optionally send silence during recording (issue #5135)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6925 65c4cc65-6c06-0410-ace0-fbb531ad65f3

app.c

@@ -560,6 +560,7 @@ int ast_play_and_record(struct ast_channel *chan, const char *playfile, const ch
 	int dspsilence = 0;
 	int gotsilence = 0;		/* did we timeout for silence? */
 	int rfmt=0;
+	struct ast_silence_generator *silgen = NULL;
 
 	if (silencethreshold < 0)
 		silencethreshold = global_silence_threshold;
@@ -615,8 +616,6 @@ int ast_play_and_record(struct ast_channel *chan, const char *playfile, const ch
 	if (path)
 		ast_unlock_path(path);
 
-
-	
 	if (maxsilence > 0) {
 		sildet = ast_dsp_new(); /* Create the silence detector */
 		if (!sildet) {
@@ -632,9 +631,13 @@ int ast_play_and_record(struct ast_channel *chan, const char *playfile, const ch
 			return -1;
 		}
 	}
+
 	/* Request a video update */
 	ast_indicate(chan, AST_CONTROL_VIDUPDATE);
 
+	if (option_transmit_silence_during_record)
+		silgen = ast_channel_start_silence_generator(chan);
+
 	if (x == fmtcnt) {
 	/* Loop forever, writing the packets we read to the writer(s), until
 	   we read a # or get a hangup */
@@ -735,6 +738,9 @@ int ast_play_and_record(struct ast_channel *chan, const char *playfile, const ch
 		ast_log(LOG_WARNING, "Error creating writestream '%s', format '%s'\n", recordfile, sfmt[x]);
 	}
 
+	if (silgen)
+		ast_channel_stop_silence_generator(chan, silgen);
+
 	*duration = end - start;
 
 	for (x=0;x<fmtcnt;x++) {

apps/app_record.c

@@ -38,6 +38,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/translate.h"
 #include "asterisk/dsp.h"
 #include "asterisk/utils.h"
+#include "asterisk/options.h"
 
 static char *tdesc = "Trivial Record Application";
 
@@ -98,6 +99,8 @@ static int record_exec(struct ast_channel *chan, void *data)
 	int option_quiet = 0;
 	int rfmt = 0;
 	int flags;
+	int waitres;
+	struct ast_silence_generator *silgen = NULL;
 	
 	/* The next few lines of code parse out the filename and header from the input string */
 	if (ast_strlen_zero(data)) { /* no data implies no filename or anything is present */
@@ -199,7 +202,10 @@ static int record_exec(struct ast_channel *chan, void *data)
 		}
 	}
 	
-	if (!res) {
+	if (res) {
+		ast_log(LOG_WARNING, "Could not answer channel '%s'\n", chan->name);
+		goto out;
+	}
 	
 	if (!option_quiet) {
 		/* Some code to play a nice little beep to signify the start of the record operation */
@@ -235,8 +241,13 @@ static int record_exec(struct ast_channel *chan, void *data)
 	flags = option_append ? O_CREAT|O_APPEND|O_WRONLY : O_CREAT|O_TRUNC|O_WRONLY;
 	s = ast_writefile( tmp, ext, NULL, flags , 0, 0644);
 		
-		if (s) {
-			int waitres;
+	if (!s) {
+		ast_log(LOG_WARNING, "Could not create file %s\n", filename);
+		goto out;
+	}
+
+	if (option_transmit_silence_during_record)
+		silgen = ast_channel_start_silence_generator(chan);
 	
 	/* Request a video update */
 	ast_indicate(chan, AST_CONTROL_VIDUPDATE);
@@ -311,11 +322,11 @@ static int record_exec(struct ast_channel *chan, void *data)
 		ast_truncstream(s);
 	}
 	ast_closestream(s);
-		} else			
-			ast_log(LOG_WARNING, "Could not create file %s\n", filename);
-	} else
-		ast_log(LOG_WARNING, "Could not answer channel '%s'\n", chan->name);
 
+	if (silgen)
+		ast_channel_stop_silence_generator(chan, silgen);
+	
+ out:
 	if ((silence > 0) && rfmt) {
 		res = ast_set_read_format(chan, rfmt);
 		if (res)

asterisk.c

@@ -142,6 +142,7 @@ int option_timestamp = 0;
 int option_overrideconfig = 0;
 int option_reconnect = 0;
 int option_transcode_slin = 1;
+int option_transmit_silence_during_record = 0;
 int option_maxcalls = 0;
 double option_maxload = 0.0;
 int option_dontwarn = 0;
@@ -1869,6 +1870,9 @@ static void ast_readconfig(void) {
 		/* Build transcode paths via SLINEAR, instead of directly */
 		} else if (!strcasecmp(v->name, "transcode_via_sln")) {
 			option_transcode_slin = ast_true(v->value);
+		/* Transmit SLINEAR silence while a channel is being recorded */
+		} else if (!strcasecmp(v->name, "transmit_silence_during_record")) {
+			option_transmit_silence_during_record = ast_true(v->value);
 		} else if (!strcasecmp(v->name, "maxcalls")) {
 			if ((sscanf(v->value, "%d", &option_maxcalls) != 1) || (option_maxcalls < 0)) {
 				option_maxcalls = 0;

channel.c

@@ -3921,3 +3921,100 @@ struct ast_frame *ast_channel_spy_read_frame(struct ast_channel_spy *spy, unsign
 
 	return result;
 }
+
+static void *silence_generator_alloc(struct ast_channel *chan, void *data)
+{
+	/* just store the data pointer in the channel structure */
+	return data;
+}
+
+static void silence_generator_release(struct ast_channel *chan, void *data)
+{
+	/* nothing to do */
+}
+
+static short normal_silence_buf[160] = { 0, };
+static struct ast_frame normal_silence_frame = {
+	.frametype = AST_FRAME_VOICE,
+	.subclass = AST_FORMAT_SLINEAR,
+	.data = normal_silence_buf,
+	.samples = 160,
+	.datalen = sizeof(normal_silence_buf),
+};
+
+static int silence_generator_generate(struct ast_channel *chan, void *data, int len, int samples) 
+{
+	if (samples == 160) {
+		if (ast_write(chan, &normal_silence_frame))
+			return -1;
+	} else {
+		short buf[samples];
+		int x;
+		struct ast_frame frame = {
+			.frametype = AST_FRAME_VOICE,
+			.subclass = AST_FORMAT_SLINEAR,
+			.data = normal_silence_buf,
+			.samples = samples,
+			.datalen = sizeof(buf),
+		};
+
+		for (x = 0; x < samples; x++)
+			buf[x] = 0;
+
+		if (ast_write(chan, &frame))
+			return -1;
+	}
+
+	return 0;
+}
+
+static struct ast_generator silence_generator = {
+	.alloc = silence_generator_alloc,
+	.release = silence_generator_release,
+	.generate = silence_generator_generate, 
+};
+
+struct ast_silence_generator {
+	int old_write_format;
+};
+
+struct ast_silence_generator *ast_channel_start_silence_generator(struct ast_channel *chan)
+{
+	struct ast_silence_generator *state;
+
+	if (!(state = calloc(1, sizeof(*state)))) {
+		ast_log(LOG_WARNING, "Could not allocate state structure\n");
+		return NULL;
+	}
+
+	state->old_write_format = chan->writeformat;
+
+	if (ast_set_write_format(chan, AST_FORMAT_SLINEAR) < 0) {
+		ast_log(LOG_ERROR, "Could not set write format to SLINEAR\n");
+		free(state);
+		return NULL;
+	}
+
+	ast_activate_generator(chan, &silence_generator, state);
+
+	if (option_debug)
+		ast_log(LOG_DEBUG, "Started silence generator on '%s'\n", chan->name);
+
+	return state;
+}
+
+void ast_channel_stop_silence_generator(struct ast_channel *chan, struct ast_silence_generator *state)
+{
+	if (!state)
+		return;
+
+	ast_deactivate_generator(chan);
+
+	if (option_debug)
+		ast_log(LOG_DEBUG, "Stopped silence generator on '%s'\n", chan->name);
+
+	if (ast_set_write_format(chan, state->old_write_format) < 0)
+		ast_log(LOG_ERROR, "Could not return write format to its original state\n");
+
+	free(state);
+}

doc/README.asterisk.conf

@@ -39,8 +39,8 @@ astlogdir => /var/log/asterisk
 ;Under "options" you can enter configuration options
 ;that you also can set with command line options
 
-verbose=0		; Verbosity level for logging (-v)
-debug=3			; Debug: "No" or value (1-4)
+verbose = 0					; Verbosity level for logging (-v)
+debug = 3					; Debug: "No" or value (1-4)
 nofork=yes | no					; Background execution disabled (-f)
 console= yes | no				; Console mode (-c)
 highpriority = yes | no				; Execute with high priority (-p)
@@ -49,14 +49,16 @@ nocolor = yes | no	; Disable ANSI colors (-n)
 dumpcore = yes | no				; Dump core on failure (-g)
 quiet = yes | no				; Run quietly (-q)
 timestamp = yes | no				; Force timestamping on log entries to console (-T)
-execincludes = yes | no ; Allow #exec entries in configuration files
-dontwarn = yes | no	; Don't over-inform the Asterisk sysadm, he's a guru
+
+;These options have no command line equivalent
+cache_record_files = yes | no			; Cache record() files in another directory until completion
+record_cache_dir = <dir>
 transcode_via_sln = yes | no 			; Build transcode paths via SLINEAR
-maxcalls = 255		; The maximum number of concurrent calls you want to allow 
+transmit_silence_during_record = yes | no	; send SLINEAR silence while channel is being recorded
 maxload = 1.0					; The maximum load average we accept calls for
-		
-;This option has no command line equivalent
-cache_record_files = yes | no	; Cache record() files in another directory until 				completion record_cache_dir = <dir>
+maxcalls = 255					; The maximum number of concurrent calls you want to allow 
+execincludes = yes | no 			; Allow #exec entries in configuration files
+dontwarn = yes | no				; Don't over-inform the Asterisk sysadm, he's a guru
 
 [files]
 ; Changing the following lines may compromise your security

include/asterisk/channel.h

@@ -1099,6 +1099,10 @@ struct ast_frame *ast_channel_spy_read_frame(struct ast_channel_spy *spy, unsign
  */
 void ast_channel_spy_trigger_wait(struct ast_channel_spy *spy);
 
+struct ast_silence_generator;
+struct ast_silence_generator *ast_channel_start_silence_generator(struct ast_channel *chan);
+void ast_channel_stop_silence_generator(struct ast_channel *chan, struct ast_silence_generator *state);
+
 /* Misc. functions below */
 
 /* Helper function for migrating select to poll */

include/asterisk/options.h

@@ -42,6 +42,7 @@ extern int option_exec_includes;
 extern int option_cache_record_files;
 extern int option_timestamp;
 extern int option_transcode_slin;
+extern int option_transmit_silence_during_record;
 extern int option_maxcalls;
 extern double option_maxload;
 extern int option_dontwarn;