diff --git a/src/modules/module-media-session/floatmix.c b/src/modules/module-media-session/floatmix.c
new file mode 100644
index 000000000..dc0b91de1
--- /dev/null
+++ b/src/modules/module-media-session/floatmix.c
@@ -0,0 +1,1083 @@
+/* Spa
+ * Copyright (C) 2018 Wim Taymans <wim.taymans@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+
+#include <spa/support/log.h>
+#include <spa/support/type-map.h>
+#include <spa/utils/list.h>
+#include <spa/node/node.h>
+#include <spa/node/io.h>
+#include <spa/param/audio/format-utils.h>
+#include <spa/param/buffers.h>
+#include <spa/param/meta.h>
+#include <spa/param/io.h>
+
+#include <spa/lib/pod.h>
+
+#define NAME "floatmix"
+
+#define MAX_BUFFERS     64
+#define MAX_PORTS       128
+#define MAX_SAMPLES     1024
+
+#define PORT_DEFAULT_VOLUME	1.0
+#define PORT_DEFAULT_MUTE	false
+
+struct port_props {
+	double volume;
+	int32_t mute;
+};
+
+static void port_props_reset(struct port_props *props)
+{
+	props->volume = PORT_DEFAULT_VOLUME;
+	props->mute = PORT_DEFAULT_MUTE;
+}
+
+struct buffer {
+	struct spa_list link;
+#define BUFFER_FLAG_QUEUED	(1 << 0)
+	uint32_t flags;
+
+	struct spa_buffer *buffer;
+	struct spa_meta_header *h;
+
+	uint32_t id;
+	struct spa_buffer buf;
+        struct spa_data datas[1];
+        struct spa_chunk chunk[1];
+};
+
+struct port {
+	bool valid;
+	uint32_t id;
+
+	struct port_props props;
+
+	struct spa_io_buffers *io;
+	struct spa_io_control_range *ctrl;
+	double *io_volume;
+	int32_t *io_mute;
+
+	struct spa_port_info info;
+
+	bool have_format;
+
+	struct buffer buffers[MAX_BUFFERS];
+	uint32_t n_buffers;
+
+	struct spa_list queue;
+	size_t queued_bytes;
+};
+
+struct type {
+	uint32_t node;
+	uint32_t format;
+	uint32_t prop_volume;
+	uint32_t prop_mute;
+	uint32_t io_prop_volume;
+	uint32_t io_prop_mute;
+	struct spa_type_io io;
+	struct spa_type_param param;
+	struct spa_type_media_type media_type;
+	struct spa_type_media_subtype media_subtype;
+	struct spa_type_format_audio format_audio;
+	struct spa_type_audio_format audio_format;
+	struct spa_type_command_node command_node;
+	struct spa_type_meta meta;
+	struct spa_type_data data;
+	struct spa_type_param_buffers param_buffers;
+	struct spa_type_param_meta param_meta;
+	struct spa_type_param_io param_io;
+};
+
+static inline void init_type(struct type *type, struct spa_type_map *map)
+{
+	type->node = spa_type_map_get_id(map, SPA_TYPE__Node);
+	type->format = spa_type_map_get_id(map, SPA_TYPE__Format);
+	type->prop_volume = spa_type_map_get_id(map, SPA_TYPE_PROPS__volume);
+	type->prop_mute = spa_type_map_get_id(map, SPA_TYPE_PROPS__mute);
+	type->io_prop_volume = spa_type_map_get_id(map, SPA_TYPE_IO_PROP_BASE "volume");
+	type->io_prop_mute = spa_type_map_get_id(map, SPA_TYPE_IO_PROP_BASE "mute");
+	spa_type_io_map(map, &type->io);
+	spa_type_param_map(map, &type->param);
+	spa_type_media_type_map(map, &type->media_type);
+	spa_type_media_subtype_map(map, &type->media_subtype);
+	spa_type_format_audio_map(map, &type->format_audio);
+	spa_type_audio_format_map(map, &type->audio_format);
+	spa_type_command_node_map(map, &type->command_node);
+	spa_type_meta_map(map, &type->meta);
+	spa_type_data_map(map, &type->data);
+	spa_type_param_buffers_map(map, &type->param_buffers);
+	spa_type_param_meta_map(map, &type->param_meta);
+	spa_type_param_io_map(map, &type->param_io);
+}
+
+struct impl {
+	struct spa_handle handle;
+	struct spa_node node;
+
+	struct type type;
+	struct spa_type_map *map;
+	struct spa_log *log;
+
+	const struct spa_node_callbacks *callbacks;
+	void *user_data;
+
+	int port_count;
+	int last_port;
+	struct port in_ports[MAX_PORTS];
+	struct port out_ports[1];
+
+	bool have_format;
+	int n_formats;
+	struct spa_audio_info format;
+	uint32_t stride;
+
+	bool started;
+        float empty[MAX_SAMPLES];
+};
+
+#define CHECK_FREE_IN_PORT(this,d,p) ((d) == SPA_DIRECTION_INPUT && (p) < MAX_PORTS && !this->in_ports[(p)].valid)
+#define CHECK_IN_PORT(this,d,p)      ((d) == SPA_DIRECTION_INPUT && (p) < MAX_PORTS && this->in_ports[(p)].valid)
+#define CHECK_OUT_PORT(this,d,p)     ((d) == SPA_DIRECTION_OUTPUT && (p) == 0)
+#define CHECK_PORT(this,d,p)         (CHECK_OUT_PORT(this,d,p) || CHECK_IN_PORT (this,d,p))
+#define GET_IN_PORT(this,p)          (&this->in_ports[p])
+#define GET_OUT_PORT(this,p)         (&this->out_ports[p])
+#define GET_PORT(this,d,p)           (d == SPA_DIRECTION_INPUT ? GET_IN_PORT(this,p) : GET_OUT_PORT(this,p))
+
+static int impl_node_enum_params(struct spa_node *node,
+				 uint32_t id, uint32_t *index,
+				 const struct spa_pod *filter,
+				 struct spa_pod **param,
+				 struct spa_pod_builder *builder)
+{
+	return -ENOTSUP;
+}
+
+static int impl_node_set_param(struct spa_node *node, uint32_t id, uint32_t flags,
+			       const struct spa_pod *param)
+{
+	return -ENOTSUP;
+}
+
+static int impl_node_send_command(struct spa_node *node, const struct spa_command *command)
+{
+	struct impl *this;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+	spa_return_val_if_fail(command != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+
+	if (SPA_COMMAND_TYPE(command) == this->type.command_node.Start) {
+		this->started = true;
+	} else if (SPA_COMMAND_TYPE(command) == this->type.command_node.Pause) {
+		this->started = false;
+	} else
+		return -ENOTSUP;
+
+	return 0;
+}
+
+static int
+impl_node_set_callbacks(struct spa_node *node,
+			const struct spa_node_callbacks *callbacks,
+			void *user_data)
+{
+	struct impl *this;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+
+	this->callbacks = callbacks;
+	this->user_data = user_data;
+
+	return 0;
+}
+
+static int
+impl_node_get_n_ports(struct spa_node *node,
+		      uint32_t *n_input_ports,
+		      uint32_t *max_input_ports,
+		      uint32_t *n_output_ports,
+		      uint32_t *max_output_ports)
+{
+	struct impl *this;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+
+	if (n_input_ports)
+		*n_input_ports = this->port_count;
+	if (max_input_ports)
+		*max_input_ports = MAX_PORTS;
+	if (n_output_ports)
+		*n_output_ports = 1;
+	if (max_output_ports)
+		*max_output_ports = 1;
+
+	return 0;
+}
+
+static int
+impl_node_get_port_ids(struct spa_node *node,
+		       uint32_t *input_ids,
+		       uint32_t n_input_ids,
+		       uint32_t *output_ids,
+		       uint32_t n_output_ids)
+{
+	struct impl *this;
+	int i, idx;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+
+	if (input_ids) {
+		for (i = 0, idx = 0; i < this->last_port && idx < n_input_ids; i++) {
+			if (this->in_ports[i].valid)
+				input_ids[idx++] = i;
+		}
+	}
+	if (n_output_ids > 0 && output_ids)
+		output_ids[0] = 0;
+
+	return 0;
+}
+
+static int impl_node_add_port(struct spa_node *node, enum spa_direction direction, uint32_t port_id)
+{
+	struct impl *this;
+	struct port *port;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+
+	spa_return_val_if_fail(CHECK_FREE_IN_PORT(this, direction, port_id), -EINVAL);
+
+	port = GET_IN_PORT (this, port_id);
+	port->id = port_id;
+
+	port_props_reset(&port->props);
+	port->io_volume = &port->props.volume;
+	port->io_mute = &port->props.mute;
+
+	spa_list_init(&port->queue);
+	port->info.flags = SPA_PORT_INFO_FLAG_CAN_USE_BUFFERS |
+			   SPA_PORT_INFO_FLAG_REMOVABLE |
+			   SPA_PORT_INFO_FLAG_OPTIONAL |
+			   SPA_PORT_INFO_FLAG_IN_PLACE;
+
+	this->port_count++;
+	if (this->last_port <= port_id)
+		this->last_port = port_id + 1;
+	port->valid = true;
+
+	spa_log_info(this->log, NAME " %p: add port %d %d", this, port_id, this->last_port);
+
+	return 0;
+}
+
+static int
+impl_node_remove_port(struct spa_node *node, enum spa_direction direction, uint32_t port_id)
+{
+	struct impl *this;
+	struct port *port;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+
+	spa_return_val_if_fail(CHECK_IN_PORT(this, direction, port_id), -EINVAL);
+
+	port = GET_IN_PORT (this, port_id);
+
+	port->valid = false;
+	this->port_count--;
+	if (port->have_format && this->have_format) {
+		if (--this->n_formats == 0)
+			this->have_format = false;
+	}
+	spa_memzero(port, sizeof(struct port));
+
+	if (port_id == this->last_port - 1) {
+		int i;
+
+		for (i = this->last_port - 1; i >= 0; i--)
+			if (GET_IN_PORT (this, i)->valid)
+				break;
+
+		this->last_port = i + 1;
+	}
+	spa_log_info(this->log, NAME " %p: remove port %d %d", this, port_id, this->last_port);
+
+	return 0;
+}
+
+static int
+impl_node_port_get_info(struct spa_node *node,
+			enum spa_direction direction,
+			uint32_t port_id,
+			const struct spa_port_info **info)
+{
+	struct impl *this;
+	struct port *port;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+	spa_return_val_if_fail(info != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+
+	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
+
+	port = GET_PORT(this, direction, port_id);
+	*info = &port->info;
+
+	return 0;
+}
+
+static int port_enum_formats(struct spa_node *node,
+			     enum spa_direction direction, uint32_t port_id,
+			     uint32_t *index,
+			     struct spa_pod **param,
+			     struct spa_pod_builder *builder)
+{
+	struct impl *this = SPA_CONTAINER_OF(node, struct impl, node);
+	struct type *t = &this->type;
+
+	switch (*index) {
+	case 0:
+		if (this->have_format) {
+			*param = spa_pod_builder_object(builder,
+				t->param.idEnumFormat, t->format,
+				"I", t->media_type.audio,
+				"I", t->media_subtype.raw,
+				":", t->format_audio.format,   "I", this->format.info.raw.format,
+				":", t->format_audio.layout,   "i", this->format.info.raw.layout,
+				":", t->format_audio.rate,     "i", this->format.info.raw.rate,
+				":", t->format_audio.channels, "i", this->format.info.raw.channels);
+		} else {
+			*param = spa_pod_builder_object(builder,
+				t->param.idEnumFormat, t->format,
+				"I", t->media_type.audio,
+				"I", t->media_subtype.raw,
+				":", t->format_audio.format,   "I", t->audio_format.F32,
+				":", t->format_audio.layout,   "i", SPA_AUDIO_LAYOUT_NON_INTERLEAVED,
+				":", t->format_audio.rate,     "iru", 44100,
+					SPA_POD_PROP_MIN_MAX(1, INT32_MAX),
+				":", t->format_audio.channels, "iru", 1);
+		}
+		break;
+	default:
+		return 0;
+	}
+	return 1;
+}
+
+static int port_get_format(struct spa_node *node,
+			   enum spa_direction direction, uint32_t port_id,
+			   uint32_t *index,
+			   struct spa_pod **param,
+			   struct spa_pod_builder *builder)
+{
+	struct impl *this = SPA_CONTAINER_OF(node, struct impl, node);
+	struct type *t = &this->type;
+	struct port *port = GET_PORT(this, direction, port_id);
+
+	if (!port->have_format)
+		return -EIO;
+	if (*index > 0)
+		return 0;
+
+	*param = spa_pod_builder_object(builder,
+		t->param.idFormat, t->format,
+		"I", t->media_type.audio,
+		"I", t->media_subtype.raw,
+		":", t->format_audio.format,   "I", this->format.info.raw.format,
+		":", t->format_audio.layout,   "i", this->format.info.raw.layout,
+		":", t->format_audio.rate,     "i", this->format.info.raw.rate,
+		":", t->format_audio.channels, "i", this->format.info.raw.channels);
+
+	return 1;
+}
+
+static int
+impl_node_port_enum_params(struct spa_node *node,
+			   enum spa_direction direction, uint32_t port_id,
+			   uint32_t id, uint32_t *index,
+			   const struct spa_pod *filter,
+			   struct spa_pod **result,
+			   struct spa_pod_builder *builder)
+{
+	struct impl *this;
+	struct type *t;
+	struct port *port;
+	struct spa_pod *param;
+	struct spa_pod_builder b = { 0 };
+	uint8_t buffer[1024];
+	int res;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+	spa_return_val_if_fail(index != NULL, -EINVAL);
+	spa_return_val_if_fail(builder != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+	t = &this->type;
+
+	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
+
+	port = GET_PORT(this, direction, port_id);
+
+      next:
+	spa_pod_builder_init(&b, buffer, sizeof(buffer));
+
+	if (id == t->param.idList) {
+		uint32_t list[] = { t->param.idEnumFormat,
+				    t->param.idFormat,
+				    t->param.idBuffers,
+				    t->param.idMeta,
+				    t->param_io.idBuffers,
+				    t->param_io.idControl,
+				    t->param_io.idPropsIn };
+
+		if (*index < SPA_N_ELEMENTS(list))
+			param = spa_pod_builder_object(&b, id, t->param.List,
+				":", t->param.listId, "I", list[*index]);
+		else
+			return 0;
+	}
+	else if (id == t->param.idEnumFormat) {
+		if ((res = port_enum_formats(node, direction, port_id, index, &param, &b)) <= 0)
+			return res;
+	}
+	else if (id == t->param.idFormat) {
+		if ((res = port_get_format(node, direction, port_id, index, &param, &b)) <= 0)
+			return res;
+	}
+	else if (id == t->param.idBuffers) {
+		if (!port->have_format)
+			return -EIO;
+		if (*index > 0)
+			return 0;
+
+		param = spa_pod_builder_object(&b,
+			id, t->param_buffers.Buffers,
+			":", t->param_buffers.size,    "iru", 1024 * this->stride,
+				SPA_POD_PROP_MIN_MAX(16 * this->stride, INT32_MAX / this->stride),
+			":", t->param_buffers.stride,  "i", this->stride,
+			":", t->param_buffers.buffers, "iru", 1,
+				SPA_POD_PROP_MIN_MAX(1, MAX_BUFFERS),
+			":", t->param_buffers.align,   "i", 16);
+	}
+	else if (id == t->param.idMeta) {
+		if (!port->have_format)
+			return -EIO;
+
+		switch (*index) {
+		case 0:
+			param = spa_pod_builder_object(&b,
+				id, t->param_meta.Meta,
+				":", t->param_meta.type, "I", t->meta.Header,
+				":", t->param_meta.size, "i", sizeof(struct spa_meta_header));
+			break;
+		default:
+			return 0;
+		}
+	}
+	else if (id == t->param_io.idBuffers) {
+		switch (*index) {
+		case 0:
+			param = spa_pod_builder_object(&b,
+				id, t->param_io.Buffers,
+				":", t->param_io.id,   "I", t->io.Buffers,
+				":", t->param_io.size, "i", sizeof(struct spa_io_buffers));
+			break;
+		default:
+			return 0;
+		}
+	}
+	else if (id == t->param_io.idControl) {
+		switch (*index) {
+		case 0:
+			param = spa_pod_builder_object(&b,
+				id, t->param_io.Control,
+				":", t->param_io.id,   "I", t->io.ControlRange,
+				":", t->param_io.size, "i", sizeof(struct spa_io_control_range));
+			break;
+		default:
+			return 0;
+		}
+	}
+	else if (id == t->param_io.idPropsIn) {
+		struct port_props *p = &port->props;
+
+		if (direction == SPA_DIRECTION_OUTPUT)
+			return 0;
+
+		switch (*index) {
+		case 0:
+			param = spa_pod_builder_object(&b,
+				id, t->param_io.Prop,
+				":", t->param_io.id,    "I", t->io_prop_volume,
+				":", t->param_io.size,  "i", sizeof(struct spa_pod_double),
+				":", t->param.propId,   "I", t->prop_volume,
+				":", t->param.propType, "dru", p->volume,
+					SPA_POD_PROP_MIN_MAX(0.0, 10.0));
+			break;
+		case 1:
+			param = spa_pod_builder_object(&b,
+				id, t->param_io.Prop,
+				":", t->param_io.id,    "I", t->io_prop_mute,
+				":", t->param_io.size,  "i", sizeof(struct spa_pod_bool),
+				":", t->param.propId,   "I", t->prop_mute,
+				":", t->param.propType, "b", p->mute);
+			break;
+		default:
+			return 0;
+		}
+	}
+	else
+		return -ENOENT;
+
+	(*index)++;
+
+	if (spa_pod_filter(builder, result, param, filter) < 0)
+		goto next;
+
+	return 1;
+}
+
+static int clear_buffers(struct impl *this, struct port *port)
+{
+	if (port->n_buffers > 0) {
+		spa_log_info(this->log, NAME " %p: clear buffers %p", this, port);
+		port->n_buffers = 0;
+		spa_list_init(&port->queue);
+	}
+	return 0;
+}
+
+static int queue_buffer(struct impl *this, struct port *port, struct buffer *b)
+{
+	if (SPA_FLAG_CHECK(b->flags, BUFFER_FLAG_QUEUED))
+		return -EINVAL;
+
+	spa_list_append(&port->queue, &b->link);
+	SPA_FLAG_SET(b->flags, BUFFER_FLAG_QUEUED);
+	spa_log_trace(this->log, NAME " %p: queue buffer %d", this, b->buffer->id);
+	return 0;
+}
+
+static struct buffer *dequeue_buffer(struct impl *this, struct port *port)
+{
+	struct buffer *b;
+
+	if (spa_list_is_empty(&port->queue))
+		return NULL;
+
+	b = spa_list_first(&port->queue, struct buffer, link);
+	spa_list_remove(&b->link);
+	SPA_FLAG_UNSET(b->flags, BUFFER_FLAG_QUEUED);
+	spa_log_trace(this->log, NAME " %p: dequeue buffer %d", this, b->buffer->id);
+	return b;
+}
+
+static int port_set_format(struct spa_node *node,
+			   enum spa_direction direction,
+			   uint32_t port_id,
+			   uint32_t flags,
+			   const struct spa_pod *format)
+{
+	struct impl *this = SPA_CONTAINER_OF(node, struct impl, node);
+	struct port *port;
+	struct type *t = &this->type;
+
+	port = GET_PORT(this, direction, port_id);
+
+	if (format == NULL) {
+		if (port->have_format) {
+			port->have_format = false;
+			if (--this->n_formats == 0)
+				this->have_format = false;
+			clear_buffers(this, port);
+		}
+	} else {
+		struct spa_audio_info info = { 0 };
+
+		spa_pod_object_parse(format,
+			"I", &info.media_type,
+			"I", &info.media_subtype);
+
+		if (info.media_type != t->media_type.audio ||
+		    info.media_subtype != t->media_subtype.raw)
+			return -EINVAL;
+
+		if (spa_format_audio_raw_parse(format, &info.info.raw, &t->format_audio) < 0)
+			return -EINVAL;
+
+		if (this->have_format) {
+			if (memcmp(&info, &this->format, sizeof(struct spa_audio_info)))
+				return -EINVAL;
+		} else {
+			if (info.info.raw.format != t->audio_format.F32)
+				return -EINVAL;
+
+			this->stride = sizeof(float);
+			this->have_format = true;
+			this->format = info;
+		}
+		if (!port->have_format) {
+			this->n_formats++;
+			port->have_format = true;
+			spa_log_info(this->log, NAME " %p: set format on port %d:%d",
+					this, direction, port_id);
+		}
+	}
+
+	return 0;
+}
+
+
+static int
+impl_node_port_set_param(struct spa_node *node,
+			 enum spa_direction direction, uint32_t port_id,
+			 uint32_t id, uint32_t flags,
+			 const struct spa_pod *param)
+{
+	struct impl *this;
+	struct type *t;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+	t = &this->type;
+
+	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
+
+	if (id == t->param.idFormat) {
+		return port_set_format(node, direction, port_id, flags, param);
+	}
+	else
+		return -ENOENT;
+}
+
+static int
+impl_node_port_use_buffers(struct spa_node *node,
+			   enum spa_direction direction,
+			   uint32_t port_id,
+			   struct spa_buffer **buffers,
+			   uint32_t n_buffers)
+{
+	struct impl *this;
+	struct port *port;
+	uint32_t i;
+	struct type *t;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+	t = &this->type;
+
+	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
+
+	port = GET_PORT(this, direction, port_id);
+
+	spa_return_val_if_fail(port->have_format, -EIO);
+
+	spa_log_info(this->log, NAME " %p: use buffers %d on port %d:%d",
+			this, n_buffers, direction, port_id);
+
+	clear_buffers(this, port);
+
+	for (i = 0; i < n_buffers; i++) {
+		struct buffer *b;
+		struct spa_data *d = buffers[i]->datas;
+
+		b = &port->buffers[i];
+		b->buffer = buffers[i];
+		b->flags = 0;
+		b->id = i;
+		b->h = spa_buffer_find_meta_data(buffers[i], t->meta.Header, sizeof(*b->h));
+
+		if (!((d[0].type == t->data.MemPtr ||
+		       d[0].type == t->data.MemFd ||
+		       d[0].type == t->data.DmaBuf) && d[0].data != NULL)) {
+			spa_log_error(this->log, NAME " %p: invalid memory on buffer %p", this,
+				      buffers[i]);
+			return -EINVAL;
+		}
+		if (direction == SPA_DIRECTION_OUTPUT)
+			queue_buffer(this, port, b);
+	}
+	port->n_buffers = n_buffers;
+
+	return 0;
+}
+
+static int
+impl_node_port_alloc_buffers(struct spa_node *node,
+			     enum spa_direction direction,
+			     uint32_t port_id,
+			     struct spa_pod **params,
+			     uint32_t n_params,
+			     struct spa_buffer **buffers,
+			     uint32_t *n_buffers)
+{
+	return -ENOTSUP;
+}
+
+static int
+impl_node_port_set_io(struct spa_node *node,
+		      enum spa_direction direction, uint32_t port_id,
+		      uint32_t id, void *data, size_t size)
+{
+	struct impl *this;
+	struct port *port;
+	struct type *t;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+	t = &this->type;
+
+	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
+
+	port = GET_PORT(this, direction, port_id);
+
+	if (id == t->io.Buffers)
+		port->io = data;
+	else if (id == t->io.ControlRange)
+		port->ctrl = data;
+	else if (id == t->io_prop_volume && direction == SPA_DIRECTION_INPUT)
+		if (data && size >= sizeof(struct spa_pod_double))
+			port->io_volume = &SPA_POD_VALUE(struct spa_pod_double, data);
+		else
+			port->io_volume = &port->props.volume;
+	else if (id == t->io_prop_mute && direction == SPA_DIRECTION_INPUT)
+		if (data && size >= sizeof(struct spa_pod_bool))
+			port->io_mute = &SPA_POD_VALUE(struct spa_pod_bool, data);
+		else
+			port->io_mute = &port->props.mute;
+	else
+		return -ENOENT;
+
+	return 0;
+}
+
+static int impl_node_port_reuse_buffer(struct spa_node *node, uint32_t port_id, uint32_t buffer_id)
+{
+	struct impl *this;
+	struct port *port;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+
+	spa_return_val_if_fail(CHECK_PORT(this, SPA_DIRECTION_OUTPUT, port_id), -EINVAL);
+	port = GET_OUT_PORT(this, 0);
+
+	if (buffer_id >= port->n_buffers)
+		return -EINVAL;
+
+	return queue_buffer(this, port, &port->buffers[buffer_id]);
+}
+
+static int
+impl_node_port_send_command(struct spa_node *node,
+			    enum spa_direction direction,
+			    uint32_t port_id,
+			    const struct spa_command *command)
+{
+	return -ENOTSUP;
+}
+
+
+#if defined (__SSE__)
+#include <xmmintrin.h>
+static void mix_2(float *dst, float *src1, float *src2, int n_samples)
+{
+	int i, unrolled;
+	__m128 in[2];
+
+	unrolled = n_samples / 4;
+	n_samples &= 3;
+
+	for (i = 0; unrolled--; i += 4) {
+		in[0] = _mm_loadu_ps(&src1[i]),
+		in[1] = _mm_loadu_ps(&src2[i]),
+		in[0] = _mm_add_ps(in[0], in[1]);
+		_mm_storeu_ps(&dst[i], in[0]);
+	}
+	for (; n_samples--; i++) {
+		in[0] = _mm_load_ss(&src1[i]),
+		in[1] = _mm_load_ss(&src2[i]),
+		in[0] = _mm_add_ss(in[0], in[1]);
+		_mm_store_ss(&dst[i], in[0]);
+	}
+}
+#else
+static void mix_2(float *dst, float *src1, float *src2, int n_samples)
+{
+	int i;
+	for (i = 0; i < n_samples; i++)
+		dst[i] = src1[i] + src2[i];
+}
+#endif
+
+
+static int impl_node_process(struct spa_node *node)
+{
+	struct impl *this;
+	struct port *outport;
+	struct spa_io_buffers *outio;
+	int n_samples, n_buffers, i, maxsize;
+        struct buffer **buffers;
+        struct buffer *outb;
+
+	spa_return_val_if_fail(node != NULL, -EINVAL);
+
+	this = SPA_CONTAINER_OF(node, struct impl, node);
+
+	outport = GET_OUT_PORT(this, 0);
+	outio = outport->io;
+	spa_return_val_if_fail(outio != NULL, -EIO);
+
+	spa_log_trace(this->log, NAME " %p: status %d %d", this, outio->status, outio->buffer_id);
+
+	if (outio->status == SPA_STATUS_HAVE_BUFFER)
+		return outio->status;
+
+	/* recycle */
+	if (outio->buffer_id < outport->n_buffers) {
+		queue_buffer(this, outport, &outport->buffers[outio->buffer_id]);
+		outio->buffer_id = SPA_ID_INVALID;
+	}
+
+        buffers = alloca(MAX_PORTS * sizeof(struct buffer *));
+        n_buffers = 0;
+
+	maxsize = MAX_SAMPLES * sizeof(float);
+	if (outport->ctrl)
+		maxsize = SPA_MIN(outport->ctrl->max_size, maxsize);
+
+	for (i = 0; i < this->last_port; i++) {
+		struct port *inport = GET_IN_PORT(this, i);
+		struct spa_io_buffers *inio = NULL;
+		struct buffer *inb;
+
+		if (!inport->valid ||
+		    (inio = inport->io) == NULL ||
+		    inio->buffer_id >= inport->n_buffers ||
+		    inio->status != SPA_STATUS_HAVE_BUFFER) {
+			spa_log_trace(this->log, NAME " %p: skip input %d %d %p %d %d %d", this,
+				i, inport->valid, inio,
+				inio ? inio->status : -1,
+				inio ? inio->buffer_id : -1,
+				inport->n_buffers);
+			continue;
+		}
+
+		spa_log_trace(this->log, NAME " %p: mix input %d %p->%p %d %d", this,
+				i, inio, outio, inio->status, inio->buffer_id);
+
+		inb = &inport->buffers[inio->buffer_id];
+
+		maxsize = SPA_MIN(inb->buffer->datas[0].chunk->size, maxsize);
+
+		buffers[n_buffers++] = inb;
+		inio->status = SPA_STATUS_NEED_BUFFER;
+	}
+
+	outb = dequeue_buffer(this, outport);
+        if (outb == NULL) {
+                spa_log_trace(this->log, NAME " %p: out of buffers", this);
+                return -EPIPE;
+        }
+
+	n_samples = maxsize / sizeof(float);
+
+	if (n_buffers == 1) {
+		*outb->buffer = *buffers[0]->buffer;
+		outb->buffer->id = outb->id;
+	}
+	else {
+		float *dst;
+
+		outb->buffer->id = outb->id;
+		outb->buffer->n_datas = 1;
+		outb->buffer->datas = outb->datas;
+		outb->datas[0].data = this->empty;
+		outb->datas[0].chunk = outb->chunk;
+		outb->datas[0].chunk->offset = 0;
+		outb->datas[0].chunk->size = n_samples * sizeof(float);
+		outb->datas[0].chunk->stride = sizeof(float);
+
+		dst = this->empty;
+		if (n_buffers == 0) {
+			memset(dst, 0, n_samples * sizeof(float));
+		}
+		else {
+			/* first 2 buffers, add and store */
+			mix_2(dst, buffers[0]->buffer->datas[0].data,
+				   buffers[1]->buffer->datas[0].data, n_samples);
+			/* next buffers */
+			for (i = 2; i < n_buffers; i++)
+				mix_2(dst, dst, buffers[i]->buffer->datas[0].data, n_samples);
+		}
+	}
+
+	outio->buffer_id = outb->buffer->id;
+	outio->status = SPA_STATUS_HAVE_BUFFER;
+
+	return SPA_STATUS_HAVE_BUFFER | SPA_STATUS_NEED_BUFFER;
+}
+
+static const struct spa_node impl_node = {
+	SPA_VERSION_NODE,
+	NULL,
+	impl_node_enum_params,
+	impl_node_set_param,
+	impl_node_send_command,
+	impl_node_set_callbacks,
+	impl_node_get_n_ports,
+	impl_node_get_port_ids,
+	impl_node_add_port,
+	impl_node_remove_port,
+	impl_node_port_get_info,
+	impl_node_port_enum_params,
+	impl_node_port_set_param,
+	impl_node_port_use_buffers,
+	impl_node_port_alloc_buffers,
+	impl_node_port_set_io,
+	impl_node_port_reuse_buffer,
+	impl_node_port_send_command,
+	impl_node_process,
+};
+
+static int impl_get_interface(struct spa_handle *handle, uint32_t interface_id, 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 (interface_id == this->type.node)
+		*interface = &this->node;
+	else
+		return -ENOENT;
+
+	return 0;
+}
+
+static int impl_clear(struct spa_handle *handle)
+{
+	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;
+	struct port *port;
+	uint32_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;
+
+	for (i = 0; i < n_support; i++) {
+		if (strcmp(support[i].type, SPA_TYPE__TypeMap) == 0)
+			this->map = support[i].data;
+		else if (strcmp(support[i].type, SPA_TYPE__Log) == 0)
+			this->log = support[i].data;
+	}
+	if (this->map == NULL) {
+		spa_log_error(this->log, "an id-map is needed");
+		return -EINVAL;
+	}
+	init_type(&this->type, this->map);
+
+	this->node = impl_node;
+
+	port = GET_OUT_PORT(this, 0);
+	port->valid = true;
+	port->id = 0;
+	port->info.flags = SPA_PORT_INFO_FLAG_CAN_USE_BUFFERS |
+	    SPA_PORT_INFO_FLAG_NO_REF;
+	spa_list_init(&port->queue);
+
+	return 0;
+}
+
+static const struct spa_interface_info impl_interfaces[] = {
+	{SPA_TYPE__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;
+}
+
+const struct spa_handle_factory spa_floatmix_factory = {
+	SPA_VERSION_HANDLE_FACTORY,
+	NAME,
+	NULL,
+	impl_get_size,
+	impl_init,
+	impl_enum_interface_info,
+};