From 3c14b482b6b4b165880154427009f430621bec88 Mon Sep 17 00:00:00 2001
From: borine <32966433+borine@users.noreply.github.com>
Date: Tue, 29 Oct 2024 09:29:00 +0000
Subject: [PATCH] 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     |  2 +-
 src/a2dp-aac.c         |  2 ++
 src/a2dp-aptx-hd.c     |  2 ++
 src/a2dp-aptx.c        |  2 ++
 src/a2dp-faststream.c  |  2 ++
 src/a2dp-lc3plus.c     |  2 ++
 src/a2dp-ldac.c        |  2 ++
 src/a2dp-lhdc.c        |  2 ++
 src/a2dp-mpeg.c        |  2 ++
 src/a2dp-opus.c        |  2 ++
 src/a2dp-sbc.c         |  2 ++
 src/ba-transport-pcm.c | 65 +++++++++++++++++++++++++++---------------
 src/ba-transport-pcm.h |  3 ++
 src/bluealsa-dbus.c    |  5 ++++
 src/sco-cvsd.c         |  2 ++
 src/sco-lc3-swb.c      |  2 ++
 src/sco-msbc.c         |  2 ++
 test/test-a2dp.c       |  2 ++
 18 files changed, 79 insertions(+), 24 deletions(-)

diff --git a/doc/a2dpconf.1.rst b/doc/a2dpconf.1.rst
index 4c7cd6049..53720e564 100644
--- a/doc/a2dpconf.1.rst
+++ b/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.
 
diff --git a/src/a2dp-aac.c b/src/a2dp-aac.c
index 2e8a680d0..94585fef5 100644
--- a/src/a2dp-aac.c
+++ b/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"
@@ -397,6 +398,7 @@ void *a2dp_aac_enc_thread(struct ba_transport_pcm *t_pcm) {
 
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 			/* If the input buffer was not consumed, we have to append new data to
 			 * the existing one. Since we do not use ring buffer, we will simply
diff --git a/src/a2dp-aptx-hd.c b/src/a2dp-aptx-hd.c
index 16664f21d..f6bd9144d 100644
--- a/src/a2dp-aptx-hd.c
+++ b/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"
@@ -213,6 +214,7 @@ void *a2dp_aptx_hd_enc_thread(struct ba_transport_pcm *t_pcm) {
 
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 			/* reinitialize output buffer */
 			ffb_rewind(&bt);
diff --git a/src/a2dp-aptx.c b/src/a2dp-aptx.c
index 171bb3445..67dfd43b5 100644
--- a/src/a2dp-aptx.c
+++ b/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"
@@ -194,6 +195,7 @@ void *a2dp_aptx_enc_thread(struct ba_transport_pcm *t_pcm) {
 
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 			/* reinitialize output buffer */
 			ffb_rewind(&bt);
diff --git a/src/a2dp-faststream.c b/src/a2dp-faststream.c
index 08b704928..a2fd830a9 100644
--- a/src/a2dp-faststream.c
+++ b/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"
@@ -221,6 +222,7 @@ void *a2dp_fs_enc_thread(struct ba_transport_pcm *t_pcm) {
 
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 			/* If the input buffer was not consumed (due to codesize limit), we
 			 * have to append new data to the existing one. Since we do not use
diff --git a/src/a2dp-lc3plus.c b/src/a2dp-lc3plus.c
index 66f782cfd..ebcea364f 100644
--- a/src/a2dp-lc3plus.c
+++ b/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"
@@ -377,6 +378,7 @@ void *a2dp_lc3plus_enc_thread(struct ba_transport_pcm *t_pcm) {
 
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 			/* If the input buffer was not consumed (due to codesize limit), we
 			 * have to append new data to the existing one. Since we do not use
diff --git a/src/a2dp-ldac.c b/src/a2dp-ldac.c
index 53004d615..75a166041 100644
--- a/src/a2dp-ldac.c
+++ b/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"
@@ -263,6 +264,7 @@ void *a2dp_ldac_enc_thread(struct ba_transport_pcm *t_pcm) {
 
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 		}
 
diff --git a/src/a2dp-lhdc.c b/src/a2dp-lhdc.c
index 3df791637..cf2ea5ec5 100644
--- a/src/a2dp-lhdc.c
+++ b/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"
@@ -294,6 +295,7 @@ void *a2dp_lhdc_enc_thread(struct ba_transport_pcm *t_pcm) {
 
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 		}
 
diff --git a/src/a2dp-mpeg.c b/src/a2dp-mpeg.c
index cf9cefc87..ed3b8f99a 100644
--- a/src/a2dp-mpeg.c
+++ b/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"
@@ -316,6 +317,7 @@ void *a2dp_mp3_enc_thread(struct ba_transport_pcm *t_pcm) {
 
 		/* update busy delay (encoding overhead) */
 		t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+		ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 		/* If the input buffer was not consumed (due to frame alignment), we
 		 * have to append new data to the existing one. Since we do not use
diff --git a/src/a2dp-opus.c b/src/a2dp-opus.c
index 2e82f86fb..da74ea87f 100644
--- a/src/a2dp-opus.c
+++ b/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"
@@ -237,6 +238,7 @@ void *a2dp_opus_enc_thread(struct ba_transport_pcm *t_pcm) {
 
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 			/* If the input buffer was not consumed (due to encoder frame
 			 * constraint), we have to append new data to the existing one.
diff --git a/src/a2dp-sbc.c b/src/a2dp-sbc.c
index b62a83d4f..1abd2109d 100644
--- a/src/a2dp-sbc.c
+++ b/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"
@@ -266,6 +267,7 @@ void *a2dp_sbc_enc_thread(struct ba_transport_pcm *t_pcm) {
 
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 			/* If the input buffer was not consumed (due to codesize limit), we
 			 * have to append new data to the existing one. Since we do not use
diff --git a/src/ba-transport-pcm.c b/src/ba-transport-pcm.c
index d9306aa14..7bf4917e9 100644
--- a/src/ba-transport-pcm.c
+++ b/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;
 }
 
diff --git a/src/ba-transport-pcm.h b/src/ba-transport-pcm.h
index acd1e9d85..7ff4f436c 100644
--- a/src/ba-transport-pcm.h
+++ b/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;
 
diff --git a/src/bluealsa-dbus.c b/src/bluealsa-dbus.c
index 431b1199d..f6283c244 100644
--- a/src/bluealsa-dbus.c
+++ b/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);
diff --git a/src/sco-cvsd.c b/src/sco-cvsd.c
index dea164c16..a769a9231 100644
--- a/src/sco-cvsd.c
+++ b/src/sco-cvsd.c
@@ -18,6 +18,7 @@
 
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-dbus.h"
 #include "io.h"
 #include "shared/defs.h"
 #include "shared/ffb.h"
@@ -80,6 +81,7 @@ void *sco_cvsd_enc_thread(struct ba_transport_pcm *t_pcm) {
 			asrsync_sync(&io.asrs, mtu_samples);
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 		}
 
diff --git a/src/sco-lc3-swb.c b/src/sco-lc3-swb.c
index b9efb590f..4b549188f 100644
--- a/src/sco-lc3-swb.c
+++ b/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"
@@ -86,6 +87,7 @@ void *sco_lc3_swb_enc_thread(struct ba_transport_pcm *t_pcm) {
 			asrsync_sync(&io.asrs, codec.frames * LC3_SWB_CODESAMPLES);
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 			/* Move unprocessed data to the front of our linear
 			 * buffer and clear the LC3-SWB frame counter. */
diff --git a/src/sco-msbc.c b/src/sco-msbc.c
index 3c9ceaae7..d2ec189bb 100644
--- a/src/sco-msbc.c
+++ b/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"
@@ -93,6 +94,7 @@ void *sco_msbc_enc_thread(struct ba_transport_pcm *t_pcm) {
 			asrsync_sync(&io.asrs, msbc.frames * MSBC_CODESAMPLES);
 			/* update busy delay (encoding overhead) */
 			t_pcm->processing_delay_dms = asrsync_get_busy_usec(&io.asrs) / 100;
+			ba_transport_pcm_delay_sync(t_pcm, BA_DBUS_PCM_UPDATE_DELAY);
 
 			/* Move unprocessed data to the front of our linear
 			 * buffer and clear the mSBC frame counter. */
diff --git a/test/test-a2dp.c b/test/test-a2dp.c
index c69f9828e..0c1c95d70 100644
--- a/test/test-a2dp.c
+++ b/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);