#include "asterisk/channel.h"
+#include "asterisk/pbx.h"
+#include "asterisk/module.h"
+#include "asterisk/lock.h"
+#include "asterisk/cli.h"
+#include "asterisk/options.h"
+#include "asterisk/app.h"
+#include "asterisk/linkedlists.h"
+
 #define get_volfactor(x) x ? ((x > 0) ? (1 << x) : ((1 << abs(x)) * -1)) : 0
-#define minmax(x,y) x ? (x > y) ? y : ((x < (y * -1)) ? (y * -1) : x) : 0 
-
-static char *tdesc = "Native Channel Monitoring Module";
-static char *app = "MuxMon";
-static char *synopsis = "Record A Call Natively";
-static char *desc = ""
-"  MuxMon(<file>.<ext>[|<options>[|<command>]])\n\n"
-"Records The audio on the current channel to the specified file.\n\n"
-"Valid Options:\n"
-" b    - Only save audio to the file while the channel is bridged. Note: does\n"
-"        not include conferences\n"
-" a    - Append to the file instead of overwriting it.\n"
+
+static const char *tdesc = "Mixed Audio Monitoring Application";
+static const char *app = "MixMonitor";
+static const char *synopsis = "Record a call and mix the audio during the recording";
+static const char *desc = ""
+"  MixMonitor(<file>.<ext>[|<options>[|<command>]])\n\n"
+"Records the audio on the current channel to the specified file.\n"
+"If the filename is an absolute path, uses that path, otherwise\n"
+"creates the file in the configured monitoring directory from\n"
+"asterisk.conf.\n\n"
+"Valid options:\n"
+" a      - Append to the file instead of overwriting it.\n"
+" b      - Only save audio to the file while the channel is bridged.\n"
+"          Note: does not include conferences.\n"
 " v(<x>) - Adjust the heard volume by a factor of <x> (range -4 to 4)\n"	
 " V(<x>) - Adjust the spoken volume by a factor of <x> (range -4 to 4)\n"	
 " W(<x>) - Adjust the both heard and spoken volumes by a factor of <x>\n"
@@ -48,14 +66,16 @@ static char *desc = ""
 "<command> will be executed when the recording is over\n"
 "Any strings matching ^{X} will be unescaped to ${X} and \n"
 "all variables will be evaluated at that time.\n"
-"The variable MUXMON_FILENAME will contain the filename used to record.\n"
+"The variable MIXMONITOR_FILENAME will contain the filename used to record.\n"
 "";
 
 STANDARD_LOCAL_USER;
 
 LOCAL_USER_DECL;
 
-struct muxmon {
+static const char *mixmonitor_spy_type = "MixMonitor";
+
+struct mixmonitor {
 	struct ast_channel *chan;
 	char *filename;
 	char *post_process;
@@ -64,445 +84,341 @@ struct muxmon {
 	int writevol;
 };
 
-typedef enum {
-    MUXFLAG_RUNNING = (1 << 0),
+enum {
     MUXFLAG_APPEND = (1 << 1),
     MUXFLAG_BRIDGED = (1 << 2),
     MUXFLAG_VOLUME = (1 << 3),
     MUXFLAG_READVOLUME = (1 << 4),
-    MUXFLAG_WRITEVOLUME = (1 << 5)
-} muxflags;
-
+    MUXFLAG_WRITEVOLUME = (1 << 5),
+} mixmonitor_flags;
 
-AST_DECLARE_OPTIONS(muxmon_opts,{
-    ['a'] = { MUXFLAG_APPEND },
+AST_DECLARE_OPTIONS(mixmonitor_opts,{
+	['a'] = { MUXFLAG_APPEND },
 	['b'] = { MUXFLAG_BRIDGED },
 	['v'] = { MUXFLAG_READVOLUME, 1 },
 	['V'] = { MUXFLAG_WRITEVOLUME, 2 },
 	['W'] = { MUXFLAG_VOLUME, 3 },
 });
 
-
 static void stopmon(struct ast_channel *chan, struct ast_channel_spy *spy) 
 {
-	struct ast_channel_spy *cptr=NULL, *prev=NULL;
-	int count = 0;
-
-	if (chan) {
-		while(ast_mutex_trylock(&chan->lock)) {
-			if (chan->spiers == spy) {
-				chan->spiers = NULL;
-				return;
-			}
-			count++;
-			if (count > 10) {
-				return;
-			}
-			sched_yield();
-		}
-		
-		for(cptr=chan->spiers; cptr; cptr=cptr->next) {
-			if (cptr == spy) {
-				if (prev) {
-					prev->next = cptr->next;
-					cptr->next = NULL;
-				} else
-					chan->spiers = NULL;
-			}
-			prev = cptr;
-		}
+	/* If our status has changed, then the channel we're spying on is gone....
+	   DON'T TOUCH IT!!!  RUN AWAY!!! */
+	if (spy->status != CHANSPY_RUNNING)
+		return;
 
-		ast_mutex_unlock(&chan->lock);
-	}
+	if (!chan)
+		return;
+
+	ast_mutex_lock(&chan->lock);
+	ast_channel_spy_remove(chan, spy);
+	ast_mutex_unlock(&chan->lock);
 }
 
-static void startmon(struct ast_channel *chan, struct ast_channel_spy *spy) 
+static int startmon(struct ast_channel *chan, struct ast_channel_spy *spy) 
 {
-
-	struct ast_channel_spy *cptr=NULL;
 	struct ast_channel *peer;
+	int res;
 
-	if (chan) {
-		ast_mutex_lock(&chan->lock);
-		if (chan->spiers) {
-			for(cptr=chan->spiers;cptr->next;cptr=cptr->next);
-			cptr->next = spy;
-		} else {
-			chan->spiers = spy;
-		}
-		ast_mutex_unlock(&chan->lock);
+	if (!chan)
+		return -1;
+
+	ast_mutex_lock(&chan->lock);
+	res = ast_channel_spy_add(chan, spy);
+	ast_mutex_unlock(&chan->lock);
 		
-		if (ast_test_flag(chan, AST_FLAG_NBRIDGE) && (peer = ast_bridged_channel(chan))) {
-			ast_softhangup(peer, AST_SOFTHANGUP_UNBRIDGE);	
-		}
-	}
-}
+	if (!res && ast_test_flag(chan, AST_FLAG_NBRIDGE) && (peer = ast_bridged_channel(chan)))
+		ast_softhangup(peer, AST_SOFTHANGUP_UNBRIDGE);	
 
-static int spy_queue_translate(struct ast_channel_spy *spy,
-							   struct ast_slinfactory *slinfactory0,
-							   struct ast_slinfactory *slinfactory1)
-{
-	int res = 0;
-	struct ast_frame *f;
-	
-	ast_mutex_lock(&spy->lock);
-	while((f = spy->queue[0])) {
-		spy->queue[0] = f->next;
-		ast_slinfactory_feed(slinfactory0, f);
-		ast_frfree(f);
-	}
-	ast_mutex_unlock(&spy->lock);
-	ast_mutex_lock(&spy->lock);
-	while((f = spy->queue[1])) {
-		spy->queue[1] = f->next;
-		ast_slinfactory_feed(slinfactory1, f);
-		ast_frfree(f);
-	}
-	ast_mutex_unlock(&spy->lock);
 	return res;
 }
 
-static void *muxmon_thread(void *obj) 
-{
+#define SAMPLES_PER_FRAME 160
 
-	int len0 = 0, len1 = 0, samp0 = 0, samp1 = 0, framelen, maxsamp = 0, x = 0;
-	short buf0[1280], buf1[1280], buf[1280];
-	struct ast_frame frame;
-	struct muxmon *muxmon = obj;
+static void *mixmonitor_thread(void *obj) 
+{
+	struct mixmonitor *mixmonitor = obj;
 	struct ast_channel_spy spy;
 	struct ast_filestream *fs = NULL;
 	char *ext, *name;
 	unsigned int oflags;
-	struct ast_slinfactory slinfactory[2];
+	struct ast_frame *f;
 	char post_process[1024] = "";
 	
-	name = ast_strdupa(muxmon->chan->name);
+	STANDARD_INCREMENT_USECOUNT;
 
-	framelen = 320;
-	frame.frametype = AST_FRAME_VOICE;
-	frame.subclass = AST_FORMAT_SLINEAR;
-	frame.data = buf;
-	ast_set_flag(muxmon, MUXFLAG_RUNNING);
-	oflags = O_CREAT|O_WRONLY;
-	ast_slinfactory_init(&slinfactory[0]);
-	ast_slinfactory_init(&slinfactory[1]);
-	
+	name = ast_strdupa(mixmonitor->chan->name);
 
-
-	/* for efficiency, use a flag to bypass volume logic when it's not needed */
-	if (muxmon->readvol || muxmon->writevol) {
-		ast_set_flag(muxmon, MUXFLAG_VOLUME);
-	}
-
-	if ((ext = strchr(muxmon->filename, '.'))) {
+	oflags = O_CREAT|O_WRONLY;
+	oflags |= ast_test_flag(mixmonitor, MUXFLAG_APPEND) ? O_APPEND : O_TRUNC;
+		
+	if ((ext = strchr(mixmonitor->filename, '.'))) {
 		*(ext++) = '\0';
 	} else {
 		ext = "raw";
 	}
 
+	fs = ast_writefile(mixmonitor->filename, ext, NULL, oflags, 0, 0644);
+	if (!fs) {
+		ast_log(LOG_ERROR, "Cannot open %s.%s\n", mixmonitor->filename, ext);
+		goto out;
+	}
+
+	if (ast_test_flag(mixmonitor, MUXFLAG_APPEND))
+		ast_seekstream(fs, 0, SEEK_END);
+	
 	memset(&spy, 0, sizeof(spy));
+	ast_set_flag(&spy, CHANSPY_FORMAT_AUDIO);
+	ast_set_flag(&spy, CHANSPY_MIXAUDIO);
+	spy.type = mixmonitor_spy_type;
 	spy.status = CHANSPY_RUNNING;
+	spy.read_queue.format = AST_FORMAT_SLINEAR;
+	spy.write_queue.format = AST_FORMAT_SLINEAR;
+	if (mixmonitor->readvol) {
+		ast_set_flag(&spy, CHANSPY_READ_VOLADJUST);
+		spy.read_vol_adjustment = mixmonitor->readvol;
+	}
+	if (mixmonitor->writevol) {
+		ast_set_flag(&spy, CHANSPY_WRITE_VOLADJUST);
+		spy.write_vol_adjustment = mixmonitor->writevol;
+	}
 	ast_mutex_init(&spy.lock);
-	startmon(muxmon->chan, &spy);
-	if (ast_test_flag(muxmon, MUXFLAG_RUNNING)) {
-		if (option_verbose > 1) {
-			ast_verbose(VERBOSE_PREFIX_2 "Begin Muxmon Recording %s\n", name);
-		}
 
-		oflags |= ast_test_flag(muxmon, MUXFLAG_APPEND) ? O_APPEND : O_TRUNC;
-		
-		if (!(fs = ast_writefile(muxmon->filename, ext, NULL, oflags, 0, 0644))) {
-			ast_log(LOG_ERROR, "Cannot open %s\n", muxmon->filename);
-			spy.status = CHANSPY_DONE;
-		}  else {
+	if (startmon(mixmonitor->chan, &spy)) {
+		ast_log(LOG_WARNING, "Unable to add '%s' spy to channel '%s'\n",
+			spy.type, mixmonitor->chan->name);
+		goto out2;
+	}
 
-			if (ast_test_flag(muxmon, MUXFLAG_APPEND)) {
-				ast_seekstream(fs, 0, SEEK_END);
-			}
+	if (option_verbose > 1)
+		ast_verbose(VERBOSE_PREFIX_2 "Begin MixMonitor Recording %s\n", name);
+	
+	while (1) {
+		struct ast_frame *next;
+		int write;
+
+		ast_mutex_lock(&spy.lock);
 
-			while (ast_test_flag(muxmon, MUXFLAG_RUNNING)) {
-				samp0 = samp1 = len0 = len1 = 0;
-
-				if (ast_check_hangup(muxmon->chan) || spy.status != CHANSPY_RUNNING) {
-					ast_clear_flag(muxmon, MUXFLAG_RUNNING);
-					break;
-				}
-
-				if (ast_test_flag(muxmon, MUXFLAG_BRIDGED) && !ast_bridged_channel(muxmon->chan)) {
-					usleep(1000);
-					sched_yield();
-					continue;
-				}
-				
-				spy_queue_translate(&spy, &slinfactory[0], &slinfactory[1]);
-				
-				if (slinfactory[0].size < framelen || slinfactory[1].size < framelen) {
-					usleep(1000);
-					sched_yield();
-					continue;
-				}
-
-				if ((len0 = ast_slinfactory_read(&slinfactory[0], buf0, framelen))) {
-					samp0 = len0 / 2;
-				}
-				if((len1 = ast_slinfactory_read(&slinfactory[1], buf1, framelen))) {
-					samp1 = len1 / 2;
-				}
-				
-				if (ast_test_flag(muxmon, MUXFLAG_VOLUME)) {
-					if (samp0 && muxmon->readvol > 0) {
-						for(x=0; x < samp0 / 2; x++) {
-							buf0[x] *= muxmon->readvol;
-						}
-					} else if (samp0 && muxmon->readvol < 0) {
-						for(x=0; x < samp0 / 2; x++) {
-							buf0[x] /= muxmon->readvol;
-						}
-					}
-					if (samp1 && muxmon->writevol > 0) {
-						for(x=0; x < samp1 / 2; x++) {
-							buf1[x] *= muxmon->writevol;
-						}
-					} else if (muxmon->writevol < 0) {
-						for(x=0; x < samp1 / 2; x++) {
-							buf1[x] /= muxmon->writevol;
-						}
-					}
-				}
-				
-				maxsamp = (samp0 > samp1) ? samp0 : samp1;
-
-				if (samp0 && samp1) {
-					for(x=0; x < maxsamp; x++) {
-						if (x < samp0 && x < samp1) {
-							buf[x] = buf0[x] + buf1[x];
-						} else if (x < samp0) {
-							buf[x] = buf0[x];
-						} else if (x < samp1) {
-							buf[x] = buf1[x];
-						}
-					}
-				} else if(samp0) {
-					memcpy(buf, buf0, len0);
-					x = samp0;
-				} else if(samp1) {
-					memcpy(buf, buf1, len1);
-					x = samp1;
-				}
-
-				frame.samples = x;
-				frame.datalen = x * 2;
-				ast_writestream(fs, &frame);
+		ast_channel_spy_trigger_wait(&spy);
 		
-				usleep(1000);
-				sched_yield();
+		if (ast_check_hangup(mixmonitor->chan) || spy.status != CHANSPY_RUNNING) {
+			ast_mutex_unlock(&spy.lock);
+			break;
+		}
+		
+		while (1) {
+			if (!(f = ast_channel_spy_read_frame(&spy, SAMPLES_PER_FRAME)))
+				break;
+
+			write = (!ast_test_flag(mixmonitor, MUXFLAG_BRIDGED) ||
+				 ast_bridged_channel(mixmonitor->chan));
+
+			/* it is possible for ast_channel_spy_read_frame() to return a chain
+			   of frames if a queue flush was necessary, so process them
+			*/
+			for (; f; f = next) {
+				next = f->next;
+				if (write)
+					ast_writestream(fs, f);
+				ast_frfree(f);
 			}
 		}
-	}
 
-	if (muxmon->post_process) {
+		ast_mutex_unlock(&spy.lock);
+	}
+	
+	if (mixmonitor->post_process) {
 		char *p;
-		for(p = muxmon->post_process; *p ; p++) {
+
+		for (p = mixmonitor->post_process; *p ; p++) {
 			if (*p == '^' && *(p+1) == '{') {
 				*p = '$';
 			}
 		}
-		pbx_substitute_variables_helper(muxmon->chan, muxmon->post_process, post_process, sizeof(post_process) - 1);
-		free(muxmon->post_process);
-		muxmon->post_process = NULL;
+		pbx_substitute_variables_helper(mixmonitor->chan, mixmonitor->post_process, post_process, sizeof(post_process) - 1);
 	}
 
-	stopmon(muxmon->chan, &spy);
-	if (option_verbose > 1) {
-		ast_verbose(VERBOSE_PREFIX_2 "Finished Recording %s\n", name);
-	}
-	ast_mutex_destroy(&spy.lock);
-	
-	if(fs) {
-		ast_closestream(fs);
-	}
-	
-	ast_slinfactory_destroy(&slinfactory[0]);
-	ast_slinfactory_destroy(&slinfactory[1]);
+	stopmon(mixmonitor->chan, &spy);
 
-	if (muxmon) {
-		if (muxmon->filename) {
-			free(muxmon->filename);
-		}
-		free(muxmon);
-	}
+	if (option_verbose > 1)
+		ast_verbose(VERBOSE_PREFIX_2 "End MixMonitor Recording %s\n", name);
 
 	if (!ast_strlen_zero(post_process)) {
-		if (option_verbose > 2) {
+		if (option_verbose > 2)
 			ast_verbose(VERBOSE_PREFIX_2 "Executing [%s]\n", post_process);
-		}
 		ast_safe_system(post_process);
 	}
 
+out2:
+	ast_mutex_destroy(&spy.lock);
+
+	if (fs)
+		ast_closestream(fs);
+
+out:
+	free(mixmonitor);
+
+	STANDARD_DECREMENT_USECOUNT;
+
 	return NULL;
 }
 
-static void launch_monitor_thread(struct ast_channel *chan, char *filename, unsigned int flags, int readvol , int writevol, char *post_process) 
+static void launch_monitor_thread(struct ast_channel *chan, const char *filename, unsigned int flags,
+				  int readvol, int writevol, const char *post_process) 
 {
 	pthread_attr_t attr;
-	int result = 0;
 	pthread_t thread;
-	struct muxmon *muxmon;
+	struct mixmonitor *mixmonitor;
+	int len;
 
+	len = sizeof(*mixmonitor) + strlen(filename) + 1;
+	if (post_process && !ast_strlen_zero(post_process))
+		len += strlen(post_process) + 1;
 
-	if (!(muxmon = malloc(sizeof(struct muxmon)))) {
+	if (!(mixmonitor = calloc(1, len))) {
 		ast_log(LOG_ERROR, "Memory Error!\n");
 		return;
 	}
 
-	memset(muxmon, 0, sizeof(struct muxmon));
-	muxmon->chan = chan;
-	muxmon->filename = strdup(filename);
-	if(post_process) {
-		muxmon->post_process = strdup(post_process);
+	mixmonitor->chan = chan;
+	mixmonitor->filename = (char *) mixmonitor + sizeof(*mixmonitor);
+	strcpy(mixmonitor->filename, filename);
+	if (post_process && !ast_strlen_zero(post_process)) {
+		mixmonitor->post_process = mixmonitor->filename + strlen(filename) + 1;
+		strcpy(mixmonitor->post_process, post_process);
 	}
-	muxmon->readvol = readvol;
-	muxmon->writevol = writevol;
-	muxmon->flags = flags;
+	mixmonitor->readvol = readvol;
+	mixmonitor->writevol = writevol;
+	mixmonitor->flags = flags;
 
-	result = pthread_attr_init(&attr);
-	pthread_attr_setschedpolicy(&attr, SCHED_RR);
+	pthread_attr_init(&attr);
 	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
-	result = ast_pthread_create(&thread, &attr, muxmon_thread, muxmon);
-	result = pthread_attr_destroy(&attr);
+	ast_pthread_create(&thread, &attr, mixmonitor_thread, mixmonitor);
+	pthread_attr_destroy(&attr);
 }
 
-
-static int muxmon_exec(struct ast_channel *chan, void *data)
+static int mixmonitor_exec(struct ast_channel *chan, void *data)
 {
-	int res = 0, x = 0, readvol = 0, writevol = 0;
+	int x, readvol = 0, writevol = 0;
 	struct localuser *u;
 	struct ast_flags flags = {0};
-	int argc;
-	char *options = NULL,
-		*args,
-		*argv[3],
-		*filename = NULL,
-		*post_process = NULL;
+	char *parse;
+	AST_DECLARE_APP_ARGS(args,
+		AST_APP_ARG(filename);
+		AST_APP_ARG(options);
+		AST_APP_ARG(post_process);
+	);
 	
 	if (ast_strlen_zero(data)) {
-		ast_log(LOG_WARNING, "muxmon requires an argument\n");
+		ast_log(LOG_WARNING, "MixMonitor requires an argument (filename)\n");
 		return -1;
 	}
 
 	LOCAL_USER_ADD(u);
 
-	args = ast_strdupa(data);	
-	if (!args) {
+	if (!(parse = ast_strdupa(data))) {
 		ast_log(LOG_WARNING, "Memory Error!\n");
 		LOCAL_USER_REMOVE(u);
 		return -1;
 	}
 
-	if ((argc = ast_separate_app_args(args, '|', argv, sizeof(argv) / sizeof(argv[0])))) {
-		filename = argv[0];
-		if (argc > 1) {
-			options = argv[1];
-		}
-		if (argc > 2) {
-			post_process = argv[2];
-		}
-	}
+	AST_STANDARD_APP_ARGS(args, parse);
 	
-	if (ast_strlen_zero(filename)) {
+	if (ast_strlen_zero(args.filename)) {
 		ast_log(LOG_WARNING, "Muxmon requires an argument (filename)\n");
 		LOCAL_USER_REMOVE(u);
 		return -1;
 	}
 
-	if (options) {
-		char *opts[3] = {};
-		ast_parseoptions(muxmon_opts, &flags, opts, options);
-
-		if (ast_test_flag(&flags, MUXFLAG_READVOLUME) && opts[0]) {
-			if (sscanf(opts[0], "%d", &x) != 1)
-				ast_log(LOG_NOTICE, "volume must be a number between -4 and 4\n");
-			else {
-				readvol = minmax(x, 4);
-				x = get_volfactor(readvol);
-				readvol = minmax(x, 16);
+	if (args.options) {
+		char *opts[3] = { NULL, };
+
+		ast_parseoptions(mixmonitor_opts, &flags, opts, args.options);
+
+		if (ast_test_flag(&flags, MUXFLAG_READVOLUME)) {
+			if (!opts[0] || ast_strlen_zero(opts[0])) {
+				ast_log(LOG_WARNING, "No volume level was provided for the heard volume ('v') option.\n");
+			} else if ((sscanf(opts[0], "%d", &x) != 1) || (x < -4) || (x > 4)) {
+				ast_log(LOG_NOTICE, "Heard volume must be a number between -4 and 4, not '%s'\n", opts[0]);
+			} else {
+				readvol = get_volfactor(x);
 			}
 		}
 		
-		if (ast_test_flag(&flags, MUXFLAG_WRITEVOLUME) && opts[1]) {
-			if (sscanf(opts[1], "%d", &x) != 1)
-				ast_log(LOG_NOTICE, "volume must be a number between -4 and 4\n");
-			else {
-				writevol = minmax(x, 4);
-				x = get_volfactor(writevol);
-				writevol = minmax(x, 16);
+		if (ast_test_flag(&flags, MUXFLAG_WRITEVOLUME)) {
+			if (!opts[1] || ast_strlen_zero(opts[1])) {
+				ast_log(LOG_WARNING, "No volume level was provided for the spoken volume ('V') option.\n");
+			} else if ((sscanf(opts[1], "%d", &x) != 1) || (x < -4) || (x > 4)) {
+				ast_log(LOG_NOTICE, "Spoken volume must be a number between -4 and 4, not '%s'\n", opts[1]);
+			} else {
+				writevol = get_volfactor(x);
 			}
 		}
-
-		if (ast_test_flag(&flags, MUXFLAG_VOLUME) && opts[2]) {
-			if (sscanf(opts[2], "%d", &x) != 1)
-				ast_log(LOG_NOTICE, "volume must be a number between -4 and 4\n");
-			else {
-				readvol = writevol = minmax(x, 4);
-				x = get_volfactor(readvol);
-				readvol = minmax(x, 16);
-				x = get_volfactor(writevol);
-				writevol = minmax(x, 16);
+		
+		if (ast_test_flag(&flags, MUXFLAG_VOLUME)) {
+			if (!opts[2] || ast_strlen_zero(opts[2])) {
+				ast_log(LOG_WARNING, "No volume level was provided for the combined volume ('W') option.\n");
+			} else if ((sscanf(opts[2], "%d", &x) != 1) || (x < -4) || (x > 4)) {
+				ast_log(LOG_NOTICE, "Combined volume must be a number between -4 and 4, not '%s'\n", opts[2]);
+			} else {
+				readvol = writevol = get_volfactor(x);
 			}
 		}
 	}
-	pbx_builtin_setvar_helper(chan, "MUXMON_FILENAME", filename);
-	launch_monitor_thread(chan, filename, flags.flags, readvol, writevol, post_process);
+
+	/* if not provided an absolute path, use the system-configured monitoring directory */
+	if (args.filename[0] != '/') {
+		char *build;
+
+		build = alloca(strlen(ast_config_AST_MONITOR_DIR) + strlen(args.filename) + 3);
+		sprintf(build, "%s/%s", ast_config_AST_MONITOR_DIR, args.filename);
+		args.filename = build;
+	}
+
+	pbx_builtin_setvar_helper(chan, "MIXMONITOR_FILENAME", args.filename);
+	launch_monitor_thread(chan, args.filename, flags.flags, readvol, writevol, args.post_process);
 
 	LOCAL_USER_REMOVE(u);
-	return res;
-}
 
+	return 0;
+}
 
-static int muxmon_cli(int fd, int argc, char **argv) 
+static int mixmonitor_cli(int fd, int argc, char **argv) 
 {
-	char *op, *chan_name = NULL, *args = NULL;
 	struct ast_channel *chan;
 
-	if (argc > 2) {
-		op = argv[1];
-		chan_name = argv[2];
-
-		if (argv[3]) {
-			args = argv[3];
-		}
+	if (argc < 3)
+		return RESULT_SHOWUSAGE;
 
-		if (!(chan = ast_get_channel_by_name_prefix_locked(chan_name, strlen(chan_name)))) {
-			ast_cli(fd, "Invalid Channel!\n");
-			return -1;
-		}
-		if (!strcasecmp(op, "start")) {
-			muxmon_exec(chan, args);
-		} else if (!strcasecmp(op, "stop")) {
-			struct ast_channel_spy *cptr=NULL;
-			for(cptr=chan->spiers; cptr; cptr=cptr->next) {
-				cptr->status = CHANSPY_DONE;
-			}
-		}
-		ast_mutex_unlock(&chan->lock);
-		return 0;
+	if (!(chan = ast_get_channel_by_name_prefix_locked(argv[2], strlen(argv[2])))) {
+		ast_cli(fd, "No channel matching '%s' found.\n", argv[2]);
+		return RESULT_SUCCESS;
 	}
 
-	ast_cli(fd, "Usage: muxmon <start|stop> <chan_name> <args>\n");
-	return -1;
+	if (!strcasecmp(argv[1], "start"))
+		mixmonitor_exec(chan, argv[3]);
+	else if (!strcasecmp(argv[1], "stop"))
+		ast_channel_spy_stop_by_type(chan, mixmonitor_spy_type);
+
+	ast_mutex_unlock(&chan->lock);
+
+	return RESULT_SUCCESS;
 }
 
 
-static struct ast_cli_entry cli_muxmon = {
-	{ "muxmon", NULL, NULL }, muxmon_cli, 
-	"Execute a monitor command", "muxmon <start|stop> <chan_name> <args>"};
+static struct ast_cli_entry cli_mixmonitor = {
+	{ "mixmonitor", NULL, NULL },
+	mixmonitor_cli, 
+	"Execute a MixMonitor command",
+	"mixmonitor <start|stop> <chan_name> [<args>]"
+};
 
 
 int unload_module(void)
 {
 	int res;
 
-	res = ast_cli_unregister(&cli_muxmon);
+	res = ast_cli_unregister(&cli_mixmonitor);
 	res |= ast_unregister_application(app);
 	
 	STANDARD_HANGUP_LOCALUSERS;
@@ -514,21 +430,23 @@ int load_module(void)
 {
 	int res;
 
-	res = ast_cli_register(&cli_muxmon);
-	res |= ast_register_application(app, muxmon_exec, synopsis, desc);
+	res = ast_cli_register(&cli_mixmonitor);
+	res |= ast_register_application(app, mixmonitor_exec, synopsis, desc);
 
 	return res;
 }
 
 char *description(void)
 {
-	return tdesc;
+	return (char *) tdesc;
 }
 
 int usecount(void)
 {
 	int res;
+
 	STANDARD_USECOUNT(res);
+
 	return res;
 }
 
@@ -536,4 +454,3 @@ char *key()
 {
 	return ASTERISK_GPL_KEY;
 }
-
diff --git a/apps/app_muxmon.c b/apps/app_muxmon.c
index ab8045835..c166c71aa 100755
--- a/apps/app_muxmon.c
+++ b/apps/app_muxmon.c
@@ -1,46 +1,64 @@
 /*
- * Asterisk -- A telephony toolkit for Linux.
- *
+ * Asterisk -- An open source telephony toolkit.
  *
  * Copyright (C) 2005, Anthony Minessale II
+ * Copyright (C) 2005, Digium, Inc.
+ *
+ * Mark Spencer <markster@digium.com>
+ * Kevin P. Fleming <kpfleming@digium.com>
  *
+ * Based on app_muxmon.c provided by
  * Anthony Minessale II <anthmct@yahoo.com>
  *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
  * This program is free software, distributed under the terms of
- * the GNU General Public License
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
  */
 
 /*! \file
  * \brief muxmon() - record a call natively
  */
 
-#include <asterisk/file.h>
-#include <asterisk/logger.h>
-#include <asterisk/channel.h>
-#include <asterisk/pbx.h>
-#include <asterisk/module.h>
-#include <asterisk/lock.h>
-#include <asterisk/cli.h>
-#include <asterisk/options.h>
-#include <asterisk/app.h>
-#include <asterisk/translate.h>
-#include <asterisk/slinfactory.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/file.h"
+#include "asterisk/logger.h"
+#include "asterisk/channel.h"
+#include "asterisk/pbx.h"
+#include "asterisk/module.h"
+#include "asterisk/lock.h"
+#include "asterisk/cli.h"
+#include "asterisk/options.h"
+#include "asterisk/app.h"
+#include "asterisk/linkedlists.h"
+
 #define get_volfactor(x) x ? ((x > 0) ? (1 << x) : ((1 << abs(x)) * -1)) : 0
-#define minmax(x,y) x ? (x > y) ? y : ((x < (y * -1)) ? (y * -1) : x) : 0 
-
-static char *tdesc = "Native Channel Monitoring Module";
-static char *app = "MuxMon";
-static char *synopsis = "Record A Call Natively";
-static char *desc = ""
-"  MuxMon(<file>.<ext>[|<options>[|<command>]])\n\n"
-"Records The audio on the current channel to the specified file.\n\n"
-"Valid Options:\n"
-" b    - Only save audio to the file while the channel is bridged. Note: does\n"
-"        not include conferences\n"
-" a    - Append to the file instead of overwriting it.\n"
+
+static const char *tdesc = "Mixed Audio Monitoring Application";
+static const char *app = "MixMonitor";
+static const char *synopsis = "Record a call and mix the audio during the recording";
+static const char *desc = ""
+"  MixMonitor(<file>.<ext>[|<options>[|<command>]])\n\n"
+"Records the audio on the current channel to the specified file.\n"
+"If the filename is an absolute path, uses that path, otherwise\n"
+"creates the file in the configured monitoring directory from\n"
+"asterisk.conf.\n\n"
+"Valid options:\n"
+" a      - Append to the file instead of overwriting it.\n"
+" b      - Only save audio to the file while the channel is bridged.\n"
+"          Note: does not include conferences.\n"
 " v(<x>) - Adjust the heard volume by a factor of <x> (range -4 to 4)\n"	
 " V(<x>) - Adjust the spoken volume by a factor of <x> (range -4 to 4)\n"	
 " W(<x>) - Adjust the both heard and spoken volumes by a factor of <x>\n"
@@ -48,14 +66,16 @@ static char *desc = ""
 "<command> will be executed when the recording is over\n"
 "Any strings matching ^{X} will be unescaped to ${X} and \n"
 "all variables will be evaluated at that time.\n"
-"The variable MUXMON_FILENAME will contain the filename used to record.\n"
+"The variable MIXMONITOR_FILENAME will contain the filename used to record.\n"
 "";
 
 STANDARD_LOCAL_USER;
 
 LOCAL_USER_DECL;
 
-struct muxmon {
+static const char *mixmonitor_spy_type = "MixMonitor";
+
+struct mixmonitor {
 	struct ast_channel *chan;
 	char *filename;
 	char *post_process;
@@ -64,445 +84,341 @@ struct muxmon {
 	int writevol;
 };
 
-typedef enum {
-    MUXFLAG_RUNNING = (1 << 0),
+enum {
     MUXFLAG_APPEND = (1 << 1),
     MUXFLAG_BRIDGED = (1 << 2),
     MUXFLAG_VOLUME = (1 << 3),
     MUXFLAG_READVOLUME = (1 << 4),
-    MUXFLAG_WRITEVOLUME = (1 << 5)
-} muxflags;
-
+    MUXFLAG_WRITEVOLUME = (1 << 5),
+} mixmonitor_flags;
 
-AST_DECLARE_OPTIONS(muxmon_opts,{
-    ['a'] = { MUXFLAG_APPEND },
+AST_DECLARE_OPTIONS(mixmonitor_opts,{
+	['a'] = { MUXFLAG_APPEND },
 	['b'] = { MUXFLAG_BRIDGED },
 	['v'] = { MUXFLAG_READVOLUME, 1 },
 	['V'] = { MUXFLAG_WRITEVOLUME, 2 },
 	['W'] = { MUXFLAG_VOLUME, 3 },
 });
 
-
 static void stopmon(struct ast_channel *chan, struct ast_channel_spy *spy) 
 {
-	struct ast_channel_spy *cptr=NULL, *prev=NULL;
-	int count = 0;
-
-	if (chan) {
-		while(ast_mutex_trylock(&chan->lock)) {
-			if (chan->spiers == spy) {
-				chan->spiers = NULL;
-				return;
-			}
-			count++;
-			if (count > 10) {
-				return;
-			}
-			sched_yield();
-		}
-		
-		for(cptr=chan->spiers; cptr; cptr=cptr->next) {
-			if (cptr == spy) {
-				if (prev) {
-					prev->next = cptr->next;
-					cptr->next = NULL;
-				} else
-					chan->spiers = NULL;
-			}
-			prev = cptr;
-		}
+	/* If our status has changed, then the channel we're spying on is gone....
+	   DON'T TOUCH IT!!!  RUN AWAY!!! */
+	if (spy->status != CHANSPY_RUNNING)
+		return;
 
-		ast_mutex_unlock(&chan->lock);
-	}
+	if (!chan)
+		return;
+
+	ast_mutex_lock(&chan->lock);
+	ast_channel_spy_remove(chan, spy);
+	ast_mutex_unlock(&chan->lock);
 }
 
-static void startmon(struct ast_channel *chan, struct ast_channel_spy *spy) 
+static int startmon(struct ast_channel *chan, struct ast_channel_spy *spy) 
 {
-
-	struct ast_channel_spy *cptr=NULL;
 	struct ast_channel *peer;
+	int res;
 
-	if (chan) {
-		ast_mutex_lock(&chan->lock);
-		if (chan->spiers) {
-			for(cptr=chan->spiers;cptr->next;cptr=cptr->next);
-			cptr->next = spy;
-		} else {
-			chan->spiers = spy;
-		}
-		ast_mutex_unlock(&chan->lock);
+	if (!chan)
+		return -1;
+
+	ast_mutex_lock(&chan->lock);
+	res = ast_channel_spy_add(chan, spy);
+	ast_mutex_unlock(&chan->lock);
 		
-		if (ast_test_flag(chan, AST_FLAG_NBRIDGE) && (peer = ast_bridged_channel(chan))) {
-			ast_softhangup(peer, AST_SOFTHANGUP_UNBRIDGE);	
-		}
-	}
-}
+	if (!res && ast_test_flag(chan, AST_FLAG_NBRIDGE) && (peer = ast_bridged_channel(chan)))
+		ast_softhangup(peer, AST_SOFTHANGUP_UNBRIDGE);	
 
-static int spy_queue_translate(struct ast_channel_spy *spy,
-							   struct ast_slinfactory *slinfactory0,
-							   struct ast_slinfactory *slinfactory1)
-{
-	int res = 0;
-	struct ast_frame *f;
-	
-	ast_mutex_lock(&spy->lock);
-	while((f = spy->queue[0])) {
-		spy->queue[0] = f->next;
-		ast_slinfactory_feed(slinfactory0, f);
-		ast_frfree(f);
-	}
-	ast_mutex_unlock(&spy->lock);
-	ast_mutex_lock(&spy->lock);
-	while((f = spy->queue[1])) {
-		spy->queue[1] = f->next;
-		ast_slinfactory_feed(slinfactory1, f);
-		ast_frfree(f);
-	}
-	ast_mutex_unlock(&spy->lock);
 	return res;
 }
 
-static void *muxmon_thread(void *obj) 
-{
+#define SAMPLES_PER_FRAME 160
 
-	int len0 = 0, len1 = 0, samp0 = 0, samp1 = 0, framelen, maxsamp = 0, x = 0;
-	short buf0[1280], buf1[1280], buf[1280];
-	struct ast_frame frame;
-	struct muxmon *muxmon = obj;
+static void *mixmonitor_thread(void *obj) 
+{
+	struct mixmonitor *mixmonitor = obj;
 	struct ast_channel_spy spy;
 	struct ast_filestream *fs = NULL;
 	char *ext, *name;
 	unsigned int oflags;
-	struct ast_slinfactory slinfactory[2];
+	struct ast_frame *f;
 	char post_process[1024] = "";
 	
-	name = ast_strdupa(muxmon->chan->name);
+	STANDARD_INCREMENT_USECOUNT;
 
-	framelen = 320;
-	frame.frametype = AST_FRAME_VOICE;
-	frame.subclass = AST_FORMAT_SLINEAR;
-	frame.data = buf;
-	ast_set_flag(muxmon, MUXFLAG_RUNNING);
-	oflags = O_CREAT|O_WRONLY;
-	ast_slinfactory_init(&slinfactory[0]);
-	ast_slinfactory_init(&slinfactory[1]);
-	
+	name = ast_strdupa(mixmonitor->chan->name);
 
-
-	/* for efficiency, use a flag to bypass volume logic when it's not needed */
-	if (muxmon->readvol || muxmon->writevol) {
-		ast_set_flag(muxmon, MUXFLAG_VOLUME);
-	}
-
-	if ((ext = strchr(muxmon->filename, '.'))) {
+	oflags = O_CREAT|O_WRONLY;
+	oflags |= ast_test_flag(mixmonitor, MUXFLAG_APPEND) ? O_APPEND : O_TRUNC;
+		
+	if ((ext = strchr(mixmonitor->filename, '.'))) {
 		*(ext++) = '\0';
 	} else {
 		ext = "raw";
 	}
 
+	fs = ast_writefile(mixmonitor->filename, ext, NULL, oflags, 0, 0644);
+	if (!fs) {
+		ast_log(LOG_ERROR, "Cannot open %s.%s\n", mixmonitor->filename, ext);
+		goto out;
+	}
+
+	if (ast_test_flag(mixmonitor, MUXFLAG_APPEND))
+		ast_seekstream(fs, 0, SEEK_END);
+	
 	memset(&spy, 0, sizeof(spy));
+	ast_set_flag(&spy, CHANSPY_FORMAT_AUDIO);
+	ast_set_flag(&spy, CHANSPY_MIXAUDIO);
+	spy.type = mixmonitor_spy_type;
 	spy.status = CHANSPY_RUNNING;
+	spy.read_queue.format = AST_FORMAT_SLINEAR;
+	spy.write_queue.format = AST_FORMAT_SLINEAR;
+	if (mixmonitor->readvol) {
+		ast_set_flag(&spy, CHANSPY_READ_VOLADJUST);
+		spy.read_vol_adjustment = mixmonitor->readvol;
+	}
+	if (mixmonitor->writevol) {
+		ast_set_flag(&spy, CHANSPY_WRITE_VOLADJUST);
+		spy.write_vol_adjustment = mixmonitor->writevol;
+	}
 	ast_mutex_init(&spy.lock);
-	startmon(muxmon->chan, &spy);
-	if (ast_test_flag(muxmon, MUXFLAG_RUNNING)) {
-		if (option_verbose > 1) {
-			ast_verbose(VERBOSE_PREFIX_2 "Begin Muxmon Recording %s\n", name);
-		}
 
-		oflags |= ast_test_flag(muxmon, MUXFLAG_APPEND) ? O_APPEND : O_TRUNC;
-		
-		if (!(fs = ast_writefile(muxmon->filename, ext, NULL, oflags, 0, 0644))) {
-			ast_log(LOG_ERROR, "Cannot open %s\n", muxmon->filename);
-			spy.status = CHANSPY_DONE;
-		}  else {
+	if (startmon(mixmonitor->chan, &spy)) {
+		ast_log(LOG_WARNING, "Unable to add '%s' spy to channel '%s'\n",
+			spy.type, mixmonitor->chan->name);
+		goto out2;
+	}
 
-			if (ast_test_flag(muxmon, MUXFLAG_APPEND)) {
-				ast_seekstream(fs, 0, SEEK_END);
-			}
+	if (option_verbose > 1)
+		ast_verbose(VERBOSE_PREFIX_2 "Begin MixMonitor Recording %s\n", name);
+	
+	while (1) {
+		struct ast_frame *next;
+		int write;
+
+		ast_mutex_lock(&spy.lock);
 
-			while (ast_test_flag(muxmon, MUXFLAG_RUNNING)) {
-				samp0 = samp1 = len0 = len1 = 0;
-
-				if (ast_check_hangup(muxmon->chan) || spy.status != CHANSPY_RUNNING) {
-					ast_clear_flag(muxmon, MUXFLAG_RUNNING);
-					break;
-				}
-
-				if (ast_test_flag(muxmon, MUXFLAG_BRIDGED) && !ast_bridged_channel(muxmon->chan)) {
-					usleep(1000);
-					sched_yield();
-					continue;
-				}
-				
-				spy_queue_translate(&spy, &slinfactory[0], &slinfactory[1]);
-				
-				if (slinfactory[0].size < framelen || slinfactory[1].size < framelen) {
-					usleep(1000);
-					sched_yield();
-					continue;
-				}
-
-				if ((len0 = ast_slinfactory_read(&slinfactory[0], buf0, framelen))) {
-					samp0 = len0 / 2;
-				}
-				if((len1 = ast_slinfactory_read(&slinfactory[1], buf1, framelen))) {
-					samp1 = len1 / 2;
-				}
-				
-				if (ast_test_flag(muxmon, MUXFLAG_VOLUME)) {
-					if (samp0 && muxmon->readvol > 0) {
-						for(x=0; x < samp0 / 2; x++) {
-							buf0[x] *= muxmon->readvol;
-						}
-					} else if (samp0 && muxmon->readvol < 0) {
-						for(x=0; x < samp0 / 2; x++) {
-							buf0[x] /= muxmon->readvol;
-						}
-					}
-					if (samp1 && muxmon->writevol > 0) {
-						for(x=0; x < samp1 / 2; x++) {
-							buf1[x] *= muxmon->writevol;
-						}
-					} else if (muxmon->writevol < 0) {
-						for(x=0; x < samp1 / 2; x++) {
-							buf1[x] /= muxmon->writevol;
-						}
-					}
-				}
-				
-				maxsamp = (samp0 > samp1) ? samp0 : samp1;
-
-				if (samp0 && samp1) {
-					for(x=0; x < maxsamp; x++) {
-						if (x < samp0 && x < samp1) {
-							buf[x] = buf0[x] + buf1[x];
-						} else if (x < samp0) {
-							buf[x] = buf0[x];
-						} else if (x < samp1) {
-							buf[x] = buf1[x];
-						}
-					}
-				} else if(samp0) {
-					memcpy(buf, buf0, len0);
-					x = samp0;
-				} else if(samp1) {
-					memcpy(buf, buf1, len1);
-					x = samp1;
-				}
-
-				frame.samples = x;
-				frame.datalen = x * 2;
-				ast_writestream(fs, &frame);
+		ast_channel_spy_trigger_wait(&spy);
 		
-				usleep(1000);
-				sched_yield();
+		if (ast_check_hangup(mixmonitor->chan) || spy.status != CHANSPY_RUNNING) {
+			ast_mutex_unlock(&spy.lock);
+			break;
+		}
+		
+		while (1) {
+			if (!(f = ast_channel_spy_read_frame(&spy, SAMPLES_PER_FRAME)))
+				break;
+
+			write = (!ast_test_flag(mixmonitor, MUXFLAG_BRIDGED) ||
+				 ast_bridged_channel(mixmonitor->chan));
+
+			/* it is possible for ast_channel_spy_read_frame() to return a chain
+			   of frames if a queue flush was necessary, so process them
+			*/
+			for (; f; f = next) {
+				next = f->next;
+				if (write)
+					ast_writestream(fs, f);
+				ast_frfree(f);
 			}
 		}
-	}
 
-	if (muxmon->post_process) {
+		ast_mutex_unlock(&spy.lock);
+	}
+	
+	if (mixmonitor->post_process) {
 		char *p;
-		for(p = muxmon->post_process; *p ; p++) {
+
+		for (p = mixmonitor->post_process; *p ; p++) {
 			if (*p == '^' && *(p+1) == '{') {
 				*p = '$';
 			}
 		}
-		pbx_substitute_variables_helper(muxmon->chan, muxmon->post_process, post_process, sizeof(post_process) - 1);
-		free(muxmon->post_process);
-		muxmon->post_process = NULL;
+		pbx_substitute_variables_helper(mixmonitor->chan, mixmonitor->post_process, post_process, sizeof(post_process) - 1);
 	}
 
-	stopmon(muxmon->chan, &spy);
-	if (option_verbose > 1) {
-		ast_verbose(VERBOSE_PREFIX_2 "Finished Recording %s\n", name);
-	}
-	ast_mutex_destroy(&spy.lock);
-	
-	if(fs) {
-		ast_closestream(fs);
-	}
-	
-	ast_slinfactory_destroy(&slinfactory[0]);
-	ast_slinfactory_destroy(&slinfactory[1]);
+	stopmon(mixmonitor->chan, &spy);
 
-	if (muxmon) {
-		if (muxmon->filename) {
-			free(muxmon->filename);
-		}
-		free(muxmon);
-	}
+	if (option_verbose > 1)
+		ast_verbose(VERBOSE_PREFIX_2 "End MixMonitor Recording %s\n", name);
 
 	if (!ast_strlen_zero(post_process)) {
-		if (option_verbose > 2) {
+		if (option_verbose > 2)
 			ast_verbose(VERBOSE_PREFIX_2 "Executing [%s]\n", post_process);
-		}
 		ast_safe_system(post_process);
 	}
 
+out2:
+	ast_mutex_destroy(&spy.lock);
+
+	if (fs)
+		ast_closestream(fs);
+
+out:
+	free(mixmonitor);
+
+	STANDARD_DECREMENT_USECOUNT;
+
 	return NULL;
 }
 
-static void launch_monitor_thread(struct ast_channel *chan, char *filename, unsigned int flags, int readvol , int writevol, char *post_process) 
+static void launch_monitor_thread(struct ast_channel *chan, const char *filename, unsigned int flags,
+				  int readvol, int writevol, const char *post_process) 
 {
 	pthread_attr_t attr;
-	int result = 0;
 	pthread_t thread;
-	struct muxmon *muxmon;
+	struct mixmonitor *mixmonitor;
+	int len;
 
+	len = sizeof(*mixmonitor) + strlen(filename) + 1;
+	if (post_process && !ast_strlen_zero(post_process))
+		len += strlen(post_process) + 1;
 
-	if (!(muxmon = malloc(sizeof(struct muxmon)))) {
+	if (!(mixmonitor = calloc(1, len))) {
 		ast_log(LOG_ERROR, "Memory Error!\n");
 		return;
 	}
 
-	memset(muxmon, 0, sizeof(struct muxmon));
-	muxmon->chan = chan;
-	muxmon->filename = strdup(filename);
-	if(post_process) {
-		muxmon->post_process = strdup(post_process);
+	mixmonitor->chan = chan;
+	mixmonitor->filename = (char *) mixmonitor + sizeof(*mixmonitor);
+	strcpy(mixmonitor->filename, filename);
+	if (post_process && !ast_strlen_zero(post_process)) {
+		mixmonitor->post_process = mixmonitor->filename + strlen(filename) + 1;
+		strcpy(mixmonitor->post_process, post_process);
 	}
-	muxmon->readvol = readvol;
-	muxmon->writevol = writevol;
-	muxmon->flags = flags;
+	mixmonitor->readvol = readvol;
+	mixmonitor->writevol = writevol;
+	mixmonitor->flags = flags;
 
-	result = pthread_attr_init(&attr);
-	pthread_attr_setschedpolicy(&attr, SCHED_RR);
+	pthread_attr_init(&attr);
 	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
-	result = ast_pthread_create(&thread, &attr, muxmon_thread, muxmon);
-	result = pthread_attr_destroy(&attr);
+	ast_pthread_create(&thread, &attr, mixmonitor_thread, mixmonitor);
+	pthread_attr_destroy(&attr);
 }
 
-
-static int muxmon_exec(struct ast_channel *chan, void *data)
+static int mixmonitor_exec(struct ast_channel *chan, void *data)
 {
-	int res = 0, x = 0, readvol = 0, writevol = 0;
+	int x, readvol = 0, writevol = 0;
 	struct localuser *u;
 	struct ast_flags flags = {0};
-	int argc;
-	char *options = NULL,
-		*args,
-		*argv[3],
-		*filename = NULL,
-		*post_process = NULL;
+	char *parse;
+	AST_DECLARE_APP_ARGS(args,
+		AST_APP_ARG(filename);
+		AST_APP_ARG(options);
+		AST_APP_ARG(post_process);
+	);
 	
 	if (ast_strlen_zero(data)) {
-		ast_log(LOG_WARNING, "muxmon requires an argument\n");
+		ast_log(LOG_WARNING, "MixMonitor requires an argument (filename)\n");
 		return -1;
 	}
 
 	LOCAL_USER_ADD(u);
 
-	args = ast_strdupa(data);	
-	if (!args) {
+	if (!(parse = ast_strdupa(data))) {
 		ast_log(LOG_WARNING, "Memory Error!\n");
 		LOCAL_USER_REMOVE(u);
 		return -1;
 	}
 
-	if ((argc = ast_separate_app_args(args, '|', argv, sizeof(argv) / sizeof(argv[0])))) {
-		filename = argv[0];
-		if (argc > 1) {
-			options = argv[1];
-		}
-		if (argc > 2) {
-			post_process = argv[2];
-		}
-	}
+	AST_STANDARD_APP_ARGS(args, parse);
 	
-	if (ast_strlen_zero(filename)) {
+	if (ast_strlen_zero(args.filename)) {
 		ast_log(LOG_WARNING, "Muxmon requires an argument (filename)\n");
 		LOCAL_USER_REMOVE(u);
 		return -1;
 	}
 
-	if (options) {
-		char *opts[3] = {};
-		ast_parseoptions(muxmon_opts, &flags, opts, options);
-
-		if (ast_test_flag(&flags, MUXFLAG_READVOLUME) && opts[0]) {
-			if (sscanf(opts[0], "%d", &x) != 1)
-				ast_log(LOG_NOTICE, "volume must be a number between -4 and 4\n");
-			else {
-				readvol = minmax(x, 4);
-				x = get_volfactor(readvol);
-				readvol = minmax(x, 16);
+	if (args.options) {
+		char *opts[3] = { NULL, };
+
+		ast_parseoptions(mixmonitor_opts, &flags, opts, args.options);
+
+		if (ast_test_flag(&flags, MUXFLAG_READVOLUME)) {
+			if (!opts[0] || ast_strlen_zero(opts[0])) {
+				ast_log(LOG_WARNING, "No volume level was provided for the heard volume ('v') option.\n");
+			} else if ((sscanf(opts[0], "%d", &x) != 1) || (x < -4) || (x > 4)) {
+				ast_log(LOG_NOTICE, "Heard volume must be a number between -4 and 4, not '%s'\n", opts[0]);
+			} else {
+				readvol = get_volfactor(x);
 			}
 		}
 		
-		if (ast_test_flag(&flags, MUXFLAG_WRITEVOLUME) && opts[1]) {
-			if (sscanf(opts[1], "%d", &x) != 1)
-				ast_log(LOG_NOTICE, "volume must be a number between -4 and 4\n");
-			else {
-				writevol = minmax(x, 4);
-				x = get_volfactor(writevol);
-				writevol = minmax(x, 16);
+		if (ast_test_flag(&flags, MUXFLAG_WRITEVOLUME)) {
+			if (!opts[1] || ast_strlen_zero(opts[1])) {
+				ast_log(LOG_WARNING, "No volume level was provided for the spoken volume ('V') option.\n");
+			} else if ((sscanf(opts[1], "%d", &x) != 1) || (x < -4) || (x > 4)) {
+				ast_log(LOG_NOTICE, "Spoken volume must be a number between -4 and 4, not '%s'\n", opts[1]);
+			} else {
+				writevol = get_volfactor(x);
 			}
 		}
-
-		if (ast_test_flag(&flags, MUXFLAG_VOLUME) && opts[2]) {
-			if (sscanf(opts[2], "%d", &x) != 1)
-				ast_log(LOG_NOTICE, "volume must be a number between -4 and 4\n");
-			else {
-				readvol = writevol = minmax(x, 4);
-				x = get_volfactor(readvol);
-				readvol = minmax(x, 16);
-				x = get_volfactor(writevol);
-				writevol = minmax(x, 16);
+		
+		if (ast_test_flag(&flags, MUXFLAG_VOLUME)) {
+			if (!opts[2] || ast_strlen_zero(opts[2])) {
+				ast_log(LOG_WARNING, "No volume level was provided for the combined volume ('W') option.\n");
+			} else if ((sscanf(opts[2], "%d", &x) != 1) || (x < -4) || (x > 4)) {
+				ast_log(LOG_NOTICE, "Combined volume must be a number between -4 and 4, not '%s'\n", opts[2]);
+			} else {
+				readvol = writevol = get_volfactor(x);
 			}
 		}
 	}
-	pbx_builtin_setvar_helper(chan, "MUXMON_FILENAME", filename);
-	launch_monitor_thread(chan, filename, flags.flags, readvol, writevol, post_process);
+
+	/* if not provided an absolute path, use the system-configured monitoring directory */
+	if (args.filename[0] != '/') {
+		char *build;
+
+		build = alloca(strlen(ast_config_AST_MONITOR_DIR) + strlen(args.filename) + 3);
+		sprintf(build, "%s/%s", ast_config_AST_MONITOR_DIR, args.filename);
+		args.filename = build;
+	}
+
+	pbx_builtin_setvar_helper(chan, "MIXMONITOR_FILENAME", args.filename);
+	launch_monitor_thread(chan, args.filename, flags.flags, readvol, writevol, args.post_process);
 
 	LOCAL_USER_REMOVE(u);
-	return res;
-}
 
+	return 0;
+}
 
-static int muxmon_cli(int fd, int argc, char **argv) 
+static int mixmonitor_cli(int fd, int argc, char **argv) 
 {
-	char *op, *chan_name = NULL, *args = NULL;
 	struct ast_channel *chan;
 
-	if (argc > 2) {
-		op = argv[1];
-		chan_name = argv[2];
-
-		if (argv[3]) {
-			args = argv[3];
-		}
+	if (argc < 3)
+		return RESULT_SHOWUSAGE;
 
-		if (!(chan = ast_get_channel_by_name_prefix_locked(chan_name, strlen(chan_name)))) {
-			ast_cli(fd, "Invalid Channel!\n");
-			return -1;
-		}
-		if (!strcasecmp(op, "start")) {
-			muxmon_exec(chan, args);
-		} else if (!strcasecmp(op, "stop")) {
-			struct ast_channel_spy *cptr=NULL;
-			for(cptr=chan->spiers; cptr; cptr=cptr->next) {
-				cptr->status = CHANSPY_DONE;
-			}
-		}
-		ast_mutex_unlock(&chan->lock);
-		return 0;
+	if (!(chan = ast_get_channel_by_name_prefix_locked(argv[2], strlen(argv[2])))) {
+		ast_cli(fd, "No channel matching '%s' found.\n", argv[2]);
+		return RESULT_SUCCESS;
 	}
 
-	ast_cli(fd, "Usage: muxmon <start|stop> <chan_name> <args>\n");
-	return -1;
+	if (!strcasecmp(argv[1], "start"))
+		mixmonitor_exec(chan, argv[3]);
+	else if (!strcasecmp(argv[1], "stop"))
+		ast_channel_spy_stop_by_type(chan, mixmonitor_spy_type);
+
+	ast_mutex_unlock(&chan->lock);
+
+	return RESULT_SUCCESS;
 }
 
 
-static struct ast_cli_entry cli_muxmon = {
-	{ "muxmon", NULL, NULL }, muxmon_cli, 
-	"Execute a monitor command", "muxmon <start|stop> <chan_name> <args>"};
+static struct ast_cli_entry cli_mixmonitor = {
+	{ "mixmonitor", NULL, NULL },
+	mixmonitor_cli, 
+	"Execute a MixMonitor command",
+	"mixmonitor <start|stop> <chan_name> [<args>]"
+};
 
 
 int unload_module(void)
 {
 	int res;
 
-	res = ast_cli_unregister(&cli_muxmon);
+	res = ast_cli_unregister(&cli_mixmonitor);
 	res |= ast_unregister_application(app);
 	
 	STANDARD_HANGUP_LOCALUSERS;
@@ -514,21 +430,23 @@ int load_module(void)
 {
 	int res;
 
-	res = ast_cli_register(&cli_muxmon);
-	res |= ast_register_application(app, muxmon_exec, synopsis, desc);
+	res = ast_cli_register(&cli_mixmonitor);
+	res |= ast_register_application(app, mixmonitor_exec, synopsis, desc);
 
 	return res;
 }
 
 char *description(void)
 {
-	return tdesc;
+	return (char *) tdesc;
 }
 
 int usecount(void)
 {
 	int res;
+
 	STANDARD_USECOUNT(res);
+
 	return res;
 }
 
@@ -536,4 +454,3 @@ char *key()
 {
 	return ASTERISK_GPL_KEY;
 }
-
diff --git a/channel.c b/channel.c
index 85692e7d6..c3f3d0384 100755
--- a/channel.c
+++ b/channel.c
@@ -71,6 +71,17 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/transcap.h"
 #include "asterisk/devicestate.h"
 
+struct channel_spy_trans {
+	int last_format;
+	struct ast_trans_pvt *path;
+};
+
+struct ast_channel_spy_list {
+	struct channel_spy_trans read_translator;
+	struct channel_spy_trans write_translator;
+	AST_LIST_HEAD_NOLOCK(, ast_channel_spy) list;
+};
+
 /* uncomment if you have problems with 'monitoring' synchronized files */
 #if 0
 #define MONITOR_CONSTANT_DELAY
@@ -931,10 +942,8 @@ void ast_channel_free(struct ast_channel *chan)
 	/* loop over the variables list, freeing all data and deleting list items */
 	/* no need to lock the list, as the channel is already locked */
 	
-	while (!AST_LIST_EMPTY(headp)) {           /* List Deletion. */
-	            vardata = AST_LIST_REMOVE_HEAD(headp, entries);
-	            ast_var_delete(vardata);
-	}
+	while ((vardata = AST_LIST_REMOVE_HEAD(headp, entries)))
+		ast_var_delete(vardata);
 
 	free(chan);
 	ast_mutex_unlock(&chlock);
@@ -942,19 +951,134 @@ void ast_channel_free(struct ast_channel *chan)
 	ast_device_state_changed_literal(name);
 }
 
-static void ast_spy_detach(struct ast_channel *chan) 
+int ast_channel_spy_add(struct ast_channel *chan, struct ast_channel_spy *spy)
 {
-	struct ast_channel_spy *chanspy;
+	if (!ast_test_flag(spy, CHANSPY_FORMAT_AUDIO)) {
+		ast_log(LOG_WARNING, "Could not add channel spy '%s' to channel '%s', only audio format spies are supported.\n",
+			spy->type, chan->name);
+		return -1;
+	}
 
-	/* Marking the spies as done is sufficient.  Chanspy or spy users will get the picture. */
-	for (chanspy = chan->spiers; chanspy; chanspy = chanspy->next) {
-		if (chanspy->status == CHANSPY_RUNNING) {
-			chanspy->status = CHANSPY_DONE;
+	if (ast_test_flag(spy, CHANSPY_READ_VOLADJUST) && (spy->read_queue.format != AST_FORMAT_SLINEAR)) {
+		ast_log(LOG_WARNING, "Cannot provide volume adjustment on '%s' format spies\n",
+			ast_getformatname(spy->read_queue.format));
+		return -1;
+	}
+
+	if (ast_test_flag(spy, CHANSPY_WRITE_VOLADJUST) && (spy->write_queue.format != AST_FORMAT_SLINEAR)) {
+		ast_log(LOG_WARNING, "Cannot provide volume adjustment on '%s' format spies\n",
+			ast_getformatname(spy->write_queue.format));
+		return -1;
+	}
+
+	if (ast_test_flag(spy, CHANSPY_MIXAUDIO) &&
+	    ((spy->read_queue.format != AST_FORMAT_SLINEAR) ||
+	     (spy->write_queue.format != AST_FORMAT_SLINEAR))) {
+		ast_log(LOG_WARNING, "Cannot provide audio mixing on '%s'-'%s' format spies\n",
+			ast_getformatname(spy->read_queue.format), ast_getformatname(spy->write_queue.format));
+		return -1;
+	}
+
+	if (!chan->spies) {
+		if (!(chan->spies = calloc(1, sizeof(*chan->spies)))) {
+			ast_log(LOG_WARNING, "Memory allocation failure\n");
+			return -1;
 		}
+
+		AST_LIST_HEAD_INIT_NOLOCK(&chan->spies->list);
+		AST_LIST_INSERT_HEAD(&chan->spies->list, spy, list);
+	} else {
+		AST_LIST_INSERT_TAIL(&chan->spies->list, spy, list);
 	}
 
-	chan->spiers = NULL;
-	return;
+	if (ast_test_flag(spy, CHANSPY_TRIGGER_MODE) != CHANSPY_TRIGGER_NONE) {
+		ast_cond_init(&spy->trigger, NULL);
+		ast_set_flag(spy, CHANSPY_TRIGGER_READ);
+		ast_clear_flag(spy, CHANSPY_TRIGGER_WRITE);
+	}
+
+	ast_log(LOG_DEBUG, "Spy %s added to channel %s\n",
+		spy->type, chan->name);
+
+	return 0;
+}
+
+void ast_channel_spy_stop_by_type(struct ast_channel *chan, const char *type)
+{
+	struct ast_channel_spy *spy;
+	
+	if (!chan->spies)
+		return;
+
+	AST_LIST_TRAVERSE(&chan->spies->list, spy, list) {
+		if ((spy->type == type) && (spy->status == CHANSPY_RUNNING))
+			spy->status = CHANSPY_DONE;
+	}
+}
+
+void ast_channel_spy_trigger_wait(struct ast_channel_spy *spy)
+{
+	ast_cond_wait(&spy->trigger, &spy->lock);
+}
+
+void ast_channel_spy_remove(struct ast_channel *chan, struct ast_channel_spy *spy)
+{
+	struct ast_frame *f;
+
+	if (!chan->spies)
+		return;
+
+	AST_LIST_REMOVE(&chan->spies->list, spy, list);
+
+	ast_mutex_lock(&spy->lock);
+
+	for (f = spy->read_queue.head; f; f = spy->read_queue.head) {
+		spy->read_queue.head = f->next;
+		ast_frfree(f);
+	}
+	for (f = spy->write_queue.head; f; f = spy->write_queue.head) {
+		spy->write_queue.head = f->next;
+		ast_frfree(f);
+	}
+
+	if (ast_test_flag(spy, CHANSPY_TRIGGER_MODE) != CHANSPY_TRIGGER_NONE)
+		ast_cond_destroy(&spy->trigger);
+
+	ast_mutex_unlock(&spy->lock);
+
+	ast_log(LOG_DEBUG, "Spy %s removed from channel %s\n",
+		spy->type, chan->name);
+
+	if (AST_LIST_EMPTY(&chan->spies->list)) {
+		if (chan->spies->read_translator.path)
+			ast_translator_free_path(chan->spies->read_translator.path);
+		if (chan->spies->write_translator.path)
+			ast_translator_free_path(chan->spies->write_translator.path);
+		free(chan->spies);
+		chan->spies = NULL;
+	}
+}
+
+static void detach_spies(struct ast_channel *chan) 
+{
+	struct ast_channel_spy *spy;
+
+	if (!chan->spies)
+		return;
+
+	/* Marking the spies as done is sufficient.  Chanspy or spy users will get the picture. */
+	AST_LIST_TRAVERSE(&chan->spies->list, spy, list) {
+		ast_mutex_lock(&spy->lock);
+		if (spy->status == CHANSPY_RUNNING)
+			spy->status = CHANSPY_DONE;
+		if (ast_test_flag(spy, CHANSPY_TRIGGER_MODE) != CHANSPY_TRIGGER_NONE)
+			ast_cond_signal(&spy->trigger);
+		ast_mutex_unlock(&spy->lock);
+	}
+
+	AST_LIST_TRAVERSE_SAFE_BEGIN(&chan->spies->list, spy, list)
+		ast_channel_spy_remove(chan, spy);
+	AST_LIST_TRAVERSE_SAFE_END;
 }
 
 /*--- ast_softhangup_nolock: Softly hangup a channel, don't lock */
@@ -983,40 +1107,136 @@ int ast_softhangup(struct ast_channel *chan, int cause)
 	return res;
 }
 
-static void ast_queue_spy_frame(struct ast_channel_spy *spy, struct ast_frame *f, int pos) 
+enum spy_direction {
+	SPY_READ,
+	SPY_WRITE,
+};
+
+#define SPY_QUEUE_SAMPLE_LIMIT 4000			/* half of one second */
+
+static void queue_frame_to_spies(struct ast_channel *chan, struct ast_frame *f, enum spy_direction dir)
 {
-	struct ast_frame *tmpf = NULL;
-	int count = 0;
+	struct ast_frame *translated_frame = NULL;
+	struct ast_channel_spy *spy;
+	struct ast_channel_spy_queue *queue;
+	struct ast_channel_spy_queue *other_queue;
+	struct channel_spy_trans *trans;
+	struct ast_frame *last;
 
-	ast_mutex_lock(&spy->lock);
-	for (tmpf=spy->queue[pos]; tmpf && tmpf->next; tmpf=tmpf->next) {
-		count++;
-	}
-	if (count > 1000) {
-		struct ast_frame *freef, *headf;
-
-		ast_log(LOG_ERROR, "Too many frames queued at once, flushing cache.\n");
-		headf = spy->queue[pos];
-		/* deref the queue right away so it looks empty */
-		spy->queue[pos] = NULL;
-		tmpf = headf;
-		/* free the wasted frames */
-		while (tmpf) {
-			freef = tmpf;
-			tmpf = tmpf->next;
-			ast_frfree(freef);
+	trans = (dir == SPY_READ) ? &chan->spies->read_translator : &chan->spies->write_translator;
+
+	AST_LIST_TRAVERSE(&chan->spies->list, spy, list) {
+		ast_mutex_lock(&spy->lock);
+
+		queue = (dir == SPY_READ) ? &spy->read_queue : &spy->write_queue;
+
+		if ((queue->format == AST_FORMAT_SLINEAR) && (f->subclass != AST_FORMAT_SLINEAR)) {
+			if (!translated_frame) {
+				if (trans->path && (trans->last_format != f->subclass)) {
+					ast_translator_free_path(trans->path);
+					trans->path = NULL;
+				}
+				if (!trans->path) {
+					ast_log(LOG_DEBUG, "Building translator from %s to SLINEAR for spies on channel %s\n",
+						ast_getformatname(f->subclass), chan->name);
+					if ((trans->path = ast_translator_build_path(AST_FORMAT_SLINEAR, f->subclass)) == NULL) {
+						ast_log(LOG_WARNING, "Cannot build a path from %s to %s\n",
+							ast_getformatname(f->subclass), ast_getformatname(AST_FORMAT_SLINEAR));
+						ast_mutex_unlock(&spy->lock);
+						continue;
+					} else {
+						trans->last_format = f->subclass;
+					}
+				}
+				translated_frame = ast_translate(trans->path, f, 0);
+			}
+
+			for (last = queue->head; last && last->next; last = last->next);
+			if (last)
+				last->next = ast_frdup(translated_frame);
+			else
+				queue->head = ast_frdup(translated_frame);
+		} else {
+			if (f->subclass != queue->format) {
+				ast_log(LOG_WARNING, "Spy '%s' on channel '%s' wants format '%s', but frame is '%s', dropping\n",
+					spy->type, chan->name,
+					ast_getformatname(queue->format), ast_getformatname(f->subclass));
+				ast_mutex_unlock(&spy->lock);
+				continue;
+			}
+
+			for (last = queue->head; last && last->next; last = last->next);
+			if (last)
+				last->next = ast_frdup(f);
+			else
+				queue->head = ast_frdup(f);
 		}
-		ast_mutex_unlock(&spy->lock);
-		return;
-	}
 
-	if (tmpf) {
-		tmpf->next = ast_frdup(f);
-	} else {
-		spy->queue[pos] = ast_frdup(f);
+		queue->samples += f->samples;
+
+		if (queue->samples > SPY_QUEUE_SAMPLE_LIMIT) {
+			if (ast_test_flag(spy, CHANSPY_TRIGGER_MODE) != CHANSPY_TRIGGER_NONE) {
+				other_queue = (dir == SPY_WRITE) ? &spy->read_queue : &spy->write_queue;
+
+				if (other_queue->samples == 0) {
+					switch (ast_test_flag(spy, CHANSPY_TRIGGER_MODE)) {
+					case CHANSPY_TRIGGER_READ:
+						if (dir == SPY_WRITE) {
+							ast_set_flag(spy, CHANSPY_TRIGGER_WRITE);
+							ast_clear_flag(spy, CHANSPY_TRIGGER_READ);
+							if (option_debug)
+								ast_log(LOG_DEBUG, "Switching spy '%s' on '%s' to write-trigger mode\n",
+									spy->type, chan->name);
+						}
+						break;
+					case CHANSPY_TRIGGER_WRITE:
+						if (dir == SPY_READ) {
+							ast_set_flag(spy, CHANSPY_TRIGGER_READ);
+							ast_clear_flag(spy, CHANSPY_TRIGGER_WRITE);
+							if (option_debug)
+								ast_log(LOG_DEBUG, "Switching spy '%s' on '%s' to read-trigger mode\n",
+									spy->type, chan->name);
+						}
+						break;
+					}
+					if (option_debug)
+						ast_log(LOG_DEBUG, "Triggering queue flush for spy '%s' on '%s'\n",
+							spy->type, chan->name);
+					ast_set_flag(spy, CHANSPY_TRIGGER_FLUSH);
+					ast_cond_signal(&spy->trigger);
+					ast_mutex_unlock(&spy->lock);
+					continue;
+				}
+			}
+
+			if (option_debug)
+				ast_log(LOG_DEBUG, "Spy '%s' on channel '%s' %s queue too long, dropping frames\n",
+					spy->type, chan->name, (dir == SPY_READ) ? "read" : "write");
+			while (queue->samples > SPY_QUEUE_SAMPLE_LIMIT) {
+				struct ast_frame *drop = queue->head;
+
+				queue->samples -= drop->samples;
+				queue->head = drop->next;
+				ast_frfree(drop);
+			}
+		} else {
+			switch (ast_test_flag(spy, CHANSPY_TRIGGER_MODE)) {
+			case CHANSPY_TRIGGER_READ:
+				if (dir == SPY_READ)
+					ast_cond_signal(&spy->trigger);
+				break;
+			case CHANSPY_TRIGGER_WRITE:
+				if (dir == SPY_WRITE)
+					ast_cond_signal(&spy->trigger);
+				break;
+			}
+		}
+
+		ast_mutex_unlock(&spy->lock);
 	}
 
-	ast_mutex_unlock(&spy->lock);
+	if (translated_frame)
+		ast_frfree(translated_frame);
 }
 
 static void free_translation(struct ast_channel *clone)
@@ -1040,7 +1260,7 @@ int ast_hangup(struct ast_channel *chan)
 	   if someone is going to masquerade as us */
 	ast_mutex_lock(&chan->lock);
 
-	ast_spy_detach(chan);		/* get rid of spies */
+	detach_spies(chan);		/* get rid of spies */
 
 	if (chan->masq) {
 		if (ast_do_masquerade(chan)) 
@@ -1174,20 +1394,28 @@ static int generator_force(void *data)
 int ast_activate_generator(struct ast_channel *chan, struct ast_generator *gen, void *params)
 {
 	int res = 0;
+
 	ast_mutex_lock(&chan->lock);
+
 	if (chan->generatordata) {
 		if (chan->generator && chan->generator->release)
 			chan->generator->release(chan, chan->generatordata);
 		chan->generatordata = NULL;
 	}
+
 	ast_prod(chan);
-	if ((chan->generatordata = gen->alloc(chan, params))) {
+	if (gen->alloc) {
+		if (!(chan->generatordata = gen->alloc(chan, params)))
+			res = -1;
+	}
+	
+	if (!res) {
 		ast_settimeout(chan, 160, generator_force, chan);
 		chan->generator = gen;
-	} else {
-		res = -1;
 	}
+
 	ast_mutex_unlock(&chan->lock);
+
 	return res;
 }
 
@@ -1661,12 +1889,9 @@ struct ast_frame *ast_read(struct ast_channel *chan)
 			ast_frfree(f);
 			f = &null_frame;
 		} else {
-			if (chan->spiers) {
-				struct ast_channel_spy *spying;
-				for (spying = chan->spiers; spying; spying=spying->next) {
-					ast_queue_spy_frame(spying, f, 0);
-				}
-			}
+			if (chan->spies)
+				queue_frame_to_spies(chan, f, SPY_READ);
+
 			if (chan->monitor && chan->monitor->read_stream ) {
 #ifndef MONITOR_CONSTANT_DELAY
 				int jump = chan->outsmpl - chan->insmpl - 2 * f->samples;
@@ -2007,17 +2232,10 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
 		break;
 	default:
 		if (chan->tech->write) {
-			if (chan->writetrans) 
-				f = ast_translate(chan->writetrans, fr, 0);
-			else
-				f = fr;
+			f = (chan->writetrans) ? ast_translate(chan->writetrans, fr, 0) : fr;
 			if (f) {
-				if (f->frametype == AST_FRAME_VOICE && chan->spiers) {
-					struct ast_channel_spy *spying;
-					for (spying = chan->spiers; spying; spying=spying->next) {
-						ast_queue_spy_frame(spying, f, 1);
-					}
-				}
+				if (f->frametype == AST_FRAME_VOICE && chan->spies)
+					queue_frame_to_spies(chan, f, SPY_WRITE);
 
 				if( chan->monitor && chan->monitor->write_stream &&
 						f && ( f->frametype == AST_FRAME_VOICE ) ) {
@@ -3207,8 +3425,9 @@ enum ast_bridge_result ast_channel_bridge(struct ast_channel *c0, struct ast_cha
 		if (c0->tech->bridge &&
 		    (config->timelimit == 0) &&
 		    (c0->tech->bridge == c1->tech->bridge) &&
-		    !nativefailed && !c0->monitor && !c1->monitor && !c0->spiers && !c1->spiers) {
-			/* Looks like they share a bridge method */
+		    !nativefailed && !c0->monitor && !c1->monitor &&
+		    !c0->spies && !c1->spies) {
+			/* Looks like they share a bridge method and nothing else is in the way */
 			if (option_verbose > 2) 
 				ast_verbose(VERBOSE_PREFIX_3 "Attempting native bridge of %s and %s\n", c0->name, c1->name);
 			ast_set_flag(c0, AST_FLAG_NBRIDGE);
@@ -3237,6 +3456,7 @@ enum ast_bridge_result ast_channel_bridge(struct ast_channel *c0, struct ast_cha
 			} else {
 				ast_clear_flag(c0, AST_FLAG_NBRIDGE);
 				ast_clear_flag(c1, AST_FLAG_NBRIDGE);
+				ast_verbose(VERBOSE_PREFIX_3 "Native bridge of %s and %s was unsuccessful\n", c0->name, c1->name);
 			}
 			if (res == AST_BRIDGE_RETRY)
 				continue;
@@ -3570,3 +3790,134 @@ void ast_set_variables(struct ast_channel *chan, struct ast_variable *vars)
 	for (cur = vars; cur; cur = cur->next)
 		pbx_builtin_setvar_helper(chan, cur->name, cur->value);	
 }
+
+static void copy_data_from_queue(struct ast_channel_spy_queue *queue, short *buf, unsigned int samples)
+{
+	struct ast_frame *f;
+	int tocopy;
+	int bytestocopy;
+
+	while (samples) {
+		f = queue->head;
+
+		if (!f) {
+			ast_log(LOG_ERROR, "Ran out of frames before buffer filled!\n");
+			break;
+		}
+
+		tocopy = (f->samples > samples) ? samples : f->samples;
+		bytestocopy = ast_codec_get_len(queue->format, samples);
+		memcpy(buf, f->data, bytestocopy);
+		samples -= tocopy;
+		buf += tocopy;
+		f->samples -= tocopy;
+		f->data += bytestocopy;
+		f->datalen -= bytestocopy;
+		f->offset += bytestocopy;
+		queue->samples -= tocopy;
+		if (!f->samples) {
+			queue->head = f->next;
+			ast_frfree(f);
+		}
+	}
+}
+
+struct ast_frame *ast_channel_spy_read_frame(struct ast_channel_spy *spy, unsigned int samples)
+{
+	struct ast_frame *result;
+	/* buffers are allocated to hold SLINEAR, which is the largest format */
+        short read_buf[samples];
+        short write_buf[samples];
+	struct ast_frame *read_frame;
+	struct ast_frame *write_frame;
+	int need_dup;
+	struct ast_frame stack_read_frame = { .frametype = AST_FRAME_VOICE,
+					      .subclass = spy->read_queue.format,
+					      .data = read_buf,
+					      .samples = samples,
+					      .datalen = ast_codec_get_len(spy->read_queue.format, samples),
+	};
+	struct ast_frame stack_write_frame = { .frametype = AST_FRAME_VOICE,
+					       .subclass = spy->write_queue.format,
+					       .data = write_buf,
+					       .samples = samples,
+					       .datalen = ast_codec_get_len(spy->write_queue.format, samples),
+	};
+
+	/* if a flush has been requested, dump everything in whichever queue is larger */
+	if (ast_test_flag(spy, CHANSPY_TRIGGER_FLUSH)) {
+		if (spy->read_queue.samples > spy->write_queue.samples) {
+			if (ast_test_flag(spy, CHANSPY_READ_VOLADJUST)) {
+				for (result = spy->read_queue.head; result; result = result->next)
+					ast_frame_adjust_volume(result, spy->read_vol_adjustment);
+			}
+			result = spy->read_queue.head;
+			spy->read_queue.head = NULL;
+			spy->read_queue.samples = 0;
+			ast_clear_flag(spy, CHANSPY_TRIGGER_FLUSH);
+			return result;
+		} else {
+			if (ast_test_flag(spy, CHANSPY_WRITE_VOLADJUST)) {
+				for (result = spy->write_queue.head; result; result = result->next)
+					ast_frame_adjust_volume(result, spy->write_vol_adjustment);
+			}
+			result = spy->write_queue.head;
+			spy->write_queue.head = NULL;
+			spy->write_queue.samples = 0;
+			ast_clear_flag(spy, CHANSPY_TRIGGER_FLUSH);
+			return result;
+		}
+	}
+
+	if ((spy->read_queue.samples < samples) || (spy->write_queue.samples < samples))
+		return NULL;
+
+	/* short-circuit if both head frames have exactly what we want */
+	if ((spy->read_queue.head->samples == samples) &&
+	    (spy->write_queue.head->samples == samples)) {
+		read_frame = spy->read_queue.head;
+		spy->read_queue.head = read_frame->next;
+		read_frame->next = NULL;
+
+		write_frame = spy->write_queue.head;
+		spy->write_queue.head = write_frame->next;
+		write_frame->next = NULL;
+
+		spy->read_queue.samples -= samples;
+		spy->write_queue.samples -= samples;
+
+		need_dup = 0;
+	} else {
+		copy_data_from_queue(&spy->read_queue, read_buf, samples);
+		copy_data_from_queue(&spy->write_queue, write_buf, samples);
+
+		read_frame = &stack_read_frame;
+		write_frame = &stack_write_frame;
+		need_dup = 1;
+	}
+	
+	if (ast_test_flag(spy, CHANSPY_READ_VOLADJUST))
+		ast_frame_adjust_volume(read_frame, spy->read_vol_adjustment);
+
+	if (ast_test_flag(spy, CHANSPY_WRITE_VOLADJUST))
+		ast_frame_adjust_volume(write_frame, spy->write_vol_adjustment);
+
+	if (ast_test_flag(spy, CHANSPY_MIXAUDIO)) {
+		ast_frame_slinear_sum(read_frame, write_frame);
+
+		if (need_dup)
+			result = ast_frdup(read_frame);
+		else
+			result = read_frame;
+	} else {
+		if (need_dup) {
+			result = ast_frdup(read_frame);
+			result->next = ast_frdup(write_frame);
+		} else {
+			result = read_frame;
+			result->next = write_frame;
+		}
+	}
+
+	return result;
+}
diff --git a/include/asterisk/channel.h b/include/asterisk/channel.h
index 03e8da4fa..8c67b1631 100755
--- a/include/asterisk/channel.h
+++ b/include/asterisk/channel.h
@@ -23,12 +23,6 @@
 #ifndef _ASTERISK_CHANNEL_H
 #define _ASTERISK_CHANNEL_H
 
-#include "asterisk/compat.h"
-#include "asterisk/frame.h"
-#include "asterisk/sched.h"
-#include "asterisk/chanvars.h"
-#include "asterisk/config.h"
-
 #include <unistd.h>
 #include <setjmp.h>
 #ifdef POLLCOMPAT 
@@ -41,18 +35,23 @@
 extern "C" {
 #endif
 
-#include "asterisk/lock.h"
-
 /*! Max length of an extension */
 #define AST_MAX_EXTENSION	80
 
 #define AST_MAX_CONTEXT		80
 
+#define AST_CHANNEL_NAME	80
+
+#include "asterisk/compat.h"
+#include "asterisk/frame.h"
+#include "asterisk/sched.h"
+#include "asterisk/chanvars.h"
+#include "asterisk/config.h"
+#include "asterisk/lock.h"
 #include "asterisk/cdr.h"
 #include "asterisk/monitor.h"
 #include "asterisk/utils.h"
-
-#define AST_CHANNEL_NAME	80
+#include "asterisk/linkedlists.h"
 
 #define MAX_LANGUAGE		20
 
@@ -170,17 +169,48 @@ struct ast_channel_tech {
 };
 
 
-#define CHANSPY_NEW 0
-#define CHANSPY_RUNNING 1
-#define CHANSPY_DONE 2
+enum chanspy_states {
+	CHANSPY_NEW = 0,
+	CHANSPY_RUNNING = 1,
+	CHANSPY_DONE = 2,
+};
+
+enum chanspy_flags {
+	CHANSPY_MIXAUDIO = (1 << 0),
+	CHANSPY_READ_VOLADJUST = (1 << 1),
+	CHANSPY_WRITE_VOLADJUST = (1 << 2),
+	CHANSPY_FORMAT_AUDIO = (1 << 3),
+	CHANSPY_TRIGGER_MODE = (3 << 4),
+	CHANSPY_TRIGGER_READ = (1 << 4),
+	CHANSPY_TRIGGER_WRITE = (2 << 4),
+	CHANSPY_TRIGGER_NONE = (3 << 4),
+	CHANSPY_TRIGGER_FLUSH = (1 << 6),
+};
+
+struct ast_channel_spy_queue {
+	struct ast_frame *head;
+	unsigned int samples;
+	unsigned int format;
+};
 
 struct ast_channel_spy {
-	struct ast_frame *queue[2];
 	ast_mutex_t lock;
-	char status;
-	struct ast_channel_spy *next;
+	ast_cond_t trigger;
+	struct ast_channel_spy_queue read_queue;
+	struct ast_channel_spy_queue write_queue;
+	unsigned int flags;
+	enum chanspy_states status;
+	const char *type;
+	/* The volume adjustment values are very straightforward:
+	   positive values cause the samples to be multiplied by that amount
+	   negative values cause the samples to be divided by the absolute value of that amount
+	*/
+	int read_vol_adjustment;
+	int write_vol_adjustment;
+	AST_LIST_ENTRY(ast_channel_spy) list;
 };
 
+struct ast_channel_spy_list;
 
 /*! Main Channel structure associated with a channel. */
 /*! 
@@ -345,11 +375,10 @@ struct ast_channel {
 	int rawwriteformat;
 
 	/*! Chan Spy stuff */
-	struct ast_channel_spy *spiers;
+	struct ast_channel_spy_list *spies;
 
 	/*! For easy linking */
 	struct ast_channel *next;
-
 };
 
 /* Channel tech properties: */
@@ -1008,6 +1037,50 @@ void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_
 */
 void ast_set_variables(struct ast_channel *chan, struct ast_variable *vars);
 
+/*!
+  \brief Adds a spy to a channel, to begin receiving copies of the channel's audio frames.
+  \param chan The channel to add the spy to.
+  \param spy A pointer to ast_channel_spy structure describing how the spy is to be used.
+  \return 0 for success, non-zero for failure
+ */
+int ast_channel_spy_add(struct ast_channel *chan, struct ast_channel_spy *spy);
+
+/*!
+  \brief Remove a spy from a channel.
+  \param chan The channel to remove the spy from
+  \param spy The spy to be removed
+  \return nothing
+ */
+void ast_channel_spy_remove(struct ast_channel *chan, struct ast_channel_spy *spy);
+
+/*!
+  \brief Find all spies of a particular type on a channel and stop them.
+  \param chan The channel to operate on
+  \param type A character string identifying the type of spies to be stopped
+  \return nothing
+ */
+void ast_channel_spy_stop_by_type(struct ast_channel *chan, const char *type);
+
+/*!
+  \brief Read one (or more) frames of audio from a channel being spied upon.
+  \param spy The spy to operate on
+  \param samples The number of audio samples to read
+  \return NULL for failure, one ast_frame pointer, or a chain of ast_frame pointers
+
+  This function can return multiple frames if the spy structure needs to be 'flushed'
+  due to mismatched queue lengths, or if the spy structure is configured to return
+  unmixed audio (in which case each call to this function will return a frame of audio
+  from each side of channel).
+ */
+struct ast_frame *ast_channel_spy_read_frame(struct ast_channel_spy *spy, unsigned int samples);
+
+/*!
+  \brief Efficiently wait until audio is available for a spy, or an exception occurs.
+  \param spy The spy to wait on
+  \return nothing
+ */
+void ast_channel_spy_trigger_wait(struct ast_channel_spy *spy);
+
 /* Misc. functions below */
 
 /* Helper function for migrating select to poll */