Adding upstream version 0.3.65.upstream/0.3.65upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2151 insertions, 0 deletions

diff --git a/spa/plugins/bluez5/midi-node.c b/spa/plugins/bluez5/midi-node.c
new file mode 100644
index 0000000..c6a7e46
--- /dev/null
+++ b/spa/plugins/bluez5/midi-node.c
@@ -0,0 +1,2151 @@
+/* Spa MIDI node
+ *
+ * Copyright © 2022 Pauli Virtanen
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <unistd.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <spa/support/plugin.h>
+#include <spa/support/loop.h>
+#include <spa/support/log.h>
+#include <spa/support/system.h>
+#include <spa/utils/list.h>
+#include <spa/utils/keys.h>
+#include <spa/utils/names.h>
+#include <spa/utils/string.h>
+#include <spa/utils/result.h>
+#include <spa/utils/dll.h>
+#include <spa/utils/ringbuffer.h>
+#include <spa/monitor/device.h>
+#include <spa/control/control.h>
+
+#include <spa/node/node.h>
+#include <spa/node/utils.h>
+#include <spa/node/io.h>
+#include <spa/node/keys.h>
+#include <spa/param/param.h>
+#include <spa/param/latency-utils.h>
+#include <spa/param/audio/format.h>
+#include <spa/param/audio/format-utils.h>
+#include <spa/pod/filter.h>
+
+#include <spa/debug/mem.h>
+#include <spa/debug/log.h>
+
+#include "midi.h"
+
+#include "bluez5-interface-gen.h"
+
+static struct spa_log_topic log_topic = SPA_LOG_TOPIC(0, "spa.bluez5.midi.node");
+#undef SPA_LOG_TOPIC_DEFAULT
+#define SPA_LOG_TOPIC_DEFAULT &log_topic
+
+#define DEFAULT_CLOCK_NAME	"clock.system.monotonic"
+
+#define DLL_BW			0.05
+
+#define DEFAULT_LATENCY_OFFSET	(0 * SPA_NSEC_PER_MSEC)
+
+#define MAX_BUFFERS		32
+
+#define MIDI_RINGBUF_SIZE	(8192*4)
+
+enum node_role {
+	NODE_SERVER,
+	NODE_CLIENT,
+};
+
+struct props {
+	char clock_name[64];
+	char device_name[512];
+	int64_t latency_offset;
+};
+
+struct midi_event_ringbuffer_entry {
+	uint64_t time;
+	unsigned int size;
+};
+
+struct midi_event_ringbuffer {
+	struct spa_ringbuffer rbuf;
+	uint8_t buf[MIDI_RINGBUF_SIZE];
+};
+
+struct buffer {
+	uint32_t id;
+	unsigned int outgoing:1;
+	struct spa_buffer *buf;
+	struct spa_meta_header *h;
+	struct spa_list link;
+};
+
+struct time_sync {
+	uint64_t prev_recv_time;
+	uint64_t recv_time;
+
+	uint16_t prev_device_timestamp;
+	uint16_t device_timestamp;
+
+	uint64_t device_time;
+
+	struct spa_dll dll;
+};
+
+struct port {
+	uint32_t id;
+	enum spa_direction direction;
+
+	struct spa_audio_info current_format;
+	unsigned int have_format:1;
+
+	uint64_t info_all;
+	struct spa_port_info info;
+	struct spa_io_buffers *io;
+	struct spa_latency_info latency;
+#define IDX_EnumFormat	0
+#define IDX_Meta	1
+#define IDX_IO		2
+#define IDX_Format	3
+#define IDX_Buffers	4
+#define IDX_Latency	5
+#define N_PORT_PARAMS	6
+	struct spa_param_info params[N_PORT_PARAMS];
+
+	struct buffer buffers[MAX_BUFFERS];
+	uint32_t n_buffers;
+
+	struct spa_list free;
+	struct spa_list ready;
+
+	int fd;
+	uint16_t mtu;
+
+	struct buffer *buffer;
+	struct spa_pod_builder builder;
+	struct spa_pod_frame frame;
+
+	struct time_sync sync;
+
+	unsigned int acquired:1;
+	GCancellable *acquire_call;
+
+	struct spa_source source;
+
+	struct impl *impl;
+};
+
+struct impl {
+	struct spa_handle handle;
+	struct spa_node node;
+
+	struct spa_log *log;
+	struct spa_loop *main_loop;
+	struct spa_loop *data_loop;
+	struct spa_system *data_system;
+
+	GDBusConnection *conn;
+	Bluez5GattCharacteristic1 *proxy;
+
+	struct spa_hook_list hooks;
+	struct spa_callbacks callbacks;
+
+	uint64_t info_all;
+	struct spa_node_info info;
+#define IDX_PropInfo	0
+#define IDX_Props	1
+#define IDX_NODE_IO	2
+#define N_NODE_PARAMS	3
+	struct spa_param_info params[N_NODE_PARAMS];
+	struct props props;
+
+#define PORT_IN		0
+#define PORT_OUT	1
+#define N_PORTS		2
+	struct port ports[N_PORTS];
+
+	char *chr_path;
+
+	unsigned int started:1;
+	unsigned int following:1;
+
+	struct spa_source timer_source;
+
+	int timerfd;
+
+	struct spa_io_clock *clock;
+	struct spa_io_position *position;
+
+	uint32_t duration;
+	uint32_t rate;
+
+	uint64_t current_time;
+	uint64_t next_time;
+
+	struct midi_event_ringbuffer event_rbuf;
+
+	struct spa_bt_midi_parser parser;
+	struct spa_bt_midi_parser tmp_parser;
+	uint8_t read_buffer[MIDI_MAX_MTU];
+
+	struct spa_bt_midi_writer writer;
+
+	enum node_role role;
+
+	struct spa_bt_midi_server *server;
+};
+
+#define CHECK_PORT(this,d,p)	((p) == 0 && ((d) == SPA_DIRECTION_INPUT || (d) == SPA_DIRECTION_OUTPUT))
+#define GET_PORT(this,d,p)	(&(this)->ports[(d) == SPA_DIRECTION_OUTPUT ? PORT_OUT : PORT_IN])
+
+static void midi_event_ringbuffer_init(struct midi_event_ringbuffer *mbuf)
+{
+	spa_ringbuffer_init(&mbuf->rbuf);
+}
+
+static int midi_event_ringbuffer_push(struct midi_event_ringbuffer *mbuf,
+		uint64_t time, uint8_t *event, unsigned int size)
+{
+	const unsigned int bufsize = sizeof(mbuf->buf);
+	int32_t avail;
+	uint32_t index;
+	struct midi_event_ringbuffer_entry evt = {
+		.time = time,
+		.size = size
+	};
+
+	avail = spa_ringbuffer_get_write_index(&mbuf->rbuf, &index);
+	if (avail < 0 || avail + sizeof(evt) + size > bufsize)
+		return -ENOSPC;
+
+	spa_ringbuffer_write_data(&mbuf->rbuf, mbuf->buf, bufsize, index % bufsize,
+			&evt, sizeof(evt));
+	index += sizeof(evt);
+	spa_ringbuffer_write_update(&mbuf->rbuf, index);
+	spa_ringbuffer_write_data(&mbuf->rbuf, mbuf->buf, bufsize, index % bufsize,
+			event, size);
+	index += size;
+	spa_ringbuffer_write_update(&mbuf->rbuf, index);
+
+	return 0;
+}
+
+static int midi_event_ringbuffer_peek(struct midi_event_ringbuffer *mbuf, uint64_t *time, unsigned int *size)
+{
+	const unsigned bufsize = sizeof(mbuf->buf);
+	int32_t avail;
+	uint32_t index;
+	struct midi_event_ringbuffer_entry evt;
+
+	avail = spa_ringbuffer_get_read_index(&mbuf->rbuf, &index);
+	if (avail < (int)sizeof(evt))
+		return -ENOENT;
+
+	spa_ringbuffer_read_data(&mbuf->rbuf, mbuf->buf, bufsize, index % bufsize,
+					&evt, sizeof(evt));
+
+	*time = evt.time;
+	*size = evt.size;
+	return 0;
+}
+
+static int midi_event_ringbuffer_pop(struct midi_event_ringbuffer *mbuf, uint8_t *data, size_t max_size)
+{
+	const unsigned bufsize = sizeof(mbuf->buf);
+	int32_t avail;
+	uint32_t index;
+	struct midi_event_ringbuffer_entry evt;
+
+	avail = spa_ringbuffer_get_read_index(&mbuf->rbuf, &index);
+	if (avail < (int)sizeof(evt))
+		return -ENOENT;
+
+	spa_ringbuffer_read_data(&mbuf->rbuf, mbuf->buf, bufsize, index % bufsize,
+					&evt, sizeof(evt));
+	index += sizeof(evt);
+	avail -= sizeof(evt);
+	spa_ringbuffer_read_update(&mbuf->rbuf, index);
+
+	if ((uint32_t)avail < evt.size) {
+		/* corrupted ringbuffer: should never happen */
+		spa_assert_not_reached();
+		return -EINVAL;
+	}
+
+	if (evt.size <= max_size)
+		spa_ringbuffer_read_data(&mbuf->rbuf, mbuf->buf, bufsize, index % bufsize,
+				data, SPA_MIN(max_size, evt.size));
+	index += evt.size;
+	spa_ringbuffer_read_update(&mbuf->rbuf, index);
+
+	if (evt.size > max_size)
+		return -ENOSPC;
+
+	return 0;
+}
+
+static void reset_props(struct props *props)
+{
+	props->latency_offset = DEFAULT_LATENCY_OFFSET;
+	strncpy(props->clock_name, DEFAULT_CLOCK_NAME, sizeof(props->clock_name));
+	props->device_name[0] = '\0';
+}
+
+static bool is_following(struct impl *this)
+{
+	return this->position && this->clock && this->position->clock.id != this->clock->id;
+}
+
+static int set_timeout(struct impl *this, uint64_t time)
+{
+	struct itimerspec ts;
+	ts.it_value.tv_sec = time / SPA_NSEC_PER_SEC;
+	ts.it_value.tv_nsec = time % SPA_NSEC_PER_SEC;
+	ts.it_interval.tv_sec = 0;
+	ts.it_interval.tv_nsec = 0;
+	return spa_system_timerfd_settime(this->data_system,
+			this->timerfd, SPA_FD_TIMER_ABSTIME, &ts, NULL);
+}
+
+static int set_timers(struct impl *this)
+{
+	struct timespec now;
+
+	spa_system_clock_gettime(this->data_system, CLOCK_MONOTONIC, &now);
+	this->next_time = SPA_TIMESPEC_TO_NSEC(&now);
+
+	return set_timeout(this, this->following ? 0 : this->next_time);
+}
+
+static void recycle_buffer(struct impl *this, struct port *port, uint32_t buffer_id)
+{
+	struct buffer *b = &port->buffers[buffer_id];
+
+	if (b->outgoing) {
+		spa_log_trace(this->log, "%p: recycle buffer %u", this, buffer_id);
+		spa_list_append(&port->free, &b->link);
+		b->outgoing = false;
+	}
+}
+
+static int clear_buffers(struct impl *this, struct port *port)
+{
+	if (port->n_buffers > 0) {
+		spa_list_init(&port->free);
+		spa_list_init(&port->ready);
+		port->n_buffers = 0;
+	}
+	return 0;
+}
+
+static void reset_buffers(struct port *port)
+{
+	uint32_t i;
+
+	spa_list_init(&port->free);
+	spa_list_init(&port->ready);
+
+	for (i = 0; i < port->n_buffers; i++) {
+		struct buffer *b = &port->buffers[i];
+
+		if (port->direction == SPA_DIRECTION_OUTPUT) {
+			spa_list_append(&port->free, &b->link);
+			b->outgoing = false;
+		} else {
+			b->outgoing = true;
+		}
+	}
+}
+
+static struct buffer *peek_buffer(struct impl *this, struct port *port)
+{
+	if (spa_list_is_empty(&port->free))
+		return NULL;
+	return spa_list_first(&port->free, struct buffer, link);
+}
+
+static int prepare_buffer(struct impl *this, struct port *port)
+{
+	if (port->buffer != NULL)
+		return 0;
+	if ((port->buffer = peek_buffer(this, port)) == NULL)
+		return -EPIPE;
+
+	spa_pod_builder_init(&port->builder,
+			port->buffer->buf->datas[0].data,
+			port->buffer->buf->datas[0].maxsize);
+        spa_pod_builder_push_sequence(&port->builder, &port->frame, 0);
+
+	return 0;
+}
+
+static int finish_buffer(struct impl *this, struct port *port)
+{
+	if (port->buffer == NULL)
+		return 0;
+
+	spa_pod_builder_pop(&port->builder, &port->frame);
+
+	port->buffer->buf->datas[0].chunk->offset = 0;
+	port->buffer->buf->datas[0].chunk->size = port->builder.state.offset;
+
+	/* move buffer to ready queue */
+	spa_list_remove(&port->buffer->link);
+	spa_list_append(&port->ready, &port->buffer->link);
+	port->buffer = NULL;
+
+	return 0;
+}
+
+/* Replace value -> value + n*period, to minimize |value - target| */
+static int64_t unwrap_to_closest(int64_t value, int64_t target, int64_t period)
+{
+	if (value > target)
+		value -= SPA_ROUND_DOWN(value - target + period/2, period);
+	if (value < target)
+		value += SPA_ROUND_DOWN(target - value + period/2, period);
+	return value;
+}
+
+static int64_t time_diff(uint64_t a, uint64_t b)
+{
+	if (a >= b)
+		return a - b;
+	else
+		return -(int64_t)(b - a);
+}
+
+static void midi_event_get_last_timestamp(void *user_data, uint16_t timestamp, uint8_t *data, size_t size)
+{
+	int *last_timestamp = user_data;
+	*last_timestamp = timestamp;
+}
+
+static uint64_t midi_convert_time(struct time_sync *sync, uint16_t timestamp)
+{
+	int offset;
+
+	/*
+	 * sync->device_timestamp is a device timestamp that corresponds to system
+	 * clock time sync->device_time.
+	 *
+	 * It is the timestamp of the last MIDI event in the current packet, so we can
+	 * assume here no event here has timestamp after it.
+	 */
+	if (timestamp > sync->device_timestamp)
+		offset = sync->device_timestamp + MIDI_CLOCK_PERIOD_MSEC - timestamp;
+	else
+		offset = sync->device_timestamp - timestamp;
+
+	return sync->device_time - offset * SPA_NSEC_PER_MSEC;
+}
+
+static void midi_event_recv(void *user_data, uint16_t timestamp, uint8_t *data, size_t size)
+{
+	struct impl *this = user_data;
+	struct port *port = &this->ports[PORT_OUT];
+	struct time_sync *sync = &port->sync;
+	uint64_t time;
+	int res;
+
+	spa_assert(size > 0);
+
+	time = midi_convert_time(sync, timestamp);
+
+	spa_log_trace(this->log, "%p: event:0x%x size:%d timestamp:%d time:%"PRIu64"",
+			this, (int)data[0], (int)size, (int)timestamp, (uint64_t)time);
+
+	res = midi_event_ringbuffer_push(&this->event_rbuf, time, data, size);
+	if (res < 0) {
+		midi_event_ringbuffer_init(&this->event_rbuf);
+		spa_log_warn(this->log, "%p: MIDI receive buffer overflow: %s",
+				this, spa_strerror(res));
+	}
+}
+
+static int unacquire_port(struct port *port)
+{
+	struct impl *this = port->impl;
+
+	if (!port->acquired)
+		return 0;
+
+	spa_log_debug(this->log, "%p: unacquire port:%d", this, port->direction);
+
+	shutdown(port->fd, SHUT_RDWR);
+	close(port->fd);
+	port->fd = -1;
+	port->acquired = false;
+
+	if (this->server)
+		spa_bt_midi_server_released(this->server,
+				(port->direction == SPA_DIRECTION_OUTPUT));
+
+	return 0;
+}
+
+static int do_unacquire_port(struct spa_loop *loop, bool async, uint32_t seq,
+		const void *data, size_t size, void *user_data)
+{
+	struct port *port = user_data;
+
+	/* in main thread */
+	unacquire_port(port);
+	return 0;
+}
+
+static void on_ready_read(struct spa_source *source)
+{
+	struct port *port = source->data;
+	struct impl *this = port->impl;
+	struct timespec now;
+	int res, size, last_timestamp;
+
+	if (SPA_FLAG_IS_SET(source->rmask, SPA_IO_ERR) ||
+			SPA_FLAG_IS_SET(source->rmask, SPA_IO_HUP)) {
+		spa_log_debug(this->log, "%p: port:%d ERR/HUP", this, port->direction);
+		goto stop;
+	}
+
+	spa_system_clock_gettime(this->data_system, CLOCK_MONOTONIC, &now);
+
+	/* read data from socket */
+again:
+	size = recv(port->fd, this->read_buffer, sizeof(this->read_buffer), MSG_DONTWAIT | MSG_NOSIGNAL);
+	if (size == 0) {
+		return;
+	} else if (size < 0) {
+		if (errno == EINTR)
+			goto again;
+		if (errno == EAGAIN || errno == EWOULDBLOCK)
+			return;
+		goto stop;
+	}
+
+	spa_log_trace(this->log, "%p: port:%d recv data size:%d", this, port->direction, size);
+	spa_debug_log_mem(this->log, SPA_LOG_LEVEL_TRACE, 4, this->read_buffer, size);
+
+	if (port->direction != SPA_DIRECTION_OUTPUT) {
+		/* Just monitor errors for the input port */
+		spa_log_debug(this->log, "%p: port:%d is not RX port; ignoring data",
+				this, port->direction);
+		return;
+	}
+
+	/* prepare for producing events */
+	if (port->io == NULL || port->n_buffers == 0 || !this->started)
+		return;
+
+	/*
+	 * Remote clock synchronization:
+	 *
+	 * Assume: Last timestamp in packet on average corresponds to packet send time.
+	 * There is some unknown latency in between, but on average it is constant.
+	 *
+	 * The `device_time` computed below is the estimated wall-clock time
+	 * corresponding to the timestamp `device_timestamp` of the last event
+	 * in the packet. This timestamp is late by the average transmission latency,
+	 * which is unknown.
+	 *
+	 * Packet reception jitter and any clock drift is smoothed over with DLL.
+	 * The estimated timestamps are stable and preserve event intervals.
+	 *
+	 * To allow latency_offset to work better, we don't write the events
+	 * to the output buffer here, but instead put them to a ringbuffer.
+	 * This is because if the offset shifts events to later buffers,
+	 * this is simpler to handle with the rbuf.
+	 */
+	last_timestamp = -1;
+	spa_bt_midi_parser_dup(&this->parser, &this->tmp_parser, true);
+	res = spa_bt_midi_parser_parse(&this->tmp_parser, this->read_buffer, size, true,
+			midi_event_get_last_timestamp, &last_timestamp);
+	if (res >= 0 && last_timestamp >= 0) {
+		struct time_sync *sync = &port->sync;
+		int64_t clock_elapsed;
+		int64_t device_elapsed;
+		int64_t err_nsec;
+		double corr, tcorr;
+
+		sync->prev_recv_time = sync->recv_time;
+		sync->recv_time = SPA_TIMESPEC_TO_NSEC(&now);
+
+		sync->prev_device_timestamp = sync->device_timestamp;
+		sync->device_timestamp = last_timestamp;
+
+		if (port->sync.prev_recv_time == 0) {
+			sync->prev_recv_time = sync->recv_time;
+			sync->prev_device_timestamp = sync->device_timestamp;
+			spa_dll_init(&sync->dll);
+		}
+		if (SPA_UNLIKELY(sync->dll.bw == 0))
+			spa_dll_set_bw(&sync->dll, DLL_BW, 1024, 48000);
+
+		/* move device clock forward */
+		clock_elapsed = sync->recv_time - sync->prev_recv_time;
+
+		device_elapsed = (int)sync->device_timestamp - (int)sync->prev_device_timestamp;
+		device_elapsed *= SPA_NSEC_PER_MSEC;
+		device_elapsed = unwrap_to_closest(device_elapsed, clock_elapsed, MIDI_CLOCK_PERIOD_NSEC);
+		sync->device_time += device_elapsed;
+
+		/* smooth clock sync */
+		err_nsec = time_diff(sync->recv_time, sync->device_time);
+		corr = spa_dll_update(&sync->dll,
+				-SPA_CLAMP(err_nsec, -20*SPA_NSEC_PER_MSEC, 20*SPA_NSEC_PER_MSEC)
+				* this->rate / SPA_NSEC_PER_SEC);
+		tcorr = SPA_MIN(device_elapsed, SPA_NSEC_PER_SEC) * (corr - 1);
+		sync->device_time += tcorr;
+
+		/* reset if too much off */
+		if (err_nsec < -50 * SPA_NSEC_PER_MSEC ||
+				err_nsec > 200 * SPA_NSEC_PER_MSEC ||
+				SPA_ABS(tcorr) > 20*SPA_NSEC_PER_MSEC ||
+				device_elapsed < 0) {
+			spa_log_debug(this->log, "%p: device clock sync off too much: resync", this);
+			spa_dll_init(&sync->dll);
+			sync->device_time = sync->recv_time;
+		}
+
+		spa_log_debug(this->log,
+				"timestamp:%d dt:%d dt2:%d err:%.1f tcorr:%.2f (ms) corr:%f",
+				(int)sync->device_timestamp,
+				(int)(clock_elapsed/SPA_NSEC_PER_MSEC),
+				(int)(device_elapsed/SPA_NSEC_PER_MSEC),
+				(double)err_nsec / SPA_NSEC_PER_MSEC,
+				tcorr/SPA_NSEC_PER_MSEC,
+				corr);
+	}
+
+	/* put midi event data to the buffer */
+	res = spa_bt_midi_parser_parse(&this->parser, this->read_buffer, size, false,
+			midi_event_recv, this);
+	if (res < 0) {
+		/* bad data */
+		spa_bt_midi_parser_init(&this->parser);
+
+		spa_log_info(this->log, "BLE MIDI data packet parsing failed: %d", res);
+		spa_debug_log_mem(this->log, SPA_LOG_LEVEL_DEBUG, 4, this->read_buffer, size);
+	}
+
+	return;
+
+stop:
+	spa_log_debug(this->log, "%p: port:%d stopping port", this, port->direction);
+
+	if (port->source.loop)
+		spa_loop_remove_source(this->data_loop, &port->source);
+
+	/* port->acquired is updated only from the main thread */
+	spa_loop_invoke(this->main_loop, do_unacquire_port, 0, NULL, 0, false, port);
+}
+
+static int process_output(struct impl *this)
+{
+	struct port *port = &this->ports[PORT_OUT];
+	struct buffer *buffer;
+	struct spa_io_buffers *io = port->io;
+
+	/* Check if we are able to process */
+	if (io == NULL || !port->acquired)
+		return SPA_STATUS_OK;
+
+	/* Return if we already have a buffer */
+	if (io->status == SPA_STATUS_HAVE_DATA)
+		return SPA_STATUS_HAVE_DATA;
+
+	/* Recycle */
+	if (io->buffer_id < port->n_buffers) {
+		recycle_buffer(this, port, io->buffer_id);
+		io->buffer_id = SPA_ID_INVALID;
+	}
+
+	/* Produce buffer */
+	if (prepare_buffer(this, port) >= 0) {
+		/*
+		 * this->current_time is at the end time of the buffer, and offsets
+		 * are recorded vs. the start of the buffer.
+		 */
+		const uint64_t start_time = this->current_time
+			- this->duration * SPA_NSEC_PER_SEC / this->rate;
+		const uint64_t end_time = this->current_time;
+		uint64_t time;
+		uint32_t offset;
+		void *buf;
+		unsigned int size;
+		int res;
+
+		while (true) {
+			res = midi_event_ringbuffer_peek(&this->event_rbuf, &time, &size);
+			if (res < 0)
+				break;
+
+			time -= this->props.latency_offset;
+
+			if (time > end_time) {
+				break;
+			} else if (time + SPA_NSEC_PER_MSEC < start_time) {
+				/* Log events in the past by more than 1 ms, but don't
+				 * do anything about them. The user can change the latency
+				 * offset to choose whether to tradeoff latency for more
+				 * accurate timestamps.
+				 *
+				 * TODO: maybe this information should be available in
+				 * a more visible place, some latency property?
+				 */
+				spa_log_debug(this->log, "%p: event in the past by %d ms",
+						this, (int)((start_time - time) / SPA_NSEC_PER_MSEC));
+			}
+
+			time = SPA_MAX(time, start_time) - start_time;
+			offset = time * this->rate / SPA_NSEC_PER_SEC;
+			offset = SPA_CLAMP(offset, 0u, this->duration - 1);
+
+			spa_pod_builder_control(&port->builder, offset, SPA_CONTROL_Midi);
+			buf = spa_pod_builder_reserve_bytes(&port->builder, size);
+			if (buf) {
+				midi_event_ringbuffer_pop(&this->event_rbuf, buf, size);
+
+				spa_log_trace(this->log, "%p: produce event:0x%x offset:%d time:%"PRIu64"",
+						this, (int)*(uint8_t*)buf, (int)offset,
+						(uint64_t)(start_time + offset * SPA_NSEC_PER_SEC / this->rate));
+			}
+		}
+
+		finish_buffer(this, port);
+	}
+
+	/* Return if there are no buffers ready to be processed */
+	if (spa_list_is_empty(&port->ready))
+		return SPA_STATUS_OK;
+
+	/* Get the new buffer from the ready list */
+	buffer = spa_list_first(&port->ready, struct buffer, link);
+	spa_list_remove(&buffer->link);
+	buffer->outgoing = true;
+
+	/* Set the new buffer in IO */
+	io->buffer_id = buffer->id;
+	io->status = SPA_STATUS_HAVE_DATA;
+
+	/* Notify we have a buffer ready to be processed */
+	return SPA_STATUS_HAVE_DATA;
+}
+
+static int flush_packet(struct impl *this)
+{
+	struct port *port = &this->ports[PORT_IN];
+	int res;
+
+	if (this->writer.size == 0)
+		return 0;
+
+	res = send(port->fd, this->writer.buf, this->writer.size,
+			MSG_DONTWAIT | MSG_NOSIGNAL);
+	if (res < 0)
+		return -errno;
+
+	spa_log_trace(this->log, "%p: send packet size:%d", this, this->writer.size);
+	spa_debug_log_mem(this->log, SPA_LOG_LEVEL_TRACE, 4, this->writer.buf, this->writer.size);
+
+	return 0;
+}
+
+static int write_data(struct impl *this, struct spa_data *d)
+{
+	struct port *port = &this->ports[PORT_IN];
+	struct spa_pod_sequence *pod;
+	struct spa_pod_control *c;
+	uint64_t time;
+	int res;
+
+	pod = spa_pod_from_data(d->data, d->maxsize, d->chunk->offset, d->chunk->size);
+	if (pod == NULL) {
+		spa_log_warn(this->log, "%p: invalid sequence in buffer max:%u offset:%u size:%u",
+				this, d->maxsize, d->chunk->offset, d->chunk->size);
+		return -EINVAL;
+	}
+
+	spa_bt_midi_writer_init(&this->writer, port->mtu);
+	time = 0;
+
+	SPA_POD_SEQUENCE_FOREACH(pod, c) {
+		uint8_t *event;
+		size_t size;
+
+		if (c->type != SPA_CONTROL_Midi)
+			continue;
+
+		time = SPA_MAX(time, this->current_time + c->offset * SPA_NSEC_PER_SEC / this->rate);
+		event = SPA_POD_BODY(&c->value);
+		size = SPA_POD_BODY_SIZE(&c->value);
+
+		spa_log_trace(this->log, "%p: output event:0x%x time:%"PRIu64, this,
+				(size > 0) ? event[0] : 0, time);
+
+		do {
+			res = spa_bt_midi_writer_write(&this->writer,
+					time, event, size);
+			if (res < 0) {
+				return res;
+			} else if (res) {
+				int res2;
+				if ((res2 = flush_packet(this)) < 0)
+					return res2;
+			}
+		} while (res);
+	}
+
+	if ((res = flush_packet(this)) < 0)
+		return res;
+
+	return 0;
+}
+
+static int process_input(struct impl *this)
+{
+	struct port *port = &this->ports[PORT_IN];
+	struct buffer *b;
+	struct spa_io_buffers *io = port->io;
+	int res;
+
+	/* Check if we are able to process */
+	if (io == NULL || !port->acquired)
+		return SPA_STATUS_OK;
+
+	if (io->status != SPA_STATUS_HAVE_DATA || io->buffer_id >= port->n_buffers)
+		return SPA_STATUS_OK;
+
+	b = &port->buffers[io->buffer_id];
+	if (!b->outgoing) {
+		spa_log_warn(this->log, "%p: buffer %u not outgoing", this, io->buffer_id);
+		io->status = -EINVAL;
+		return -EINVAL;
+	}
+
+	if ((res = write_data(this, &b->buf->datas[0])) < 0) {
+		spa_log_info(this->log, "%p: writing data failed: %s",
+				this, spa_strerror(res));
+	}
+
+	port->io->buffer_id = b->id;
+	io->status = SPA_STATUS_NEED_DATA;
+	spa_node_call_reuse_buffer(&this->callbacks, 0, io->buffer_id);
+
+	return SPA_STATUS_HAVE_DATA;
+}
+
+static void update_position(struct impl *this)
+{
+	if (SPA_LIKELY(this->position)) {
+		this->duration = this->position->clock.duration;
+		this->rate = this->position->clock.rate.denom;
+	} else {
+		this->duration = 1024;
+		this->rate = 48000;
+	}
+}
+
+static void on_timeout(struct spa_source *source)
+{
+	struct impl *this = source->data;
+	uint64_t exp;
+	uint64_t prev_time, now_time;
+	int status;
+
+	if (!this->started)
+		return;
+
+	if (spa_system_timerfd_read(this->data_system, this->timerfd, &exp) < 0)
+		spa_log_warn(this->log, "%p: error reading timerfd: %s", this, strerror(errno));
+
+	prev_time = this->current_time;
+	now_time = this->current_time = this->next_time;
+
+	spa_log_trace(this->log, "%p: timer %"PRIu64" %"PRIu64"", this,
+			now_time, now_time - prev_time);
+
+	update_position(this);
+
+	this->next_time = now_time + this->duration * SPA_NSEC_PER_SEC / this->rate;
+
+	if (SPA_LIKELY(this->clock)) {
+		this->clock->nsec = now_time;
+		this->clock->position += this->duration;
+		this->clock->duration = this->duration;
+		this->clock->rate_diff = 1.0f;
+		this->clock->next_nsec = this->next_time;
+	}
+
+	status = process_output(this);
+	spa_log_trace(this->log, "%p: status:%d", this, status);
+
+	spa_node_call_ready(&this->callbacks, status | SPA_STATUS_NEED_DATA);
+
+	set_timeout(this, this->next_time);
+}
+
+static int do_start(struct impl *this);
+
+static int do_release(struct impl *this);
+
+static int do_stop(struct impl *this);
+
+static void acquire_reply(GObject *source_object, GAsyncResult *res, gpointer user_data, bool notify)
+{
+	struct port *port;
+	struct impl *this;
+	const char *method;
+	GError *err = NULL;
+	GUnixFDList *fd_list = NULL;
+	GVariant *fd_handle = NULL;
+	int fd;
+	guint16 mtu;
+
+	if (notify) {
+		bluez5_gatt_characteristic1_call_acquire_notify_finish(
+			BLUEZ5_GATT_CHARACTERISTIC1(source_object), &fd_handle, &mtu, &fd_list, res, &err);
+	} else {
+		bluez5_gatt_characteristic1_call_acquire_write_finish(
+			BLUEZ5_GATT_CHARACTERISTIC1(source_object), &fd_handle, &mtu, &fd_list, res, &err);
+	}
+
+	if (g_error_matches(err, G_IO_ERROR, G_IO_ERROR_CANCELLED)) {
+		/* Operation canceled: user_data may be invalid by now. */
+		g_error_free(err);
+		return;
+	}
+
+	port = user_data;
+	this = port->impl;
+	method = notify ? "AcquireNotify" : "AcquireWrite";
+	if (err) {
+		spa_log_error(this->log, "%s.%s() for %s failed: %s",
+				BLUEZ_GATT_CHR_INTERFACE, method,
+				this->chr_path, err->message);
+		goto fail;
+	}
+
+	fd = g_unix_fd_list_get(fd_list, g_variant_get_handle(fd_handle), &err);
+	if (fd < 0) {
+		spa_log_error(this->log, "%s.%s() for %s failed to get fd: %s",
+				BLUEZ_GATT_CHR_INTERFACE, method,
+				this->chr_path, err->message);
+		goto fail;
+	}
+
+	spa_log_info(this->log, "%p: BLE MIDI %s %s success mtu:%d",
+			this, this->chr_path, method, mtu);
+	port->fd = fd;
+	port->mtu = mtu;
+	port->acquired = true;
+
+	if (port->direction == SPA_DIRECTION_OUTPUT) {
+		spa_bt_midi_parser_init(&this->parser);
+
+		/* Start source */
+		port->source.data = port;
+		port->source.fd = port->fd;
+		port->source.func = on_ready_read;
+		port->source.mask = SPA_IO_IN | SPA_IO_HUP | SPA_IO_ERR;
+		port->source.rmask = 0;
+		spa_loop_add_source(this->data_loop, &port->source);
+	}
+	return;
+
+fail:
+	g_error_free(err);
+	g_clear_object(&fd_list);
+	g_clear_object(&fd_handle);
+	do_stop(this);
+	do_release(this);
+}
+
+static void acquire_notify_reply(GObject *source_object, GAsyncResult *res, gpointer user_data)
+{
+	acquire_reply(source_object, res, user_data, true);
+}
+
+static void acquire_write_reply(GObject *source_object, GAsyncResult *res, gpointer user_data)
+{
+	acquire_reply(source_object, res, user_data, false);
+}
+
+static int do_acquire(struct port *port)
+{
+	struct impl *this = port->impl;
+	const char *method = (port->direction == SPA_DIRECTION_OUTPUT) ?
+		"AcquireNotify" : "AcquireWrite";
+	GVariant *options;
+	GVariantBuilder builder;
+
+	if (port->acquired)
+		return 0;
+	if (port->acquire_call)
+		return 0;
+
+	spa_log_info(this->log,
+			"%p: port %d: client %s for BLE MIDI device characteristic %s",
+			this, port->direction, method, this->chr_path);
+
+	port->acquire_call = g_cancellable_new();
+
+	g_variant_builder_init(&builder, G_VARIANT_TYPE("a{sv}"));
+	options = g_variant_builder_end(&builder);
+
+	if (port->direction == SPA_DIRECTION_OUTPUT) {
+		bluez5_gatt_characteristic1_call_acquire_notify(
+				BLUEZ5_GATT_CHARACTERISTIC1(this->proxy),
+				options,
+				NULL,
+				port->acquire_call,
+				acquire_notify_reply,
+				port);
+	} else {
+		bluez5_gatt_characteristic1_call_acquire_write(
+				BLUEZ5_GATT_CHARACTERISTIC1(this->proxy),
+				options,
+				NULL,
+				port->acquire_call,
+				acquire_write_reply,
+				port);
+	}
+
+	return 0;
+}
+
+static int server_do_acquire(struct port *port, int fd, uint16_t mtu)
+{
+	struct impl *this = port->impl;
+	const char *method = (port->direction == SPA_DIRECTION_OUTPUT) ?
+		"AcquireWrite" : "AcquireNotify";
+
+	spa_log_info(this->log,
+			"%p: port %d: server %s for BLE MIDI device characteristic %s",
+			this, port->direction, method, this->server->chr_path);
+
+	if (port->acquired) {
+		spa_log_info(this->log,
+				"%p: port %d: %s failed: already acquired",
+				this, port->direction, method);
+		return -EBUSY;
+	}
+
+	port->fd = fd;
+	port->mtu = mtu;
+
+	if (port->direction == SPA_DIRECTION_OUTPUT)
+		spa_bt_midi_parser_init(&this->parser);
+
+	/* Start source */
+	port->source.data = port;
+	port->source.fd = port->fd;
+	port->source.func = on_ready_read;
+	port->source.mask = SPA_IO_HUP | SPA_IO_ERR;
+	if (port->direction == SPA_DIRECTION_OUTPUT)
+		port->source.mask |= SPA_IO_IN;
+	port->source.rmask = 0;
+	spa_loop_add_source(this->data_loop, &port->source);
+
+	port->acquired = true;
+	return 0;
+}
+
+static int server_acquire_write(void *user_data, int fd, uint16_t mtu)
+{
+	struct impl *this = user_data;
+	return server_do_acquire(&this->ports[PORT_OUT], fd, mtu);
+}
+
+static int server_acquire_notify(void *user_data, int fd, uint16_t mtu)
+{
+	struct impl *this = user_data;
+	return server_do_acquire(&this->ports[PORT_IN], fd, mtu);
+}
+
+static int server_release(void *user_data)
+{
+	struct impl *this = user_data;
+	do_release(this);
+	return 0;
+}
+
+static const char *server_description(void *user_data)
+{
+	struct impl *this = user_data;
+	return this->props.device_name;
+}
+
+static int do_remove_port_source(struct spa_loop *loop,
+		bool async, uint32_t seq, const void *data, size_t size, void *user_data)
+{
+	struct impl *this = user_data;
+	int i;
+
+	for (i = 0; i < N_PORTS; ++i) {
+		struct port *port = &this->ports[i];
+
+		if (port->source.loop)
+			spa_loop_remove_source(this->data_loop, &port->source);
+	}
+
+	return 0;
+}
+
+static int do_remove_source(struct spa_loop *loop,
+		bool async,
+		uint32_t seq,
+		const void *data,
+		size_t size,
+		void *user_data)
+{
+	struct impl *this = user_data;
+	struct itimerspec ts;
+
+	if (this->timer_source.loop)
+		spa_loop_remove_source(this->data_loop, &this->timer_source);
+
+	ts.it_value.tv_sec = 0;
+	ts.it_value.tv_nsec = 0;
+	ts.it_interval.tv_sec = 0;
+	ts.it_interval.tv_nsec = 0;
+	spa_system_timerfd_settime(this->data_system, this->timerfd, 0, &ts, NULL);
+
+	return 0;
+}
+
+static int do_stop(struct impl *this)
+{
+	int res = 0;
+
+	spa_log_debug(this->log, "%p: stop", this);
+
+	spa_loop_invoke(this->data_loop, do_remove_source, 0, NULL, 0, true, this);
+
+	this->started = false;
+
+	return res;
+}
+
+static int do_release(struct impl *this)
+{
+	int res = 0;
+	size_t i;
+
+	spa_log_debug(this->log, "%p: release", this);
+
+	spa_loop_invoke(this->data_loop, do_remove_port_source, 0, NULL, 0, true, this);
+
+	for (i = 0; i < N_PORTS; ++i) {
+		struct port *port = &this->ports[i];
+
+		g_cancellable_cancel(port->acquire_call);
+		g_clear_object(&port->acquire_call);
+
+		unacquire_port(port);
+	}
+
+	return res;
+}
+
+static int do_start(struct impl *this)
+{
+	int res;
+	size_t i;
+
+	if (this->started)
+		return 0;
+
+	this->following = is_following(this);
+
+	update_position(this);
+
+	spa_log_debug(this->log, "%p: start following:%d",
+			this, this->following);
+
+	for (i = 0; i < N_PORTS; ++i) {
+		struct port *port = &this->ports[i];
+
+		switch (this->role) {
+		case NODE_CLIENT:
+			/* Acquire Bluetooth I/O */
+			if ((res = do_acquire(port)) < 0) {
+				do_stop(this);
+				do_release(this);
+				return res;
+			}
+			break;
+		case NODE_SERVER:
+			/*
+			 * In MIDI server role, the device/BlueZ invokes
+			 * the acquire asynchronously as available/needed.
+			 */
+			break;
+		default:
+			spa_assert_not_reached();
+		}
+
+		reset_buffers(port);
+	}
+
+	midi_event_ringbuffer_init(&this->event_rbuf);
+
+	this->started = true;
+
+	/* Start timer */
+	this->timer_source.data = this;
+	this->timer_source.fd = this->timerfd;
+	this->timer_source.func = on_timeout;
+	this->timer_source.mask = SPA_IO_IN;
+	this->timer_source.rmask = 0;
+	spa_loop_add_source(this->data_loop, &this->timer_source);
+
+	set_timers(this);
+
+	return 0;
+}
+
+
+static int do_reassign_follower(struct spa_loop *loop,
+		bool async,
+		uint32_t seq,
+		const void *data,
+		size_t size,
+		void *user_data)
+{
+	struct impl *this = user_data;
+
+	set_timers(this);
+	return 0;
+}
+
+static int impl_node_set_io(void *object, uint32_t id, void *data, size_t size)
+{
+	struct impl *this = object;
+	bool following;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+
+	switch (id) {
+	case SPA_IO_Clock:
+		this->clock = data;
+		if (this->clock != NULL) {
+			spa_scnprintf(this->clock->name,
+					sizeof(this->clock->name),
+					"%s", this->props.clock_name);
+		}
+		break;
+	case SPA_IO_Position:
+		this->position = data;
+		break;
+	default:
+		return -ENOENT;
+	}
+
+	following = is_following(this);
+	if (this->started && following != this->following) {
+		spa_log_debug(this->log, "%p: reassign follower %d->%d", this, this->following, following);
+		this->following = following;
+		spa_loop_invoke(this->data_loop, do_reassign_follower, 0, NULL, 0, true, this);
+	}
+
+	return 0;
+}
+
+static void emit_node_info(struct impl *this, bool full);
+
+static int impl_node_enum_params(void *object, int seq,
+		uint32_t id, uint32_t start, uint32_t num,
+		const struct spa_pod *filter)
+{
+	struct impl *this = object;
+	struct spa_pod *param;
+	struct spa_pod_builder b = { 0 };
+	uint8_t buffer[1024];
+	struct spa_result_node_params result;
+	uint32_t count = 0;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+	spa_return_val_if_fail(num != 0, -EINVAL);
+
+	result.id = id;
+	result.next = start;
+next:
+	result.index = result.next++;
+
+	spa_pod_builder_init(&b, buffer, sizeof(buffer));
+
+	switch (id) {
+	case SPA_PARAM_PropInfo:
+	{
+		struct props *p = &this->props;
+
+		switch (result.index) {
+		case 0:
+			param = spa_pod_builder_add_object(&b,
+				SPA_TYPE_OBJECT_PropInfo, id,
+				SPA_PROP_INFO_id,   SPA_POD_Id(SPA_PROP_latencyOffsetNsec),
+				SPA_PROP_INFO_description, SPA_POD_String("Latency offset (ns)"),
+				SPA_PROP_INFO_type, SPA_POD_CHOICE_RANGE_Long(0LL, INT64_MIN, INT64_MAX));
+			break;
+		case 1:
+			param = spa_pod_builder_add_object(&b,
+				SPA_TYPE_OBJECT_PropInfo, id,
+				SPA_PROP_INFO_id,   SPA_POD_Id(SPA_PROP_deviceName),
+				SPA_PROP_INFO_description, SPA_POD_String("Device name"),
+				SPA_PROP_INFO_type, SPA_POD_String(p->device_name));
+			break;
+		default:
+			return 0;
+		}
+		break;
+	}
+	case SPA_PARAM_Props:
+	{
+		struct props *p = &this->props;
+
+		switch (result.index) {
+		case 0:
+			param = spa_pod_builder_add_object(&b,
+				SPA_TYPE_OBJECT_Props, id,
+				SPA_PROP_latencyOffsetNsec, SPA_POD_Long(p->latency_offset),
+				SPA_PROP_deviceName, SPA_POD_String(p->device_name));
+			break;
+		default:
+			return 0;
+		}
+		break;
+	}
+	default:
+		return -ENOENT;
+	}
+
+	if (spa_pod_filter(&b, &result.param, param, filter) < 0)
+		goto next;
+
+	spa_node_emit_result(&this->hooks, seq, 0, SPA_RESULT_TYPE_NODE_PARAMS, &result);
+
+	if (++count != num)
+		goto next;
+
+	return 0;
+}
+
+static void emit_port_info(struct impl *this, struct port *port, bool full);
+
+static void set_latency(struct impl *this, bool emit_latency)
+{
+	struct port *port = &this->ports[PORT_OUT];
+
+	port->latency.min_ns = port->latency.max_ns = this->props.latency_offset;
+
+	if (emit_latency) {
+		port->info.change_mask |= SPA_PORT_CHANGE_MASK_PARAMS;
+		port->params[IDX_Latency].flags ^= SPA_PARAM_INFO_SERIAL;
+		emit_port_info(this, port, false);
+	}
+}
+
+static int apply_props(struct impl *this, const struct spa_pod *param)
+{
+	struct props new_props = this->props;
+	int changed = 0;
+
+	if (param == NULL) {
+		reset_props(&new_props);
+	} else {
+		spa_pod_parse_object(param,
+				SPA_TYPE_OBJECT_Props, NULL,
+				SPA_PROP_latencyOffsetNsec, SPA_POD_OPT_Long(&new_props.latency_offset),
+				SPA_PROP_deviceName, SPA_POD_OPT_Stringn(new_props.device_name,
+						sizeof(new_props.device_name)));
+	}
+
+	changed = (memcmp(&new_props, &this->props, sizeof(struct props)) != 0);
+	this->props = new_props;
+
+	if (changed)
+		set_latency(this, true);
+
+	return changed;
+}
+
+static int impl_node_set_param(void *object, uint32_t id, uint32_t flags,
+		const struct spa_pod *param)
+{
+	struct impl *this = object;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+
+	switch (id) {
+	case SPA_PARAM_Props:
+	{
+		if (apply_props(this, param) > 0) {
+			this->info.change_mask |= SPA_NODE_CHANGE_MASK_PARAMS;
+			this->params[IDX_Props].flags ^= SPA_PARAM_INFO_SERIAL;
+			emit_node_info(this, false);
+		}
+		break;
+	}
+	default:
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+static int impl_node_send_command(void *object, const struct spa_command *command)
+{
+	struct impl *this = object;
+	int res, res2;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+	spa_return_val_if_fail(command != NULL, -EINVAL);
+
+	switch (SPA_NODE_COMMAND_ID(command)) {
+	case SPA_NODE_COMMAND_Start:
+		if ((res = do_start(this)) < 0)
+			return res;
+		break;
+	case SPA_NODE_COMMAND_Pause:
+		if ((res = do_stop(this)) < 0)
+			return res;
+		break;
+	case SPA_NODE_COMMAND_Suspend:
+		res = do_stop(this);
+		if (this->role == NODE_CLIENT)
+			res2 = do_release(this);
+		else
+			res2 = 0;
+		if (res < 0)
+			return res;
+		if (res2 < 0)
+			return res2;
+		break;
+	default:
+		return -ENOTSUP;
+	}
+	return 0;
+}
+
+static void emit_node_info(struct impl *this, bool full)
+{
+	const struct spa_dict_item node_info_items[] = {
+		{ SPA_KEY_DEVICE_API, "bluez5" },
+		{ SPA_KEY_MEDIA_CLASS, "Midi/Bridge" },
+	};
+	uint64_t old = full ? this->info.change_mask : 0;
+
+	if (full)
+		this->info.change_mask = this->info_all;
+	if (this->info.change_mask) {
+		this->info.props =  &SPA_DICT_INIT_ARRAY(node_info_items);
+		spa_node_emit_info(&this->hooks, &this->info);
+		this->info.change_mask = old;
+	}
+}
+
+static void emit_port_info(struct impl *this, struct port *port, bool full)
+{
+	uint64_t old = full ? port->info.change_mask : 0;
+	if (full)
+		port->info.change_mask = port->info_all;
+	if (port->info.change_mask) {
+		spa_node_emit_port_info(&this->hooks, port->direction, port->id, &port->info);
+		port->info.change_mask = old;
+	}
+}
+
+static int
+impl_node_add_listener(void *object,
+		struct spa_hook *listener,
+		const struct spa_node_events *events,
+		void *data)
+{
+	struct impl *this = object;
+	struct spa_hook_list save;
+	size_t i;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+
+	spa_hook_list_isolate(&this->hooks, &save, listener, events, data);
+
+	emit_node_info(this, true);
+
+	for (i = 0; i < N_PORTS; ++i)
+		emit_port_info(this, &this->ports[i], true);
+
+	spa_hook_list_join(&this->hooks, &save);
+
+	return 0;
+}
+
+static int
+impl_node_set_callbacks(void *object,
+		const struct spa_node_callbacks *callbacks,
+		void *data)
+{
+	struct impl *this = object;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+
+	this->callbacks = SPA_CALLBACKS_INIT(callbacks, data);
+
+	return 0;
+}
+
+static int impl_node_sync(void *object, int seq)
+{
+	struct impl *this = object;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+
+	spa_node_emit_result(&this->hooks, seq, 0, 0, NULL);
+
+	return 0;
+}
+
+static int impl_node_add_port(void *object, enum spa_direction direction, uint32_t port_id,
+		const struct spa_dict *props)
+{
+	return -ENOTSUP;
+}
+
+static int impl_node_remove_port(void *object, enum spa_direction direction, uint32_t port_id)
+{
+	return -ENOTSUP;
+}
+
+static int
+impl_node_port_enum_params(void *object, int seq,
+		enum spa_direction direction, uint32_t port_id,
+		uint32_t id, uint32_t start, uint32_t num,
+		const struct spa_pod *filter)
+{
+
+	struct impl *this = object;
+	struct port *port;
+	struct spa_pod *param;
+	struct spa_pod_builder b = { 0 };
+	uint8_t buffer[1024];
+	struct spa_result_node_params result;
+	uint32_t count = 0;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+	spa_return_val_if_fail(num != 0, -EINVAL);
+
+	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
+
+	port = GET_PORT(this, direction, port_id);
+
+	result.id = id;
+	result.next = start;
+next:
+	result.index = result.next++;
+
+	spa_pod_builder_init(&b, buffer, sizeof(buffer));
+
+	switch (id) {
+	case SPA_PARAM_EnumFormat:
+		if (result.index > 0)
+			return 0;
+
+		param = spa_pod_builder_add_object(&b,
+				SPA_TYPE_OBJECT_Format, SPA_PARAM_EnumFormat,
+				SPA_FORMAT_mediaType,	   SPA_POD_Id(SPA_MEDIA_TYPE_application),
+				SPA_FORMAT_mediaSubtype,   SPA_POD_Id(SPA_MEDIA_SUBTYPE_control));
+		break;
+
+	case SPA_PARAM_Format:
+		if (!port->have_format)
+			return -EIO;
+		if (result.index > 0)
+			return 0;
+
+		param = spa_pod_builder_add_object(&b,
+				SPA_TYPE_OBJECT_Format, SPA_PARAM_Format,
+				SPA_FORMAT_mediaType,	   SPA_POD_Id(SPA_MEDIA_TYPE_application),
+				SPA_FORMAT_mediaSubtype,   SPA_POD_Id(SPA_MEDIA_SUBTYPE_control));
+		break;
+
+	case SPA_PARAM_Buffers:
+		if (!port->have_format)
+			return -EIO;
+		if (result.index > 0)
+			return 0;
+
+		param = spa_pod_builder_add_object(&b,
+				SPA_TYPE_OBJECT_ParamBuffers, id,
+				SPA_PARAM_BUFFERS_buffers, SPA_POD_CHOICE_RANGE_Int(2, 1, MAX_BUFFERS),
+				SPA_PARAM_BUFFERS_blocks,  SPA_POD_Int(1),
+				SPA_PARAM_BUFFERS_size,	   SPA_POD_CHOICE_RANGE_Int(
+					4096, 4096, INT32_MAX),
+				SPA_PARAM_BUFFERS_stride,  SPA_POD_Int(1));
+		break;
+
+	case SPA_PARAM_Meta:
+		switch (result.index) {
+		case 0:
+			param = spa_pod_builder_add_object(&b,
+					SPA_TYPE_OBJECT_ParamMeta, id,
+					SPA_PARAM_META_type, SPA_POD_Id(SPA_META_Header),
+					SPA_PARAM_META_size, SPA_POD_Int(sizeof(struct spa_meta_header)));
+			break;
+		default:
+			return 0;
+		}
+		break;
+
+	case SPA_PARAM_IO:
+		switch (result.index) {
+		case 0:
+			param = spa_pod_builder_add_object(&b,
+					SPA_TYPE_OBJECT_ParamIO, id,
+					SPA_PARAM_IO_id,   SPA_POD_Id(SPA_IO_Buffers),
+					SPA_PARAM_IO_size, SPA_POD_Int(sizeof(struct spa_io_buffers)));
+			break;
+		default:
+			return 0;
+		}
+		break;
+
+	case SPA_PARAM_Latency:
+		switch (result.index) {
+		case 0:
+			param = spa_latency_build(&b, id, &port->latency);
+			break;
+		default:
+			return 0;
+		}
+		break;
+
+	default:
+		return -ENOENT;
+	}
+
+	if (spa_pod_filter(&b, &result.param, param, filter) < 0)
+		goto next;
+
+	spa_node_emit_result(&this->hooks, seq, 0, SPA_RESULT_TYPE_NODE_PARAMS, &result);
+
+	if (++count != num)
+		goto next;
+
+	return 0;
+}
+
+static int port_set_format(struct impl *this, struct port *port,
+		uint32_t flags,
+		const struct spa_pod *format)
+{
+	int err;
+
+	if (format == NULL) {
+		if (!port->have_format)
+			return 0;
+
+		clear_buffers(this, port);
+		port->have_format = false;
+	} else {
+		struct spa_audio_info info = { 0 };
+
+		if ((err = spa_format_parse(format, &info.media_type, &info.media_subtype)) < 0)
+			return err;
+
+		if (info.media_type != SPA_MEDIA_TYPE_application ||
+		    info.media_subtype != SPA_MEDIA_SUBTYPE_control)
+			return -EINVAL;
+
+		port->current_format = info;
+		port->have_format = true;
+	}
+
+	port->info.change_mask |= SPA_PORT_CHANGE_MASK_RATE;
+	port->info.rate = SPA_FRACTION(1, 1);
+	port->info.change_mask |= SPA_PORT_CHANGE_MASK_PARAMS;
+	if (port->have_format) {
+		port->params[IDX_Format] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_READWRITE);
+		port->params[IDX_Buffers] = SPA_PARAM_INFO(SPA_PARAM_Buffers, SPA_PARAM_INFO_READ);
+	} else {
+		port->params[IDX_Format] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
+		port->params[IDX_Buffers] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
+	}
+	emit_port_info(this, port, false);
+
+	return 0;
+}
+
+static int
+impl_node_port_set_param(void *object,
+		enum spa_direction direction, uint32_t port_id,
+		uint32_t id, uint32_t flags,
+		const struct spa_pod *param)
+{
+	struct impl *this = object;
+	struct port *port;
+	int res;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+
+	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
+
+	port = GET_PORT(this, direction, port_id);
+
+	switch (id) {
+	case SPA_PARAM_Format:
+		res = port_set_format(this, port, flags, param);
+		break;
+	case SPA_PARAM_Latency:
+		res = 0;
+		break;
+	default:
+		res = -ENOENT;
+		break;
+	}
+	return res;
+}
+
+static int
+impl_node_port_use_buffers(void *object,
+		enum spa_direction direction, uint32_t port_id,
+		uint32_t flags,
+		struct spa_buffer **buffers, uint32_t n_buffers)
+{
+	struct impl *this = object;
+	struct port *port;
+	uint32_t i;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+
+	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
+
+	port = GET_PORT(this, direction, port_id);
+
+	spa_log_debug(this->log, "%p: use buffers %d", this, n_buffers);
+
+	if (!port->have_format)
+		return -EIO;
+
+	clear_buffers(this, port);
+
+	for (i = 0; i < n_buffers; i++) {
+		struct buffer *b = &port->buffers[i];
+		struct spa_data *d = buffers[i]->datas;
+
+		b->buf = buffers[i];
+		b->id = i;
+
+		b->h = spa_buffer_find_meta_data(buffers[i], SPA_META_Header, sizeof(*b->h));
+
+		if (d[0].data == NULL) {
+			spa_log_error(this->log, "%p: need mapped memory", this);
+			return -EINVAL;
+		}
+	}
+	port->n_buffers = n_buffers;
+
+	reset_buffers(port);
+
+	return 0;
+}
+
+static int
+impl_node_port_set_io(void *object,
+		enum spa_direction direction,
+		uint32_t port_id,
+		uint32_t id,
+		void *data, size_t size)
+{
+	struct impl *this = object;
+	struct port *port;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+
+	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
+
+	port = GET_PORT(this, direction, port_id);
+
+	switch (id) {
+	case SPA_IO_Buffers:
+		port->io = data;
+		break;
+	default:
+		return -ENOENT;
+	}
+	return 0;
+}
+
+static int impl_node_port_reuse_buffer(void *object, uint32_t port_id, uint32_t buffer_id)
+{
+	struct impl *this = object;
+	struct port *port;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+
+	spa_return_val_if_fail(CHECK_PORT(this, SPA_DIRECTION_OUTPUT, port_id), -EINVAL);
+
+	port = GET_PORT(this, SPA_DIRECTION_OUTPUT, port_id);
+
+	if (port->n_buffers == 0)
+		return -EIO;
+
+	if (buffer_id >= port->n_buffers)
+		return -EINVAL;
+
+	recycle_buffer(this, port, buffer_id);
+
+	return 0;
+}
+
+static int impl_node_process(void *object)
+{
+	struct impl *this = object;
+	int status = SPA_STATUS_OK;
+
+	spa_return_val_if_fail(this != NULL, -EINVAL);
+
+	if (!this->started)
+		return SPA_STATUS_OK;
+
+	if (this->following) {
+		if (this->position) {
+			this->current_time = this->position->clock.nsec;
+		} else {
+			struct timespec now = { 0 };
+			spa_system_clock_gettime(this->data_system, CLOCK_MONOTONIC, &now);
+			this->current_time = SPA_TIMESPEC_TO_NSEC(&now);
+		}
+	}
+
+	update_position(this);
+
+	if (this->following)
+		status |= process_output(this);
+
+	status |= process_input(this);
+
+	return status;
+}
+
+static const struct spa_node_methods impl_node = {
+	SPA_VERSION_NODE_METHODS,
+	.add_listener = impl_node_add_listener,
+	.set_callbacks = impl_node_set_callbacks,
+	.sync = impl_node_sync,
+	.enum_params = impl_node_enum_params,
+	.set_param = impl_node_set_param,
+	.set_io = impl_node_set_io,
+	.send_command = impl_node_send_command,
+	.add_port = impl_node_add_port,
+	.remove_port = impl_node_remove_port,
+	.port_enum_params = impl_node_port_enum_params,
+	.port_set_param = impl_node_port_set_param,
+	.port_use_buffers = impl_node_port_use_buffers,
+	.port_set_io = impl_node_port_set_io,
+	.port_reuse_buffer = impl_node_port_reuse_buffer,
+	.process = impl_node_process,
+};
+
+static const struct spa_bt_midi_server_cb impl_server = {
+	.acquire_write = server_acquire_write,
+	.acquire_notify = server_acquire_notify,
+	.release = server_release,
+	.get_description = server_description,
+};
+
+static int impl_get_interface(struct spa_handle *handle, const char *type, void **interface)
+{
+	struct impl *this;
+
+	spa_return_val_if_fail(handle != NULL, -EINVAL);
+	spa_return_val_if_fail(interface != NULL, -EINVAL);
+
+	this = (struct impl *) handle;
+
+	if (spa_streq(type, SPA_TYPE_INTERFACE_Node))
+		*interface = &this->node;
+	else
+		return -ENOENT;
+
+	return 0;
+}
+
+static int impl_clear(struct spa_handle *handle)
+{
+	struct impl *this = (struct impl *) handle;
+
+	do_stop(this);
+	do_release(this);
+
+	free(this->chr_path);
+	if (this->timerfd > 0)
+		spa_system_close(this->data_system, this->timerfd);
+	if (this->server)
+		spa_bt_midi_server_destroy(this->server);
+	g_clear_object(&this->proxy);
+	g_clear_object(&this->conn);
+
+	spa_zero(*this);
+
+	return 0;
+}
+
+static size_t
+impl_get_size(const struct spa_handle_factory *factory,
+		const struct spa_dict *params)
+{
+	return sizeof(struct impl);
+}
+
+static int
+impl_init(const struct spa_handle_factory *factory,
+		struct spa_handle *handle,
+		const struct spa_dict *info,
+		const struct spa_support *support,
+		uint32_t n_support)
+{
+	struct impl *this;
+	const char *device_name = "";
+	int res = 0;
+	GError *err = NULL;
+	size_t i;
+
+	spa_return_val_if_fail(factory != NULL, -EINVAL);
+	spa_return_val_if_fail(handle != NULL, -EINVAL);
+
+	handle->get_interface = impl_get_interface;
+	handle->clear = impl_clear;
+
+	this = (struct impl *) handle;
+
+	this->log = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_Log);
+	this->main_loop = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_Loop);
+	this->data_loop = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_DataLoop);
+	this->data_system = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_DataSystem);
+
+	if (this->log == NULL)
+		return -EINVAL;
+
+	spa_log_topic_init(this->log, &log_topic);
+
+	if (!(info && spa_atob(spa_dict_lookup(info, SPA_KEY_API_GLIB_MAINLOOP)))) {
+		spa_log_error(this->log, "Glib mainloop is not usable: %s not set",
+				SPA_KEY_API_GLIB_MAINLOOP);
+		return -EINVAL;
+	}
+
+	if (this->data_loop == NULL) {
+		spa_log_error(this->log, "a data loop is needed");
+		return -EINVAL;
+	}
+	if (this->data_system == NULL) {
+		spa_log_error(this->log, "a data system is needed");
+		return -EINVAL;
+	}
+
+	this->role = NODE_CLIENT;
+
+	if (info) {
+		const char *str;
+
+		if ((str = spa_dict_lookup(info, SPA_KEY_API_BLUEZ5_PATH)) != NULL)
+			this->chr_path = strdup(str);
+
+		if ((str = spa_dict_lookup(info, SPA_KEY_API_BLUEZ5_ROLE)) != NULL) {
+			if (spa_streq(str, "server"))
+				this->role = NODE_SERVER;
+		}
+
+		if ((str = spa_dict_lookup(info, "node.nick")) != NULL)
+			device_name = str;
+		else if ((str = spa_dict_lookup(info, "node.description")) != NULL)
+			device_name = str;
+	}
+
+	if (this->role == NODE_CLIENT && this->chr_path == NULL) {
+		spa_log_error(this->log, "missing MIDI service characteristic path");
+		res = -EINVAL;
+		goto fail;
+	}
+
+	this->conn = g_bus_get_sync(G_BUS_TYPE_SYSTEM, NULL, &err);
+	if (this->conn == NULL) {
+		spa_log_error(this->log, "failed to get dbus connection: %s",
+				err->message);
+		g_error_free(err);
+		res = -EIO;
+		goto fail;
+	}
+
+	this->node.iface = SPA_INTERFACE_INIT(
+		SPA_TYPE_INTERFACE_Node,
+				SPA_VERSION_NODE,
+				&impl_node, this);
+	spa_hook_list_init(&this->hooks);
+
+	reset_props(&this->props);
+
+	spa_scnprintf(this->props.device_name, sizeof(this->props.device_name),
+			"%s", device_name);
+
+	/* set the node info */
+	this->info_all = SPA_NODE_CHANGE_MASK_FLAGS |
+		SPA_NODE_CHANGE_MASK_PROPS |
+		SPA_NODE_CHANGE_MASK_PARAMS;
+	this->info = SPA_NODE_INFO_INIT();
+	this->info.max_input_ports = 1;
+	this->info.max_output_ports = 1;
+	this->info.flags = SPA_NODE_FLAG_RT;
+	this->params[IDX_PropInfo] = SPA_PARAM_INFO(SPA_PARAM_PropInfo, SPA_PARAM_INFO_READ);
+	this->params[IDX_Props] = SPA_PARAM_INFO(SPA_PARAM_Props, SPA_PARAM_INFO_READWRITE);
+	this->params[IDX_NODE_IO] = SPA_PARAM_INFO(SPA_PARAM_IO, SPA_PARAM_INFO_READ);
+	this->info.params = this->params;
+	this->info.n_params = N_NODE_PARAMS;
+
+	/* set the port info */
+	for (i = 0; i < N_PORTS; ++i) {
+		struct port *port = &this->ports[i];
+		static const struct spa_dict_item in_port_items[] = {
+			SPA_DICT_ITEM_INIT(SPA_KEY_FORMAT_DSP, "8 bit raw midi"),
+			SPA_DICT_ITEM_INIT(SPA_KEY_PORT_NAME, "in"),
+			SPA_DICT_ITEM_INIT(SPA_KEY_PORT_ALIAS, "in"),
+		};
+		static const struct spa_dict_item out_port_items[] = {
+			SPA_DICT_ITEM_INIT(SPA_KEY_FORMAT_DSP, "8 bit raw midi"),
+			SPA_DICT_ITEM_INIT(SPA_KEY_PORT_NAME, "out"),
+			SPA_DICT_ITEM_INIT(SPA_KEY_PORT_ALIAS, "out"),
+		};
+		static const struct spa_dict in_port_props = SPA_DICT_INIT_ARRAY(in_port_items);
+		static const struct spa_dict out_port_props = SPA_DICT_INIT_ARRAY(out_port_items);
+
+		spa_zero(*port);
+
+		port->impl = this;
+
+		port->id = 0;
+		port->direction = (i == PORT_OUT) ? SPA_DIRECTION_OUTPUT :
+			SPA_DIRECTION_INPUT;
+
+		port->info_all = SPA_PORT_CHANGE_MASK_FLAGS |
+			SPA_PORT_CHANGE_MASK_PROPS |
+			SPA_PORT_CHANGE_MASK_PARAMS;
+		port->info = SPA_PORT_INFO_INIT();
+		port->info.change_mask = SPA_PORT_CHANGE_MASK_FLAGS;
+		port->info.flags = SPA_PORT_FLAG_LIVE;
+		port->params[IDX_EnumFormat] = SPA_PARAM_INFO(SPA_PARAM_EnumFormat, SPA_PARAM_INFO_READ);
+		port->params[IDX_Meta] = SPA_PARAM_INFO(SPA_PARAM_Meta, SPA_PARAM_INFO_READ);
+		port->params[IDX_IO] = SPA_PARAM_INFO(SPA_PARAM_IO, SPA_PARAM_INFO_READ);
+		port->params[IDX_Format] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
+		port->params[IDX_Buffers] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
+		port->params[IDX_Latency] = SPA_PARAM_INFO(SPA_PARAM_Latency, SPA_PARAM_INFO_READWRITE);
+		port->info.params = port->params;
+		port->info.n_params = N_PORT_PARAMS;
+		port->info.props = (i == PORT_OUT) ? &out_port_props : &in_port_props;
+
+		port->latency = SPA_LATENCY_INFO(port->direction);
+		port->latency.min_quantum = 1.0f;
+		port->latency.max_quantum = 1.0f;
+
+		/* Init the buffer lists */
+		spa_list_init(&port->ready);
+		spa_list_init(&port->free);
+	}
+
+	this->duration = 1024;
+	this->rate = 48000;
+
+	set_latency(this, false);
+
+	if (this->role == NODE_SERVER) {
+		this->server = spa_bt_midi_server_new(&impl_server, this->conn, this->log, this);
+		if (this->server == NULL)
+			goto fail;
+	} else {
+		this->proxy = bluez5_gatt_characteristic1_proxy_new_sync(this->conn,
+				G_DBUS_PROXY_FLAGS_DO_NOT_AUTO_START,
+				BLUEZ_SERVICE,
+				this->chr_path,
+				NULL,
+				&err);
+		if (this->proxy == NULL) {
+			spa_log_error(this->log,
+					"Failed to create BLE MIDI GATT proxy %s: %s",
+					this->chr_path, err->message);
+			g_error_free(err);
+			res = -EIO;
+			goto fail;
+		}
+	}
+
+	this->timerfd = spa_system_timerfd_create(this->data_system,
+			CLOCK_MONOTONIC, SPA_FD_CLOEXEC | SPA_FD_NONBLOCK);
+
+	return 0;
+
+fail:
+	res = (res < 0) ? res : ((errno > 0) ? -errno : -EIO);
+	impl_clear(handle);
+	return res;
+}
+
+static const struct spa_interface_info impl_interfaces[] = {
+	{SPA_TYPE_INTERFACE_Node,},
+};
+
+static int
+impl_enum_interface_info(const struct spa_handle_factory *factory,
+		const struct spa_interface_info **info, uint32_t *index)
+{
+	spa_return_val_if_fail(factory != NULL, -EINVAL);
+	spa_return_val_if_fail(info != NULL, -EINVAL);
+	spa_return_val_if_fail(index != NULL, -EINVAL);
+
+	switch (*index) {
+	case 0:
+		*info = &impl_interfaces[*index];
+		break;
+	default:
+		return 0;
+	}
+	(*index)++;
+	return 1;
+}
+
+static const struct spa_dict_item info_items[] = {
+	{ SPA_KEY_FACTORY_AUTHOR, "Pauli Virtanen <pav@iki.fi>" },
+	{ SPA_KEY_FACTORY_DESCRIPTION, "Bluez5 MIDI connection" },
+};
+
+static const struct spa_dict info = SPA_DICT_INIT_ARRAY(info_items);
+
+const struct spa_handle_factory spa_bluez5_midi_node_factory = {
+	SPA_VERSION_HANDLE_FACTORY,
+	SPA_NAME_API_BLUEZ5_MIDI_NODE,
+	&info,
+	impl_get_size,
+	impl_init,
+	impl_enum_interface_info,
+};