Enable D-Bus delay signals for processing delay

Make sure that clients are informed of significant changes to the
decoder internal processing delay, even when used with remote
devices that do not report their own delay.

doc/a2dpconf.1.rst

@@ -36,7 +36,7 @@ OPTIONS
     Print version and exit.
 
 -v, --verbose
-    Sow verbose bit-stream details.
+    Show verbose bit-stream details.
     Display each field as a binary mask with each bit represented by a single
     character.
 

src/a2dp-aac.c

@@ -30,6 +30,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-dbus.h"
 #include "io.h"
 #include "rtp.h"
 #include "utils.h"
@@ -377,6 +378,7 @@ void *a2dp_aac_enc_thread(struct ba_transport_pcm *t_pcm) {
 					if (!io.initiated) {
 						/* Get the delay due to codec processing. */
 						t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+						ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 						io.initiated = true;
 					}
 

src/a2dp-aptx-hd.c

@@ -26,6 +26,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-dbus.h"
 #include "codec-aptx.h"
 #include "io.h"
 #include "rtp.h"
@@ -208,6 +209,7 @@ void *a2dp_aptx_hd_enc_thread(struct ba_transport_pcm *t_pcm) {
 			if (!io.initiated) {
 				/* Get the delay due to codec processing. */
 				t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+				ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 				io.initiated = true;
 			}
 

src/a2dp-aptx.c

@@ -25,6 +25,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-dbus.h"
 #include "codec-aptx.h"
 #include "io.h"
 #include "shared/a2dp-codecs.h"
@@ -192,6 +193,7 @@ void *a2dp_aptx_enc_thread(struct ba_transport_pcm *t_pcm) {
 			if (!io.initiated) {
 				/* Get the delay due to codec processing. */
 				t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+				ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 				io.initiated = true;
 			}
 

src/a2dp-faststream.c

@@ -24,6 +24,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-dbus.h"
 #include "codec-sbc.h"
 #include "io.h"
 #include "shared/a2dp-codecs.h"
@@ -216,6 +217,7 @@ void *a2dp_fs_enc_thread(struct ba_transport_pcm *t_pcm) {
 			if (!io.initiated) {
 				/* Get the delay due to codec processing. */
 				t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+				ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 				io.initiated = true;
 			}
 

src/a2dp-lc3plus.c

@@ -30,6 +30,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-dbus.h"
 #include "io.h"
 #include "rtp.h"
 #include "utils.h"
@@ -356,6 +357,7 @@ void *a2dp_lc3plus_enc_thread(struct ba_transport_pcm *t_pcm) {
 				if (!io.initiated) {
 					/* Get the delay due to codec processing. */
 					t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+					ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 					io.initiated = true;
 				}
 

src/a2dp-ldac.c

@@ -27,6 +27,7 @@
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
 #include "ba-config.h"
+#include "bluealsa-dbus.h"
 #include "io.h"
 #include "rtp.h"
 #include "utils.h"
@@ -247,6 +248,7 @@ void *a2dp_ldac_enc_thread(struct ba_transport_pcm *t_pcm) {
 				if (!io.initiated) {
 					/* Get the delay due to codec processing. */
 					t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+					ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 					io.initiated = true;
 				}
 

src/a2dp-lhdc.c

@@ -29,6 +29,7 @@
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
 #include "ba-config.h"
+#include "bluealsa-dbus.h"
 #include "io.h"
 #include "rtp.h"
 #include "utils.h"
@@ -278,6 +279,7 @@ void *a2dp_lhdc_enc_thread(struct ba_transport_pcm *t_pcm) {
 				if (!io.initiated) {
 					/* Get the delay due to codec processing. */
 					t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+					ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 					io.initiated = true;
 				}
 

src/a2dp-mpeg.c

@@ -35,6 +35,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-dbus.h"
 #include "io.h"
 #include "rtp.h"
 #include "utils.h"
@@ -297,6 +298,7 @@ void *a2dp_mp3_enc_thread(struct ba_transport_pcm *t_pcm) {
 				if (!io.initiated) {
 					/* Get the delay due to codec processing. */
 					t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+					ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 					io.initiated = true;
 				}
 

src/a2dp-opus.c

@@ -28,6 +28,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-dbus.h"
 #include "io.h"
 #include "rtp.h"
 #include "shared/a2dp-codecs.h"
@@ -233,6 +234,7 @@ void *a2dp_opus_enc_thread(struct ba_transport_pcm *t_pcm) {
 			if (!io.initiated) {
 				/* Get the delay due to codec processing. */
 				t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+				ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 				io.initiated = true;
 			}
 

src/a2dp-sbc.c

@@ -29,6 +29,7 @@
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
 #include "ba-config.h"
+#include "bluealsa-dbus.h"
 #include "codec-sbc.h"
 #include "io.h"
 #include "rtp.h"
@@ -267,6 +268,7 @@ void *a2dp_sbc_enc_thread(struct ba_transport_pcm *t_pcm) {
 				 * frame is written, the BT sink can start decoding and playing
 				 * audio in a continuous fashion. */
 				t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+				ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 				io.initiated = true;
 			}
 

src/ba-transport-pcm.c

@@ -750,39 +750,58 @@ int ba_transport_pcm_delay_get(const struct ba_transport_pcm *pcm) {
 int ba_transport_pcm_delay_sync(struct ba_transport_pcm *pcm, unsigned int update_mask) {
 
 	struct ba_transport *t = pcm->t;
-	int delay = 0;
-
-	delay += pcm->codec_delay_dms;
-	delay += pcm->processing_delay_dms;
-	delay += pcm->client_delay_dms;
 
 	/* In case of A2DP Sink, update the delay property of the BlueZ media
 	 * transport interface. BlueZ should forward this value to the remote
 	 * device, so it can adjust audio/video synchronization. */
-	if (t->profile == BA_TRANSPORT_PROFILE_A2DP_SINK &&
-			t->a2dp.delay_reporting &&
-			abs(delay - t->a2dp.delay) >= 100 /* 10ms */) {
-
-		GError *err = NULL;
-		t->a2dp.delay = delay;
-		g_dbus_set_property(config.dbus, t->bluez_dbus_owner, t->bluez_dbus_path,
-				BLUEZ_IFACE_MEDIA_TRANSPORT, "Delay", g_variant_new_uint16(delay), &err);
-
-		if (err != NULL) {
-			if (err->code == G_DBUS_ERROR_PROPERTY_READ_ONLY)
-				/* Even though BlueZ documentation says that the Delay property is
-				 * read-write, it might not be true. In case when the delay write
-				 * operation fails with "not writable" error, we should not try to
-				 * update the delay report value any more. */
-				t->a2dp.delay_reporting = false;
-			warn("Couldn't set A2DP transport delay: %s", err->message);
-			g_error_free(err);
+	if (t->profile == BA_TRANSPORT_PROFILE_A2DP_SINK) {
+
+		int delay = 0;
+		delay += pcm->codec_delay_dms;
+		delay += pcm->processing_delay_dms;
+		delay += pcm->client_delay_dms;
+
+		if (t->a2dp.delay_reporting &&
+					abs(delay - t->a2dp.delay) >= 100 /* 10ms */) {
+
+			GError *err = NULL;
+			t->a2dp.delay = delay;
+			g_dbus_set_property(config.dbus, t->bluez_dbus_owner, t->bluez_dbus_path,
+					BLUEZ_IFACE_MEDIA_TRANSPORT, "Delay", g_variant_new_uint16(delay), &err);
+
+			if (err != NULL) {
+				if (err->code == G_DBUS_ERROR_PROPERTY_READ_ONLY)
+					/* Even though BlueZ documentation says that the Delay
+					 * property is read-write, it might not be true. In case
+					 * when the delay write operation fails with "not writable"
+					 * error, we should not try to update the delay report
+					 * value any more. */
+					t->a2dp.delay_reporting = false;
+				warn("Couldn't set A2DP transport delay: %s", err->message);
+				g_error_free(err);
+			}
+
 		}
+	}
 
+	/* If the remote device does not provide delay update reports we can still
+	 * inform local D-Bus clients of our internal processing delay. */
+	if ((t->profile & BA_TRANSPORT_PROFILE_MASK_A2DP) == 0 ||
+				!t->a2dp.delay_reporting) {
+		if (update_mask == BA_DBUS_PCM_UPDATE_DELAY) {
+			/* To avoid creating a flood of D-Bus signals, we only notify clients
+			 * when the codec + processing value changes by more than 10ms. */
+			int delay = pcm->codec_delay_dms + pcm->processing_delay_dms;
+			if (abs(delay - (int)pcm->reported_codec_delay_dms) < 100 /* 10ms */)
+				goto final;
+			pcm->reported_codec_delay_dms = delay;
+		}
 	}
 
 	/* Notify all connected D-Bus clients. */
 	bluealsa_dbus_pcm_update(pcm, update_mask);
+
+final:
 	return 0;
 }
 

src/ba-transport-pcm.h

@@ -129,6 +129,9 @@ struct ba_transport_pcm {
 	 * the host computational power. It is used to compensate for the time
 	 * required to encode or decode audio. */
 	unsigned int processing_delay_dms;
+	/* The last reported total codec + processing delay. It is used to limit
+	 * the rate at which changes are reported via D-Bus. */
+	unsigned int reported_codec_delay_dms;
 	/* Positive (or negative) delay reported by the client. */
 	int client_delay_dms;
 

src/bluealsa-dbus.c

@@ -538,6 +538,11 @@ static void bluealsa_pcm_open(GDBusMethodInvocation *inv, void *userdata) {
 			goto fail;
 		}
 
+		/* If the transport thread has updated its codec delay value during its
+		 * start procedure then we inform clients that the delay has changed. */
+		if (pcm->codec_delay_dms > 0)
+			bluealsa_dbus_pcm_update(pcm, BA_DBUS_PCM_UPDATE_DELAY);
+
 	}
 
 	pthread_mutex_lock(&pcm->mutex);

src/sco-lc3-swb.c

@@ -22,6 +22,7 @@
 
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-dbus.h"
 #include "codec-lc3-swb.h"
 #include "io.h"
 #include "shared/defs.h"
@@ -80,6 +81,7 @@ void *sco_lc3_swb_enc_thread(struct ba_transport_pcm *t_pcm) {
 				if (!io.initiated) {
 					/* Get the delay due to codec processing. */
 					t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+					ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 					io.initiated = true;
 				}
 

src/sco-msbc.c

@@ -19,6 +19,7 @@
 
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-dbus.h"
 #include "codec-msbc.h"
 #include "io.h"
 #include "shared/defs.h"
@@ -87,6 +88,7 @@ void *sco_msbc_enc_thread(struct ba_transport_pcm *t_pcm) {
 				if (!io.initiated) {
 					/* Get the delay due to codec processing. */
 					t_pcm->processing_delay_dms = asrsync_get_dms_since_last_sync(&io.asrs);
+					ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 					io.initiated = true;
 				}
 

test/test-a2dp.c

@@ -51,6 +51,8 @@ int ba_transport_pcm_state_set(struct ba_transport_pcm *pcm,
 enum ba_transport_pcm_signal ba_transport_pcm_signal_recv(struct ba_transport_pcm *pcm) {
 	(void)pcm; return -1; }
 void ba_transport_pcm_thread_cleanup(struct ba_transport_pcm *pcm) { (void)pcm; }
+int ba_transport_pcm_delay_sync(struct ba_transport_pcm *pcm, unsigned int update_mask) {
+	(void)pcm; (void)update_mask; return -1; }
 
 CK_START_TEST(test_a2dp_codecs_codec_id_from_string) {
 	ck_assert_uint_eq(a2dp_codecs_codec_id_from_string("SBC"), A2DP_CODEC_SBC);