diff --git a/spa/plugins/bluez5/media-sink.c b/spa/plugins/bluez5/media-sink.c
index 5bc1811dd..3020edfd9 100644
--- a/spa/plugins/bluez5/media-sink.c
+++ b/spa/plugins/bluez5/media-sink.c
@@ -208,6 +208,8 @@ struct impl {
 
 	struct spa_bt_asha *asha;
 	struct spa_list asha_link;
+
+	struct spa_bt_latency tx_latency;
 };
 
 #define CHECK_PORT(this,d,p)	((d) == SPA_DIRECTION_INPUT && (p) == 0)
@@ -672,30 +674,41 @@ static int setup_matching(struct impl *this)
 	return 0;
 }
 
-static int get_transport_unused_size(struct impl *this)
+static int get_transport_unsent_size(struct impl *this)
 {
 	int res, value;
-	res = ioctl(this->flush_source.fd, TIOCOUTQ, &value);
-	if (res < 0) {
-		spa_log_error(this->log, "%p: ioctl fail: %m", this);
-		return -errno;
+
+	if (this->tx_latency.enabled) {
+		res = 0;
+		value = this->tx_latency.unsent;
+	} else {
+		res = ioctl(this->flush_source.fd, TIOCOUTQ, &value);
+		if (res < 0) {
+			spa_log_error(this->log, "%p: ioctl fail: %m", this);
+			return -errno;
+		}
+		if ((unsigned int)value > this->fd_buffer_size)
+			return -EIO;
+		value = this->fd_buffer_size - value;
 	}
-	spa_log_trace(this->log, "%p: fd unused buffer size:%d/%d", this, value, this->fd_buffer_size);
+
+	spa_log_trace(this->log, "%p: fd unsent size:%d/%d", this, value, this->fd_buffer_size);
 	return value;
 }
 
 static int send_buffer(struct impl *this)
 {
 	int written, unsent;
+	struct timespec ts_pre;
 
-	unsent = get_transport_unused_size(this);
-	if (unsent >= 0) {
-		unsent = this->fd_buffer_size - unsent;
+	unsent = get_transport_unsent_size(this);
+	if (unsent >= 0)
 		this->codec->abr_process(this->codec_data, unsent);
-	}
 
-	written = send(this->flush_source.fd, this->buffer,
-			this->buffer_used, MSG_DONTWAIT | MSG_NOSIGNAL);
+	spa_system_clock_gettime(this->data_system, CLOCK_REALTIME, &ts_pre);
+
+	written = spa_bt_send(this->flush_source.fd, this->buffer, this->buffer_used,
+			&this->tx_latency, SPA_TIMESPEC_TO_NSEC(&ts_pre));
 
 	if (SPA_UNLIKELY(spa_log_level_topic_enabled(this->log, SPA_LOG_TOPIC_DEFAULT, SPA_LOG_LEVEL_TRACE))) {
 		struct timespec ts;
@@ -855,7 +868,7 @@ static int flush_data(struct impl *this, uint64_t now_time)
 	bool is_asha = this->codec->asha;
 	uint32_t total_frames;
 	int written;
-	int unused_buffer;
+	int unsent_buffer;
 
 	spa_assert(this->transport_started);
 
@@ -994,11 +1007,10 @@ again:
 	}
 
 	/*
-	 * Get socket queue size before writing to it.
-	 * This should be the same as buffer size to increase bitpool
-	 * Bitpool shouldn't be increased when data is left over in the buffer
+	 * Get packet queue size before writing to it. This should be zero to increase
+	 * bitpool. Bitpool shouldn't be increased when there is unsent data.
 	 */
-	unused_buffer = get_transport_unused_size(this);
+	unsent_buffer = get_transport_unsent_size(this);
 
 	written = flush_buffer(this);
 
@@ -1075,7 +1087,7 @@ again:
 		}
 
 		if (now_time - this->last_error > SPA_NSEC_PER_SEC) {
-			if (unused_buffer == (int)this->fd_buffer_size) {
+			if (unsent_buffer == 0) {
 				int res = this->codec->increase_bitpool(this->codec_data);
 
 				spa_log_debug(this->log, "%p: increase bitpool: %i", this, res);
@@ -1209,9 +1221,13 @@ static void media_on_flush_error(struct spa_source *source)
 
 	if (source->rmask & SPA_IO_ERR) {
 		/* TX timestamp info? */
-		if (this->transport && this->transport->iso_io)
+		if (this->transport && this->transport->iso_io) {
 			if (spa_bt_iso_io_recv_errqueue(this->transport->iso_io) == 0)
 				return;
+		} else {
+			if (spa_bt_latency_recv_errqueue(&this->tx_latency, this->flush_source.fd, this->log) == 0)
+				return;
+		}
 
 		/* Otherwise: actual error */
 	}
@@ -1220,8 +1236,10 @@ static void media_on_flush_error(struct spa_source *source)
 
 	if (source->rmask & (SPA_IO_HUP | SPA_IO_ERR)) {
 		spa_log_warn(this->log, "%p: error %d", this, source->rmask);
-		if (this->flush_source.loop)
+		if (this->flush_source.loop) {
+			spa_bt_latency_flush(&this->tx_latency, this->flush_source.fd, this->log);
 			spa_loop_remove_source(this->data_loop, &this->flush_source);
+		}
 		enable_flush_timer(this, false);
 		if (this->flush_timer_source.loop)
 			spa_loop_remove_source(this->data_loop, &this->flush_timer_source);
@@ -1510,6 +1528,8 @@ static int transport_start(struct impl *this)
 		this->flush_timer_source.mask = SPA_IO_IN;
 		this->flush_timer_source.rmask = 0;
 		spa_loop_add_source(this->data_loop, &this->flush_timer_source);
+
+		spa_bt_latency_init(&this->tx_latency, this->transport, LATENCY_PERIOD, this->log);
 	}
 
 	if (!is_asha) {
@@ -1626,8 +1646,11 @@ static int do_remove_transport_source(struct spa_loop *loop,
 
 	this->transport_started = false;
 
-	if (this->flush_source.loop)
+	if (this->flush_source.loop) {
+		spa_bt_latency_flush(&this->tx_latency, this->flush_source.fd, this->log);
 		spa_loop_remove_source(this->data_loop, &this->flush_source);
+	}
+
 	if (this->flush_timer_source.loop)
 		spa_loop_remove_source(this->data_loop, &this->flush_timer_source);
 	if (this->codec->asha) {