Adding upstream version 0.3.65.upstream/0.3.65upstream

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

1 files changed, 737 insertions, 0 deletions

diff --git a/src/modules/module-loopback.c b/src/modules/module-loopback.c
new file mode 100644
index 0000000..7d66539
--- /dev/null
+++ b/src/modules/module-loopback.c
@@ -0,0 +1,737 @@
+/* PipeWire
+ *
+ * Copyright © 2021 Wim Taymans
+ *
+ * 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 <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "config.h"
+
+#include <spa/utils/result.h>
+#include <spa/utils/string.h>
+#include <spa/utils/json.h>
+#include <spa/utils/ringbuffer.h>
+#include <spa/param/latency-utils.h>
+#include <spa/debug/types.h>
+
+#include <pipewire/impl.h>
+#include <pipewire/extensions/profiler.h>
+
+/** \page page_module_loopback PipeWire Module: Loopback
+ *
+ * The loopback module passes the output of a capture stream unmodified to a playback stream.
+ * It can be used to construct a link between a source and sink but also to
+ * create new virtual sinks or sources or to remap channel between streams.
+ *
+ * Because both ends of the loopback are built with streams, the session manager can
+ * manage the configuration and connection with the sinks and sources.
+ *
+ * ## Module Options
+ *
+ * - `node.description`: a human readable name for the loopback streams
+ * - `target.delay.sec`: delay in seconds as float (Since 0.3.60)
+ * - `capture.props = {}`: properties to be passed to the input stream
+ * - `playback.props = {}`: properties to be passed to the output stream
+ *
+ * ## General options
+ *
+ * Options with well-known behavior. Most options can be added to the global
+ * configuration or the individual streams:
+ *
+ * - \ref PW_KEY_REMOTE_NAME
+ * - \ref PW_KEY_AUDIO_RATE
+ * - \ref PW_KEY_AUDIO_CHANNELS
+ * - \ref SPA_KEY_AUDIO_POSITION
+ * - \ref PW_KEY_MEDIA_NAME
+ * - \ref PW_KEY_NODE_LATENCY
+ * - \ref PW_KEY_NODE_DESCRIPTION
+ * - \ref PW_KEY_NODE_GROUP
+ * - \ref PW_KEY_NODE_LINK_GROUP
+ * - \ref PW_KEY_NODE_VIRTUAL
+ * - \ref PW_KEY_NODE_NAME: See notes below. If not specified, defaults to
+ *   	'loopback-<pid>-<module-id>'.
+ *
+ * Stream only properties:
+ *
+ * - \ref PW_KEY_MEDIA_CLASS
+ * - \ref PW_KEY_NODE_NAME:  if not given per stream, the global node.name will be
+ *         prefixed with 'input.' and 'output.' to generate a capture and playback
+ *         stream node.name respectively.
+ *
+ * ## Example configuration of a virtual sink
+ *
+ * This Virtual sink routes stereo input to the rear channels of a 7.1 sink.
+ *
+ *\code{.unparsed}
+ * context.modules = [
+ * {   name = libpipewire-module-loopback
+ *     args = {
+ *         node.description = "CM106 Stereo Pair 2"
+ *         #target.delay.sec = 1.5
+ *         capture.props = {
+ *             node.name = "CM106_stereo_pair_2"
+ *             media.class = "Audio/Sink"
+ *             audio.position = [ FL FR ]
+ *         }
+ *         playback.props = {
+ *             node.name = "playback.CM106_stereo_pair_2"
+ *             audio.position = [ RL RR ]
+ *             target.object = "alsa_output.usb-0d8c_USB_Sound_Device-00.analog-surround-71"
+ *             node.dont-reconnect = true
+ *             stream.dont-remix = true
+ *             node.passive = true
+ *         }
+ *     }
+ * }
+ * ]
+ *\endcode
+ *
+ * ## See also
+ *
+ * `pw-loopback` : a tool that loads the loopback module with given parameters.
+ */
+
+#define NAME "loopback"
+
+PW_LOG_TOPIC_STATIC(mod_topic, "mod." NAME);
+#define PW_LOG_TOPIC_DEFAULT mod_topic
+
+static const struct spa_dict_item module_props[] = {
+	{ PW_KEY_MODULE_AUTHOR, "Wim Taymans <wim.taymans@gmail.com>" },
+	{ PW_KEY_MODULE_DESCRIPTION, "Create loopback streams" },
+	{ PW_KEY_MODULE_USAGE, " [ remote.name=<remote> ] "
+				"[ node.latency=<latency as fraction> ] "
+				"[ node.description=<description of the nodes> ] "
+				"[ audio.rate=<sample rate> ] "
+				"[ audio.channels=<number of channels> ] "
+				"[ audio.position=<channel map> ] "
+				"[ target.delay.sec=<delay as seconds in float> ] "
+				"[ capture.props=<properties> ] "
+				"[ playback.props=<properties> ] " },
+	{ PW_KEY_MODULE_VERSION, PACKAGE_VERSION },
+};
+
+#include <stdlib.h>
+#include <signal.h>
+#include <getopt.h>
+#include <limits.h>
+#include <math.h>
+
+#include <spa/pod/builder.h>
+#include <spa/param/audio/format-utils.h>
+#include <spa/param/audio/raw.h>
+
+#include <pipewire/pipewire.h>
+
+struct impl {
+	struct pw_context *context;
+
+	struct pw_impl_module *module;
+
+	struct spa_hook module_listener;
+
+	struct pw_core *core;
+	struct spa_hook core_proxy_listener;
+	struct spa_hook core_listener;
+
+	struct pw_properties *capture_props;
+	struct pw_stream *capture;
+	struct spa_hook capture_listener;
+	struct spa_audio_info_raw capture_info;
+	struct spa_latency_info capture_latency;
+
+	struct pw_properties *playback_props;
+	struct pw_stream *playback;
+	struct spa_hook playback_listener;
+	struct spa_audio_info_raw playback_info;
+	struct spa_latency_info playback_latency;
+
+	unsigned int do_disconnect:1;
+	unsigned int recalc_delay:1;
+
+	float target_delay;
+	struct spa_ringbuffer buffer;
+	uint8_t *buffer_data;
+	uint32_t buffer_size;
+};
+
+static void capture_destroy(void *d)
+{
+	struct impl *impl = d;
+	spa_hook_remove(&impl->capture_listener);
+	impl->capture = NULL;
+}
+
+static void recalculate_delay(struct impl *impl)
+{
+	uint32_t target = impl->capture_info.rate * impl->target_delay, cdelay, pdelay;
+	uint32_t delay, w;
+	struct pw_time pwt;
+
+	pw_stream_get_time_n(impl->playback, &pwt, sizeof(pwt));
+	pdelay = pwt.delay;
+	pw_stream_get_time_n(impl->capture, &pwt, sizeof(pwt));
+	cdelay = pwt.delay;
+
+	delay = target - SPA_MIN(target, pdelay + cdelay);
+	delay = SPA_MIN(delay, impl->buffer_size / 4);
+
+	spa_ringbuffer_get_write_index(&impl->buffer, &w);
+	spa_ringbuffer_read_update(&impl->buffer, w - (delay * 4));
+
+	pw_log_info("target:%d c:%d + p:%d + delay:%d = (%d)",
+			target, cdelay, pdelay, delay,
+			cdelay + pdelay + delay);
+}
+
+static void capture_process(void *d)
+{
+	struct impl *impl = d;
+	pw_stream_trigger_process(impl->playback);
+}
+
+static void playback_process(void *d)
+{
+	struct impl *impl = d;
+	struct pw_buffer *in, *out;
+	uint32_t i;
+
+	if (impl->recalc_delay) {
+		recalculate_delay(impl);
+		impl->recalc_delay = false;
+	}
+
+	if ((in = pw_stream_dequeue_buffer(impl->capture)) == NULL)
+		pw_log_debug("out of capture buffers: %m");
+
+	if ((out = pw_stream_dequeue_buffer(impl->playback)) == NULL)
+		pw_log_debug("out of playback buffers: %m");
+
+	if (in != NULL && out != NULL) {
+		uint32_t outsize = UINT32_MAX;
+		int32_t stride = 0;
+		struct spa_data *d;
+		const void *src[in->buffer->n_datas];
+		uint32_t r, w, buffer_size;
+
+		for (i = 0; i < in->buffer->n_datas; i++) {
+			uint32_t offs, size;
+
+			d = &in->buffer->datas[i];
+			offs = SPA_MIN(d->chunk->offset, d->maxsize);
+			size = SPA_MIN(d->chunk->size, d->maxsize - offs);
+
+			src[i] = SPA_PTROFF(d->data, offs, void);
+			outsize = SPA_MIN(outsize, size);
+			stride = SPA_MAX(stride, d->chunk->stride);
+		}
+		if (impl->buffer_size > 0) {
+			buffer_size = impl->buffer_size;
+			spa_ringbuffer_get_write_index(&impl->buffer, &w);
+			for (i = 0; i < in->buffer->n_datas; i++) {
+				void *buffer_data = &impl->buffer_data[i * buffer_size];
+				spa_ringbuffer_write_data(&impl->buffer,
+						buffer_data, buffer_size,
+						w % buffer_size, src[i], outsize);
+				src[i] = buffer_data;
+			}
+			w += outsize;
+			spa_ringbuffer_write_update(&impl->buffer, w);
+			spa_ringbuffer_get_read_index(&impl->buffer, &r);
+		} else {
+			r = 0;
+			buffer_size = outsize;
+		}
+		for (i = 0; i < out->buffer->n_datas; i++) {
+			d = &out->buffer->datas[i];
+
+			outsize = SPA_MIN(outsize, d->maxsize);
+
+			if (i < in->buffer->n_datas)
+				spa_ringbuffer_read_data(&impl->buffer,
+						src[i], buffer_size,
+						r % buffer_size,
+						d->data, outsize);
+			else
+				memset(d->data, 0, outsize);
+
+			d->chunk->offset = 0;
+			d->chunk->size = outsize;
+			d->chunk->stride = stride;
+		}
+		if (impl->buffer_size > 0) {
+			r += outsize;
+			spa_ringbuffer_read_update(&impl->buffer, r);
+		}
+	}
+
+	if (in != NULL)
+		pw_stream_queue_buffer(impl->capture, in);
+	if (out != NULL)
+		pw_stream_queue_buffer(impl->playback, out);
+}
+
+static void param_latency_changed(struct impl *impl, const struct spa_pod *param,
+		struct spa_latency_info *info, struct pw_stream *other)
+{
+	struct spa_latency_info latency;
+	uint8_t buffer[1024];
+	struct spa_pod_builder b;
+	const struct spa_pod *params[1];
+
+	if (spa_latency_parse(param, &latency) < 0)
+		return;
+
+	*info = latency;
+
+	spa_pod_builder_init(&b, buffer, sizeof(buffer));
+	params[0] = spa_latency_build(&b, SPA_PARAM_Latency, &latency);
+	pw_stream_update_params(other, params, 1);
+
+	impl->recalc_delay = true;
+}
+
+static void stream_state_changed(void *data, enum pw_stream_state old,
+		enum pw_stream_state state, const char *error)
+{
+	struct impl *impl = data;
+	switch (state) {
+	case PW_STREAM_STATE_PAUSED:
+		pw_stream_flush(impl->playback, false);
+		pw_stream_flush(impl->capture, false);
+		impl->recalc_delay = true;
+		break;
+	case PW_STREAM_STATE_UNCONNECTED:
+		pw_log_info("module %p: unconnected", impl);
+		pw_impl_module_schedule_destroy(impl->module);
+		break;
+	case PW_STREAM_STATE_ERROR:
+		pw_log_info("module %p: error: %s", impl, error);
+		break;
+	default:
+		break;
+	}
+}
+
+static void recalculate_buffer(struct impl *impl)
+{
+	if (impl->target_delay > 0.0f) {
+		uint32_t delay = impl->capture_info.rate * impl->target_delay;
+		void *data;
+
+		impl->buffer_size = (delay + (1u<<15)) * 4;
+		data = realloc(impl->buffer_data, impl->buffer_size * impl->capture_info.channels);
+		if (data == NULL) {
+			pw_log_warn("can't allocate delay buffer, delay disabled: %m");
+			impl->buffer_size = 0;
+			free(impl->buffer_data);
+		}
+		impl->buffer_data = data;
+		spa_ringbuffer_init(&impl->buffer);
+	} else {
+		impl->buffer_size = 0;
+		free(impl->buffer_data);
+		impl->buffer_data = NULL;
+	}
+	pw_log_info("configured delay:%f buffer:%d", impl->target_delay, impl->buffer_size);
+	impl->recalc_delay = true;
+}
+
+static void capture_param_changed(void *data, uint32_t id, const struct spa_pod *param)
+{
+	struct impl *impl = data;
+
+	switch (id) {
+	case SPA_PARAM_Format:
+	{
+		struct spa_audio_info_raw info;
+		if (param == NULL)
+			return;
+		if (spa_format_audio_raw_parse(param, &info) < 0)
+			return;
+		if (info.rate == 0 ||
+		    info.channels == 0 ||
+		    info.channels > SPA_AUDIO_MAX_CHANNELS)
+			return;
+
+		impl->capture_info = info;
+		recalculate_buffer(impl);
+		break;
+	}
+	case SPA_PARAM_Latency:
+		param_latency_changed(impl, param, &impl->capture_latency, impl->playback);
+		break;
+	}
+}
+
+static const struct pw_stream_events in_stream_events = {
+	PW_VERSION_STREAM_EVENTS,
+	.destroy = capture_destroy,
+	.process = capture_process,
+	.state_changed = stream_state_changed,
+	.param_changed = capture_param_changed,
+};
+
+static void playback_destroy(void *d)
+{
+	struct impl *impl = d;
+	spa_hook_remove(&impl->playback_listener);
+	impl->playback = NULL;
+}
+
+static void playback_param_changed(void *data, uint32_t id, const struct spa_pod *param)
+{
+	struct impl *impl = data;
+
+	switch (id) {
+	case SPA_PARAM_Latency:
+		param_latency_changed(impl, param, &impl->playback_latency, impl->capture);
+		break;
+	}
+}
+static const struct pw_stream_events out_stream_events = {
+	PW_VERSION_STREAM_EVENTS,
+	.destroy = playback_destroy,
+	.process = playback_process,
+	.state_changed = stream_state_changed,
+	.param_changed = playback_param_changed,
+};
+
+static int setup_streams(struct impl *impl)
+{
+	int res;
+	uint32_t n_params;
+	const struct spa_pod *params[1];
+	uint8_t buffer[1024];
+	struct spa_pod_builder b;
+
+	impl->capture = pw_stream_new(impl->core,
+			"loopback capture", impl->capture_props);
+	impl->capture_props = NULL;
+	if (impl->capture == NULL)
+		return -errno;
+
+	pw_stream_add_listener(impl->capture,
+			&impl->capture_listener,
+			&in_stream_events, impl);
+
+	impl->playback = pw_stream_new(impl->core,
+			"loopback playback", impl->playback_props);
+	impl->playback_props = NULL;
+	if (impl->playback == NULL)
+		return -errno;
+
+	pw_stream_add_listener(impl->playback,
+			&impl->playback_listener,
+			&out_stream_events, impl);
+
+	/* connect playback first to activate it before capture triggers it */
+	n_params = 0;
+	spa_pod_builder_init(&b, buffer, sizeof(buffer));
+	params[n_params++] = spa_format_audio_raw_build(&b, SPA_PARAM_EnumFormat,
+			&impl->playback_info);
+	if ((res = pw_stream_connect(impl->playback,
+			PW_DIRECTION_OUTPUT,
+			PW_ID_ANY,
+			PW_STREAM_FLAG_AUTOCONNECT |
+			PW_STREAM_FLAG_MAP_BUFFERS |
+			PW_STREAM_FLAG_RT_PROCESS |
+			PW_STREAM_FLAG_TRIGGER,
+			params, n_params)) < 0)
+		return res;
+
+	n_params = 0;
+	spa_pod_builder_init(&b, buffer, sizeof(buffer));
+	params[n_params++] = spa_format_audio_raw_build(&b, SPA_PARAM_EnumFormat,
+			&impl->capture_info);
+	if ((res = pw_stream_connect(impl->capture,
+			PW_DIRECTION_INPUT,
+			PW_ID_ANY,
+			PW_STREAM_FLAG_AUTOCONNECT |
+			PW_STREAM_FLAG_MAP_BUFFERS |
+			PW_STREAM_FLAG_RT_PROCESS,
+			params, n_params)) < 0)
+		return res;
+
+	return 0;
+}
+
+static void core_error(void *data, uint32_t id, int seq, int res, const char *message)
+{
+	struct impl *impl = data;
+
+	if (res == -ENOENT) {
+		pw_log_info("message id:%u seq:%d res:%d (%s): %s",
+				id, seq, res, spa_strerror(res), message);
+	} else {
+		pw_log_warn("error id:%u seq:%d res:%d (%s): %s",
+				id, seq, res, spa_strerror(res), message);
+	}
+
+	if (id == PW_ID_CORE && res == -EPIPE)
+		pw_impl_module_schedule_destroy(impl->module);
+}
+
+static const struct pw_core_events core_events = {
+	PW_VERSION_CORE_EVENTS,
+	.error = core_error,
+};
+
+static void core_destroy(void *d)
+{
+	struct impl *impl = d;
+	spa_hook_remove(&impl->core_listener);
+	impl->core = NULL;
+	pw_impl_module_schedule_destroy(impl->module);
+}
+
+static const struct pw_proxy_events core_proxy_events = {
+	.destroy = core_destroy,
+};
+
+static void impl_destroy(struct impl *impl)
+{
+	/* deactivate both streams before destroying any of them */
+	if (impl->capture)
+		pw_stream_set_active(impl->capture, false);
+	if (impl->playback)
+		pw_stream_set_active(impl->playback, false);
+
+	if (impl->capture)
+		pw_stream_destroy(impl->capture);
+	if (impl->playback)
+		pw_stream_destroy(impl->playback);
+
+	if (impl->core && impl->do_disconnect)
+		pw_core_disconnect(impl->core);
+
+	pw_properties_free(impl->capture_props);
+	pw_properties_free(impl->playback_props);
+	free(impl);
+}
+
+static void module_destroy(void *data)
+{
+	struct impl *impl = data;
+	spa_hook_remove(&impl->module_listener);
+	impl_destroy(impl);
+}
+
+static const struct pw_impl_module_events module_events = {
+	PW_VERSION_IMPL_MODULE_EVENTS,
+	.destroy = module_destroy,
+};
+
+static uint32_t channel_from_name(const char *name)
+{
+	int i;
+	for (i = 0; spa_type_audio_channel[i].name; i++) {
+		if (spa_streq(name, spa_debug_type_short_name(spa_type_audio_channel[i].name)))
+			return spa_type_audio_channel[i].type;
+	}
+	return SPA_AUDIO_CHANNEL_UNKNOWN;
+}
+
+static void parse_position(struct spa_audio_info_raw *info, const char *val, size_t len)
+{
+	struct spa_json it[2];
+	char v[256];
+
+	spa_json_init(&it[0], val, len);
+        if (spa_json_enter_array(&it[0], &it[1]) <= 0)
+                spa_json_init(&it[1], val, len);
+
+	info->channels = 0;
+	while (spa_json_get_string(&it[1], v, sizeof(v)) > 0 &&
+	    info->channels < SPA_AUDIO_MAX_CHANNELS) {
+		info->position[info->channels++] = channel_from_name(v);
+	}
+}
+
+static void parse_audio_info(struct pw_properties *props, struct spa_audio_info_raw *info)
+{
+	const char *str;
+
+	*info = SPA_AUDIO_INFO_RAW_INIT(
+			.format = SPA_AUDIO_FORMAT_F32P);
+	info->rate = pw_properties_get_int32(props, PW_KEY_AUDIO_RATE, 0);
+	info->channels = pw_properties_get_uint32(props, PW_KEY_AUDIO_CHANNELS, 0);
+	info->channels = SPA_MIN(info->channels, SPA_AUDIO_MAX_CHANNELS);
+	if ((str = pw_properties_get(props, SPA_KEY_AUDIO_POSITION)) != NULL)
+		parse_position(info, str, strlen(str));
+}
+
+static void copy_props(struct impl *impl, struct pw_properties *props, const char *key)
+{
+	const char *str;
+	if ((str = pw_properties_get(props, key)) != NULL) {
+		if (pw_properties_get(impl->capture_props, key) == NULL)
+			pw_properties_set(impl->capture_props, key, str);
+		if (pw_properties_get(impl->playback_props, key) == NULL)
+			pw_properties_set(impl->playback_props, key, str);
+	}
+}
+
+SPA_EXPORT
+int pipewire__module_init(struct pw_impl_module *module, const char *args)
+{
+	struct pw_context *context = pw_impl_module_get_context(module);
+	struct pw_properties *props;
+	struct impl *impl;
+	uint32_t id = pw_global_get_id(pw_impl_module_get_global(module));
+	uint32_t pid = getpid();
+	const char *str;
+	int res;
+
+	PW_LOG_TOPIC_INIT(mod_topic);
+
+	impl = calloc(1, sizeof(struct impl));
+	if (impl == NULL)
+		return -errno;
+
+	pw_log_debug("module %p: new %s", impl, args);
+
+	if (args)
+		props = pw_properties_new_string(args);
+	else
+		props = pw_properties_new(NULL, NULL);
+	if (props == NULL) {
+		res = -errno;
+		pw_log_error( "can't create properties: %m");
+		goto error;
+	}
+
+	impl->capture_props = pw_properties_new(NULL, NULL);
+	impl->playback_props = pw_properties_new(NULL, NULL);
+	if (impl->capture_props == NULL || impl->playback_props == NULL) {
+		res = -errno;
+		pw_log_error( "can't create properties: %m");
+		goto error;
+	}
+
+	impl->module = module;
+	impl->context = context;
+
+	if (pw_properties_get(props, PW_KEY_NODE_GROUP) == NULL)
+		pw_properties_setf(props, PW_KEY_NODE_GROUP, "loopback-%u-%u", pid, id);
+	if (pw_properties_get(props, PW_KEY_NODE_LINK_GROUP) == NULL)
+		pw_properties_setf(props, PW_KEY_NODE_LINK_GROUP, "loopback-%u-%u", pid, id);
+	if (pw_properties_get(props, PW_KEY_NODE_VIRTUAL) == NULL)
+		pw_properties_set(props, PW_KEY_NODE_VIRTUAL, "true");
+	if (pw_properties_get(props, "resample.prefill") == NULL)
+		pw_properties_set(props, "resample.prefill", "true");
+
+	if ((str = pw_properties_get(props, "capture.props")) != NULL)
+		pw_properties_update_string(impl->capture_props, str, strlen(str));
+	if ((str = pw_properties_get(props, "playback.props")) != NULL)
+		pw_properties_update_string(impl->playback_props, str, strlen(str));
+
+	if ((str = pw_properties_get(props, "target.delay.sec")) != NULL)
+		spa_atof(str, &impl->target_delay);
+	if (impl->target_delay > 0.0f &&
+	    pw_properties_get(props, PW_KEY_NODE_LATENCY) == NULL)
+		/* a source and sink (USB) usually have a 1.5 quantum delay, so we use
+		 * a 2 times smaller quantum to compensate */
+		pw_properties_setf(props, PW_KEY_NODE_LATENCY, "%u/%u",
+				(unsigned)(impl->target_delay * 48000 / 3), 48000);
+
+	copy_props(impl, props, PW_KEY_AUDIO_RATE);
+	copy_props(impl, props, PW_KEY_AUDIO_CHANNELS);
+	copy_props(impl, props, SPA_KEY_AUDIO_POSITION);
+	copy_props(impl, props, PW_KEY_NODE_DESCRIPTION);
+	copy_props(impl, props, PW_KEY_NODE_GROUP);
+	copy_props(impl, props, PW_KEY_NODE_LINK_GROUP);
+	copy_props(impl, props, PW_KEY_NODE_LATENCY);
+	copy_props(impl, props, PW_KEY_NODE_VIRTUAL);
+	copy_props(impl, props, PW_KEY_MEDIA_NAME);
+	copy_props(impl, props, "resample.prefill");
+
+	if ((str = pw_properties_get(props, PW_KEY_NODE_NAME)) == NULL) {
+		pw_properties_setf(props, PW_KEY_NODE_NAME,
+				"loopback-%u-%u", pid, id);
+		str = pw_properties_get(props, PW_KEY_NODE_NAME);
+	}
+	if (pw_properties_get(impl->capture_props, PW_KEY_NODE_NAME) == NULL)
+		pw_properties_setf(impl->capture_props, PW_KEY_NODE_NAME,
+				"input.%s", str);
+	if (pw_properties_get(impl->playback_props, PW_KEY_NODE_NAME) == NULL)
+		pw_properties_setf(impl->playback_props, PW_KEY_NODE_NAME,
+				"output.%s", str);
+	if (pw_properties_get(impl->capture_props, PW_KEY_NODE_DESCRIPTION) == NULL)
+		pw_properties_set(impl->capture_props, PW_KEY_NODE_DESCRIPTION, str);
+	if (pw_properties_get(impl->playback_props, PW_KEY_NODE_DESCRIPTION) == NULL)
+		pw_properties_set(impl->playback_props, PW_KEY_NODE_DESCRIPTION, str);
+
+	parse_audio_info(impl->capture_props, &impl->capture_info);
+	parse_audio_info(impl->playback_props, &impl->playback_info);
+
+	if (pw_properties_get(impl->capture_props, PW_KEY_MEDIA_NAME) == NULL)
+		pw_properties_setf(impl->capture_props, PW_KEY_MEDIA_NAME, "%s input",
+				pw_properties_get(impl->capture_props, PW_KEY_NODE_DESCRIPTION));
+	if (pw_properties_get(impl->playback_props, PW_KEY_MEDIA_NAME) == NULL)
+		pw_properties_setf(impl->playback_props, PW_KEY_MEDIA_NAME, "%s output",
+				pw_properties_get(impl->playback_props, PW_KEY_NODE_DESCRIPTION));
+
+	impl->core = pw_context_get_object(impl->context, PW_TYPE_INTERFACE_Core);
+	if (impl->core == NULL) {
+		str = pw_properties_get(props, PW_KEY_REMOTE_NAME);
+		impl->core = pw_context_connect(impl->context,
+				pw_properties_new(
+					PW_KEY_REMOTE_NAME, str,
+					NULL),
+				0);
+		impl->do_disconnect = true;
+	}
+	if (impl->core == NULL) {
+		res = -errno;
+		pw_log_error("can't connect: %m");
+		goto error;
+	}
+
+	pw_properties_free(props);
+
+	pw_proxy_add_listener((struct pw_proxy*)impl->core,
+			&impl->core_proxy_listener,
+			&core_proxy_events, impl);
+	pw_core_add_listener(impl->core,
+			&impl->core_listener,
+			&core_events, impl);
+
+	setup_streams(impl);
+
+	pw_impl_module_add_listener(module, &impl->module_listener, &module_events, impl);
+
+	pw_impl_module_update_properties(module, &SPA_DICT_INIT_ARRAY(module_props));
+
+	return 0;
+
+error:
+	pw_properties_free(props);
+	impl_destroy(impl);
+	return res;
+}