TT#101653 add silence detection option

Change-Id: I14940fcabdef475ed5dbe74d9af7ebc2af10311b

README.md

@@ -54,6 +54,7 @@ the following additional features are available:
 - Injection of DTMF events or PCM DTMF tones into running audio streams
 - Playback of pre-recorded streams/announcements
 - Transcoding between T.38 and PCM (G.711 or other audio codecs)
+- Silence detection and comfort noise (RFC 3389) payloads
 
 *Rtpengine* does not (yet) support:
 

daemon/codec.c

@@ -85,6 +85,11 @@ struct dtx_entry {
 	void *ssrc_ptr; // opaque pointer, doesn't hold a reference
 };
 
+struct silence_event {
+	uint64_t start;
+	uint64_t end;
+};
+
 struct codec_ssrc_handler {
 	struct ssrc_entry h; // must be first
 	struct codec_handler *handler;
@@ -109,6 +114,9 @@ struct codec_ssrc_handler {
 	GQueue dtmf_events;
 	struct dtmf_event dtmf_event;
 
+	// silence detection
+	GQueue silence_events;
+
 	uint64_t skip_pts;
 
 	int rtp_mark:1;
@@ -1169,6 +1177,7 @@ void codec_handlers_update(struct call_media *receiver, struct call_media *sink,
 	struct rtp_payload_type *dtmf_pt = NULL;
 	struct rtp_payload_type *reverse_dtmf_pt = NULL;
 	int dtmf_pt_match = __supp_codec_match(receiver, sink, dtmf_payload_type, &dtmf_pt, &reverse_dtmf_pt);
+	int cn_pt_match = __supp_codec_match(receiver, sink, cn_payload_type, NULL, NULL);
 
 	// stop transcoding if we've determined that we don't need it
 	if (MEDIA_ISSET(sink, TRANSCODE) && !sink_transcoding) {
@@ -1240,8 +1249,8 @@ void codec_handlers_update(struct call_media *receiver, struct call_media *sink,
 
 		GQueue *dest_codecs = NULL;
 		if (!flags || !flags->always_transcode) {
-			// we ignore output codec matches if we must transcode DTMF
-			if (dtmf_pt_match == 1 && MEDIA_ISSET(sink, TRANSCODE))
+			// we ignore output codec matches if we must transcode supp codecs
+			if ((dtmf_pt_match == 1 || cn_pt_match == 1) && MEDIA_ISSET(sink, TRANSCODE))
 				;
 			else if (pcm_dtmf_detect)
 				;
@@ -1293,6 +1302,11 @@ void codec_handlers_update(struct call_media *receiver, struct call_media *sink,
 			if (rtp_payload_type_cmp_nf(pt, dest_pt))
 				goto transcode;
 
+			// do we need silence detection?
+			if (cn_pt_match == 2 && MEDIA_ISSET(sink, TRANSCODE))
+				goto transcode;
+
+			// XXX check format parameters as well
 			ilog(LOG_DEBUG, "Sink supports codec " STR_FORMAT, STR_FMT(&pt->encoding_with_params));
 			__make_passthrough_gsl(handler, &passthrough_handlers);
 			if (pt->codec_def && pt->codec_def->dtmf)
@@ -2198,6 +2212,102 @@ void codec_handlers_stop(GQueue *q) {
 }
 
 
+
+
+static void silence_event_free(void *p) {
+	g_slice_free1(sizeof(struct silence_event), p);
+}
+
+#define __silence_detect_type(type) \
+static void __silence_detect_ ## type(struct codec_ssrc_handler *ch, AVFrame *frame, type thres) { \
+	type *s = (void *) frame->data[0]; \
+	struct silence_event *last = g_queue_peek_tail(&ch->silence_events); \
+ \
+	if (last && last->end) /* last event finished? */ \
+		last = NULL; \
+ \
+	for (unsigned int i = 0; i < frame->nb_samples; i++) { \
+		if (s[i] <= thres && s[1] >= -thres) { \
+			/* silence */ \
+			if (!last) { \
+				/* new event */ \
+				last = g_slice_alloc0(sizeof(*last)); \
+				last->start = frame->pts + i; \
+				g_queue_push_tail(&ch->silence_events, last); \
+			} \
+		} \
+		else { \
+			/* not silence */ \
+			if (last && !last->end) { \
+				/* close off event */ \
+				last->end = frame->pts + i; \
+				last = NULL; \
+			} \
+		} \
+	} \
+}
+
+__silence_detect_type(double)
+__silence_detect_type(float)
+__silence_detect_type(int32_t)
+__silence_detect_type(int16_t)
+
+static void __silence_detect(struct codec_ssrc_handler *ch, AVFrame *frame) {
+	if (!rtpe_config.silence_detect_int)
+		return;
+	if (ch->handler->cn_payload_type < 0)
+		return;
+	switch (frame->format) {
+		case AV_SAMPLE_FMT_DBL:
+			__silence_detect_double(ch, frame, rtpe_config.silence_detect_double);
+			break;
+		case AV_SAMPLE_FMT_FLT:
+			__silence_detect_float(ch, frame, rtpe_config.silence_detect_double);
+			break;
+		case AV_SAMPLE_FMT_S32:
+			__silence_detect_int32_t(ch, frame, rtpe_config.silence_detect_int);
+			break;
+		case AV_SAMPLE_FMT_S16:
+			__silence_detect_int16_t(ch, frame, rtpe_config.silence_detect_int >> 16);
+			break;
+		default:
+			ilog(LOG_WARN | LOG_FLAG_LIMIT, "Unsupported sample format %i for silence detection",
+					frame->format);
+	}
+}
+static int is_silence_event(str *inout, GQueue *events, uint64_t pts, uint64_t duration) {
+	uint64_t end = pts + duration;
+
+	while (events->length) {
+		struct silence_event *first = g_queue_peek_head(events);
+		if (first->start > pts) // future event
+			return 0;
+		if (!first->end) // ongoing event
+			goto silence;
+		if (first->end > end) // event finished with end in the future
+			goto silence;
+		// event has ended: remove it
+		g_queue_pop_head(events);
+		// does the event fill the entire span?
+		if (first->end == end) {
+			silence_event_free(first);
+			goto silence;
+		}
+		// keep going, there might be more
+		silence_event_free(first);
+	}
+	return 0;
+
+silence:
+	// replace with CN payload
+	inout->len = rtpe_config.cn_payload.len;
+	memcpy(inout->s, rtpe_config.cn_payload.s, inout->len);
+	return 1;
+}
+
+
+
+
 static struct ssrc_entry *__ssrc_handler_transcode_new(void *p) {
 	struct codec_handler *h = p;
 
@@ -2296,6 +2406,7 @@ static void __free_ssrc_handler(void *chp) {
 		dtmf_rx_free(ch->dtmf_dsp);
 	resample_shutdown(&ch->dtmf_resampler);
 	g_queue_clear_full(&ch->dtmf_events, dtmf_event_free);
+	g_queue_clear_full(&ch->silence_events, silence_event_free);
 	if (ch->dtx_buffer)
 		obj_put(&ch->dtx_buffer->ttq.tt_obj);
 }
@@ -2340,6 +2451,7 @@ static int packet_encoded_rtp(encoder_t *enc, void *u1, void *u2) {
 
 		unsigned int repeats = 0;
 		int payload_type = -1;
+
 		int is_dtmf = dtmf_event_payload(&inout, (uint64_t *) &enc->avpkt.pts, enc->avpkt.duration,
 				&ch->dtmf_event, &ch->dtmf_events);
 		if (is_dtmf) {
@@ -2349,6 +2461,10 @@ static int packet_encoded_rtp(encoder_t *enc, void *u1, void *u2) {
 			else if (is_dtmf == 3)
 				repeats = 2; // DTMF end event
 		}
+		else {
+			if (is_silence_event(&inout, &ch->silence_events, enc->avpkt.pts, enc->avpkt.duration))
+				payload_type = ch->handler->cn_payload_type;
+		}
 
 		// ready to send
 
@@ -2469,6 +2585,7 @@ static int packet_decoded_common(decoder_t *decoder, AVFrame *frame, void *u1, v
 	}
 
 	__dtmf_detect(ch, frame);
+	__silence_detect(ch, frame);
 
 	// locking deliberately ignored
 	if (mp->media_out)

daemon/main.c

@@ -380,6 +380,8 @@ static void options(int *argc, char ***argv) {
 	AUTO_CLEANUP_GBUF(dtmf_udp_ep);
 	AUTO_CLEANUP_GBUF(endpoint_learning);
 	AUTO_CLEANUP_GBUF(dtls_sig);
+	double silence_detect = 0;
+	AUTO_CLEANUP_GVBUF(cn_payload);
 
 	GOptionEntry e[] = {
 		{ "table",	't', 0, G_OPTION_ARG_INT,	&rtpe_config.kernel_table,		"Kernel table to use",		"INT"		},
@@ -465,6 +467,8 @@ static void options(int *argc, char ***argv) {
 #ifdef WITH_TRANSCODING
 		{ "dtx-delay",	0,0,	G_OPTION_ARG_INT,	&rtpe_config.dtx_delay,	"Delay in milliseconds to trigger DTX handling","INT"},
 		{ "max-dtx",	0,0,	G_OPTION_ARG_INT,	&rtpe_config.max_dtx,	"Maximum duration of DTX handling",	"INT"},
+		{ "silence-detect",0,0,	G_OPTION_ARG_DOUBLE,	&silence_detect,	"Audio level threshold in percent for silence detection","FLOAT"},
+		{ "cn-payload",0,0,	G_OPTION_ARG_STRING_ARRAY,&cn_payload,		"Comfort noise parameters to replace silence with","INT INT INT ..."},
 #endif
 
 		{ NULL, }
@@ -684,6 +688,32 @@ static void options(int *argc, char ***argv) {
 
 	if (rtpe_config.jb_length < 0)
 		die("Invalid negative jitter buffer size");
+
+	if (silence_detect > 0) {
+		rtpe_config.silence_detect_double = silence_detect / 100.0;
+		rtpe_config.silence_detect_int = (int) ((silence_detect / 100.0) * UINT32_MAX);
+	}
+
+	if (!cn_payload)
+		str_init_dup(&rtpe_config.cn_payload, "\x20");
+	else {
+		int len = g_strv_length(cn_payload);
+		if (len < 1)
+			die("Invalid CN payload specified");
+		rtpe_config.cn_payload.s = malloc(len);
+		for (int i = 0; i < len; i++) {
+			char *endp;
+			long p = strtol(cn_payload[i], &endp, 0);
+			if (endp == cn_payload[i] || *endp != '\0')
+				die("Invalid CN payload specified");
+			if (p < 0 || p > 254)
+				die("Invalid CN payload specified");
+			if (i == 0 && p > 127)
+				die("Invalid CN payload specified");
+			rtpe_config.cn_payload.s[i] = p;
+		}
+		rtpe_config.cn_payload.len = len;
+	}
 }
 
 void fill_initial_rtpe_cfg(struct rtpengine_config* ini_rtpe_cfg) {

daemon/rtpengine.pod

@@ -745,6 +745,51 @@ received within this time frame, then DTX processing will stop. Can be set to
 zero or negative to disable and keep DTX processing on indefinitely. Defaults
 to 30 seconds.
 
+=item B<--silence-detect=>I<FLOAT>
+
+Enable silence detection and specify threshold in percent. This option is
+applicable to transcoded stream only and defaults to zero (disabled).
+
+When enabled, silence detection will be performed on all transcoded audio
+streams. The threshold specified here is the sensitivity for detecting silence:
+higher thresholds result in more audio to be detected as silence, while lower
+thresholds result in less audio to be detected as silence. The threshold is
+specified as percent between zero and 100. If set to 100, then all audio would
+be detected as silence; if set to 50, then any audio that is quieter than 50%
+of the maximum volume would be detected as silence; and so on. Setting it to
+zero disables silence detection. To only detect silence that is very near or
+equal to absolute silence, set this value to a low number such as 0.01. (For
+certain codecs such as PCMA, a higher minimum threshold is required to detect
+complete silence, as their compressed payloads don't decode to actual silence
+but instead have a residual DC offset. For PCMA the minimum value is 0.013.)
+
+Audio that is detected as silence will be replaced by comfort noise as
+specified by the B<cn-payload> option (see below). Currently this is applicable
+only to RTP peers that have advertised support for the B<CN> RTP payload type,
+in which case the silence audio frames will be replaced by B<CN> RTP frames.
+
+=item B<--cn-payload=>I<INT>
+
+Specify one comfort noise parameter. This option can be given multiple times
+and the format follows RFC 3389. When specified at the command line, list the
+B<--cn-payload=> option multiple times, each one specifying a single CN
+parameter. When used in the config file, list the option only a single time and
+list multiple CN parameters separated by semicolons (e.g.
+I<cn-payload = 20;40;60>).
+
+The first CN payload value given is the noise level, specified as -dBov as per
+RFC 3389. This means that a noise level of zero corresponds to maximum volume,
+while higher numbers correspond to lower volumes. The highest allowable number
+is 127, corresponding to -127 dBov, which is near silence.
+
+Subsequent CN payload values carry spectral information (reflection
+coefficients) as per RFC 3389. Allowable values for each coefficient are
+between 0 and 254. Specifying spectral information is optional and the number
+of coefficients listed (model order) is variable.
+
+The default values are 32 (-32 dBov) for the noise level and no spectral
+information.
+
 =back
 
 =head1 INTERFACES

include/main.h

@@ -108,6 +108,9 @@ struct rtpengine_config {
 	int			http_threads;
 	int			dtx_delay;
 	int			max_dtx;
+	double			silence_detect_double;
+	uint32_t		silence_detect_int;
+	str			cn_payload;
 };
 
 

t/auto-daemon-tests.pl

@@ -10,7 +10,7 @@ use NGCP::Rtpclient::ICE;
 
 
 autotest_start(qw(--config-file=none -t -1 -i 203.0.113.1 -i 2001:db8:4321::1
-			-n 2223 -c 12345 -f -L 7 -E -u 2222))
+			-n 2223 -c 12345 -f -L 7 -E -u 2222 --silence-detect=1))
 		or die;
 
 
@@ -684,7 +684,7 @@ o=- 1545997027 1 IN IP4 198.51.101.1
 s=tester
 t=0 0
 m=audio 3000 RTP/AVP 0
-c=IN IP4 198.51.100.1
+c=IN IP4 198.51.101.1
 a=sendrecv
 ----------------------------------
 v=0
@@ -721,13 +721,82 @@ a=rtcp:PORT
 SDP
 
 snd($sock_a, $port_b, rtp(0, 1000, 3000, 0x1234, "\x00" x 160));
-rcv($sock_b, $port_a, rtpm(0, 1000, 3000, 0x1234, "\x00" x 160));
+rcv($sock_b, $port_a, rtpm(0, 1000, 3000, -1, "\x00" x 160));
+snd($sock_b, $port_a, rtp(0, 2000, 4000, 0x3456, "\x00" x 160));
+($ssrc) = rcv($sock_a, $port_b, rtpm(0, 2000, 4000, -1, "\x00" x 160));
+snd($sock_b, $port_a, rtp(13, 2001, 4160, 0x3456, "\x12\x23\x23\x34\x56"));
+rcv($sock_a, $port_b, rtpm(0, 2001, 4160, $ssrc, "\xce\x56\x69\xcc\x61\xca\x63\xd2\x66\x57\xe2\x47\x65\x59\x6a\x74\x5d\x4a\x68\xe9\x60\x4a\x63\x4b\xf4\x43\x4b\x48\x48\x52\x39\x57\x37\x4c\x39\x4c\x48\x3b\x43\x47\x44\x57\x48\xf5\x3e\x59\x3e\x52\x3b\x53\x3d\x53\x3b\x41\x5b\x38\x4a\x4b\x35\x48\x4a\x3e\x52\x50\x4b\x46\xfd\x3e\xf1\x3a\xd6\x35\x54\x5d\x3a\x58\x45\x42\x3d\x3e\x4c\x42\x3a\x58\x3c\x50\x3b\x6e\x36\x60\x3e\x3d\x3b\x41\x3a\x47\x35\x48\x35\x4b\x3e\x3d\x47\x3a\x3d\x39\x4f\x40\x42\x4a\x47\x3d\x6b\x42\x5a\x75\x53\x45\x5a\x4b\x4f\x48\x59\x48\x78\x43\x77\x4c\x42\x59\x47\x46\x3e\x67\x44\x3a\x67\x4b\x3f\x51\x48\x44\x3e\x54\x37\x6c\x45\x45\x3f\x6e\x3a\x68\x49\x4e\x3f\x47\x4b\x3e\xf3\x39"));
+snd($sock_b, $port_a, rtp(0, 2002, 4320, 0x3456, "\x00" x 160));
+rcv($sock_a, $port_b, rtpm(0, 2002, 4320, $ssrc, "\x00" x 160));
+# test silence detection
+snd($sock_a, $port_b, rtp(0, 1001, 3160, 0x1234, "\x00" x 160));
+($ssrc) = rcv($sock_b, $port_a, rtpm(0, 1001, 3160, -1, "\x00" x 160));
+snd($sock_a, $port_b, rtp(0, 1002, 3320, 0x1234, "\xff" x 160));
+rcv($sock_b, $port_a, rtpm(13, 1002, 3320, $ssrc, "\x20"));
+
+
+
+# reverse of the above, sockets/ports swapped
+
+($sock_b, $sock_a) = new_call([qw(198.51.101.1 6002)], [qw(198.51.101.3 7002)]);
+
+($port_b) = offer('accept CN',
+	{ ICE => 'remove', replace => ['origin'], flags => ['always transcode'] }, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.101.1
+s=tester
+t=0 0
+m=audio 6002 RTP/AVP 0 13
+c=IN IP4 198.51.101.1
+a=sendrecv
+----------------------------------
+v=0
+o=- 1545997027 1 IN IP4 203.0.113.1
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 0 13
+c=IN IP4 203.0.113.1
+a=rtpmap:0 PCMU/8000
+a=rtpmap:13 CN/8000
+a=sendrecv
+a=rtcp:PORT
+SDP
+
+($port_a) = answer('accept CN',
+	{ ICE => 'remove', replace => ['origin'] }, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.101.1
+s=tester
+t=0 0
+m=audio 7002 RTP/AVP 0
+c=IN IP4 198.51.101.3
+a=sendrecv
+----------------------------------
+v=0
+o=- 1545997027 1 IN IP4 203.0.113.1
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 0 13
+c=IN IP4 203.0.113.1
+a=rtpmap:0 PCMU/8000
+a=rtpmap:13 CN/8000
+a=sendrecv
+a=rtcp:PORT
+SDP
+
+snd($sock_a, $port_b, rtp(0, 1000, 3000, 0x1234, "\x00" x 160));
+rcv($sock_b, $port_a, rtpm(0, 1000, 3000, -1, "\x00" x 160));
 snd($sock_b, $port_a, rtp(0, 2000, 4000, 0x3456, "\x00" x 160));
 ($ssrc) = rcv($sock_a, $port_b, rtpm(0, 2000, 4000, -1, "\x00" x 160));
 snd($sock_b, $port_a, rtp(13, 2001, 4160, 0x3456, "\x12\x23\x23\x34\x56"));
 rcv($sock_a, $port_b, rtpm(0, 2001, 4160, $ssrc, "\xce\x56\x69\xcc\x61\xca\x63\xd2\x66\x57\xe2\x47\x65\x59\x6a\x74\x5d\x4a\x68\xe9\x60\x4a\x63\x4b\xf4\x43\x4b\x48\x48\x52\x39\x57\x37\x4c\x39\x4c\x48\x3b\x43\x47\x44\x57\x48\xf5\x3e\x59\x3e\x52\x3b\x53\x3d\x53\x3b\x41\x5b\x38\x4a\x4b\x35\x48\x4a\x3e\x52\x50\x4b\x46\xfd\x3e\xf1\x3a\xd6\x35\x54\x5d\x3a\x58\x45\x42\x3d\x3e\x4c\x42\x3a\x58\x3c\x50\x3b\x6e\x36\x60\x3e\x3d\x3b\x41\x3a\x47\x35\x48\x35\x4b\x3e\x3d\x47\x3a\x3d\x39\x4f\x40\x42\x4a\x47\x3d\x6b\x42\x5a\x75\x53\x45\x5a\x4b\x4f\x48\x59\x48\x78\x43\x77\x4c\x42\x59\x47\x46\x3e\x67\x44\x3a\x67\x4b\x3f\x51\x48\x44\x3e\x54\x37\x6c\x45\x45\x3f\x6e\x3a\x68\x49\x4e\x3f\x47\x4b\x3e\xf3\x39"));
 snd($sock_b, $port_a, rtp(0, 2002, 4320, 0x3456, "\x00" x 160));
 rcv($sock_a, $port_b, rtpm(0, 2002, 4320, $ssrc, "\x00" x 160));
+# test silence detection
+snd($sock_a, $port_b, rtp(0, 1001, 3160, 0x1234, "\x00" x 160));
+($ssrc) = rcv($sock_b, $port_a, rtpm(0, 1001, 3160, -1, "\x00" x 160));
+snd($sock_a, $port_b, rtp(0, 1002, 3320, 0x1234, "\xff" x 160));
+rcv($sock_b, $port_a, rtpm(13, 1002, 3320, $ssrc, "\x20"));