pipewire/spa/plugins/audioconvert/channelmix.c

/* 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/utils/list.h>
#include <spa/node/node.h>
#include <spa/node/io.h>
#include <spa/param/audio/format-utils.h>
#include <spa/param/param.h>
#include <spa/pod/filter.h>
#include <spa/control/control.h>

#define NAME "channelmix"

#define DEFAULT_RATE		44100
#define DEFAULT_CHANNELS	2

#define MAX_BUFFERS     32

struct impl;

#define DEFAULT_VOLUME	1.0

struct props {
	float volume;
};

static void props_reset(struct props *props)
{
	props->volume = DEFAULT_VOLUME;
}

struct buffer {
	struct spa_list link;
#define BUFFER_FLAG_OUT		(1 << 0)
	uint32_t flags;
	struct spa_buffer *outbuf;
	struct spa_meta_header *h;
};

struct port {
	uint32_t id;

	struct spa_io_buffers *io;
	struct spa_io_sequence *control;
	struct spa_port_info info;

	bool have_format;
	struct spa_audio_info format;
	uint32_t stride;
	uint32_t blocks;
	uint32_t size;

	struct buffer buffers[MAX_BUFFERS];
	uint32_t n_buffers;

	struct spa_list queue;
};

#include "channelmix-ops.c"

struct impl {
	struct spa_handle handle;
	struct spa_node node;

	struct spa_log *log;

	struct props props;

	const struct spa_node_callbacks *callbacks;
	void *user_data;

	struct port in_port;
	struct port out_port;

	bool started;

	channelmix_func_t convert;
	float matrix[4096];
};

#define CHECK_PORT(this,d,id)		(id == 0)
#define GET_IN_PORT(this,id)		(&this->in_port)
#define GET_OUT_PORT(this,id)		(&this->out_port)
#define GET_PORT(this,d,id)		(d == SPA_DIRECTION_INPUT ? GET_IN_PORT(this,id) : GET_OUT_PORT(this,id))

static void setup_matrix(struct impl *this,
		const struct spa_audio_info *src_info,
		const struct spa_audio_info *dst_info)
{
	uint32_t src_chan, dst_chan;
	int i, j;

	src_chan = src_info->info.raw.channels;
	dst_chan = dst_info->info.raw.channels;

	for (i = 0; i < dst_chan; i++) {
		for (j = 0; j < src_chan; j++) {
			if (i == j)
				this->matrix[i * src_chan + j] = this->props.volume;
			else
				this->matrix[i * src_chan + j] = 0.0f;
		}
	}
}

static int setup_convert(struct impl *this,
		enum spa_direction direction,
		const struct spa_audio_info *info)
{
	const struct spa_audio_info *src_info, *dst_info;
	uint32_t src_chan, dst_chan;
	const struct channelmix_info *chanmix_info;

	if (direction == SPA_DIRECTION_INPUT) {
		src_info = info;
		dst_info = &GET_OUT_PORT(this, 0)->format;
	} else {
		src_info = &GET_IN_PORT(this, 0)->format;
		dst_info = info;
	}

	src_chan = src_info->info.raw.channels;
	dst_chan = dst_info->info.raw.channels;

	spa_log_info(this->log, NAME " %p: %d/%d@%d->%d/%d@%d", this,
			src_info->info.raw.format,
			src_chan,
			src_info->info.raw.rate,
			dst_info->info.raw.format,
			dst_chan,
			dst_info->info.raw.rate);

	if (src_info->info.raw.rate != dst_info->info.raw.rate)
		return -EINVAL;

	/* find convert function */
	if ((chanmix_info = find_channelmix_info(src_chan, 0, dst_chan, 0, FEATURE_SSE)) == NULL)
		return -ENOTSUP;

	spa_log_info(this->log, NAME " %p: got channelmix features %08x", this, chanmix_info->features);

	this->convert = chanmix_info->func;

	/* set up the matrix if needed */
	setup_matrix(this, src_info, dst_info);

	return 0;
}

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);

	switch (SPA_NODE_COMMAND_ID(command)) {
	case SPA_NODE_COMMAND_Start:
		this->started = true;
		break;
	case SPA_NODE_COMMAND_Pause:
		this->started = false;
		break;
	default:
		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)
{
	spa_return_val_if_fail(node != NULL, -EINVAL);

	if (n_input_ports)
		*n_input_ports = 1;
	if (max_input_ports)
		*max_input_ports = 1;
	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)
{
	spa_return_val_if_fail(node != NULL, -EINVAL);

	if (n_input_ids && input_ids)
		input_ids[0] = 0;
	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)
{
	return -ENOTSUP;
}

static int
impl_node_remove_port(struct spa_node *node, enum spa_direction direction, uint32_t port_id)
{
	return -ENOTSUP;
}

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 port *other;

	other = GET_PORT(this, SPA_DIRECTION_REVERSE(direction), 0);

	switch (*index) {
	case 0:
		if (other->have_format) {
			*param = spa_pod_builder_object(builder,
				SPA_TYPE_OBJECT_Format, SPA_PARAM_EnumFormat,
				SPA_FORMAT_mediaType,      &SPA_POD_Id(SPA_MEDIA_TYPE_audio),
				SPA_FORMAT_mediaSubtype,   &SPA_POD_Id(SPA_MEDIA_SUBTYPE_raw),
				SPA_FORMAT_AUDIO_format,   &SPA_POD_Id(SPA_AUDIO_FORMAT_F32P),
				SPA_FORMAT_AUDIO_rate,     &SPA_POD_Int(other->format.info.raw.rate),
				SPA_FORMAT_AUDIO_channels, &SPA_POD_CHOICE_RANGE_Int(DEFAULT_CHANNELS, 1, INT32_MAX),
				0);
		} else {
			*param = spa_pod_builder_object(builder,
				SPA_TYPE_OBJECT_Format, SPA_PARAM_EnumFormat,
				SPA_FORMAT_mediaType,      &SPA_POD_Id(SPA_MEDIA_TYPE_audio),
				SPA_FORMAT_mediaSubtype,   &SPA_POD_Id(SPA_MEDIA_SUBTYPE_raw),
				SPA_FORMAT_AUDIO_format,   &SPA_POD_Id(SPA_AUDIO_FORMAT_F32P),
				SPA_FORMAT_AUDIO_rate,     &SPA_POD_CHOICE_RANGE_Int(DEFAULT_RATE, 1, INT32_MAX),
				SPA_FORMAT_AUDIO_channels, &SPA_POD_CHOICE_RANGE_Int(DEFAULT_CHANNELS, 1, INT32_MAX),
				0);
		}
		break;
	default:
		return 0;
	}
	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 port *port, *other;
	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);

	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);

	port = GET_PORT(this, direction, port_id);
	other = GET_PORT(this, SPA_DIRECTION_REVERSE(direction), port_id);

      next:
	spa_pod_builder_init(&b, buffer, sizeof(buffer));

	switch (id) {
	case SPA_PARAM_List:
	{
		uint32_t list[] = { SPA_PARAM_EnumFormat,
				    SPA_PARAM_Format,
				    SPA_PARAM_Buffers,
				    SPA_PARAM_Meta,
				    SPA_PARAM_IO };

		if (*index < SPA_N_ELEMENTS(list))
			param = spa_pod_builder_object(&b,
					SPA_TYPE_OBJECT_ParamList, id,
					SPA_PARAM_LIST_id, &SPA_POD_Id(list[*index]),
					0);
		else
			return 0;
		break;
	}
	case SPA_PARAM_EnumFormat:
		if ((res = port_enum_formats(node, direction, port_id, index, &param, &b)) <= 0)
			return res;
		break;

	case SPA_PARAM_Format:
		if (!port->have_format)
			return -EIO;
		if (*index > 0)
			return 0;

		param = spa_format_audio_raw_build(&b, id, &port->format.info.raw);
		break;

	case SPA_PARAM_Buffers:
	{
		uint32_t buffers, size;

		if (!port->have_format)
			return -EIO;
		if (*index > 0)
			return 0;

		if (other->n_buffers > 0) {
			buffers = other->n_buffers;
			size = other->size / other->stride;
		} else {
			buffers = 1;
			size = port->format.info.raw.rate * 1024 / DEFAULT_RATE;
		}

		param = spa_pod_builder_object(&b,
			SPA_TYPE_OBJECT_ParamBuffers, id,
			SPA_PARAM_BUFFERS_buffers, &SPA_POD_CHOICE_RANGE_Int(buffers, 1, MAX_BUFFERS),
			SPA_PARAM_BUFFERS_blocks,  &SPA_POD_Int(port->blocks),
			SPA_PARAM_BUFFERS_size,    &SPA_POD_CHOICE_RANGE_Int(
							size * port->stride,
							16 * port->stride,
							INT32_MAX / port->stride),
			SPA_PARAM_BUFFERS_stride,  &SPA_POD_Int(port->stride),
			SPA_PARAM_BUFFERS_align,   &SPA_POD_Int(16),
			0);
		break;
	}
	case SPA_PARAM_Meta:
		if (!port->have_format)
			return -EIO;

		switch (*index) {
		case 0:
			param = spa_pod_builder_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)),
				0);
			break;
		default:
			return 0;
		}
		break;

	case SPA_PARAM_IO:
		switch (*index) {
		case 0:
			param = spa_pod_builder_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)),
				0);
			break;
		case 1:
			param = spa_pod_builder_object(&b,
				SPA_TYPE_OBJECT_ParamIO, id,
				SPA_PARAM_IO_id,   &SPA_POD_Id(SPA_IO_Control),
				SPA_PARAM_IO_size, &SPA_POD_Int(sizeof(struct spa_io_sequence)),
				0);
			break;
		default:
			return 0;
		}
		break;
	default:
		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_debug(this->log, NAME " %p: clear buffers %p", this, port);
		port->n_buffers = 0;
		spa_list_init(&port->queue);
	}
	return 0;
}

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, *other;
	int res = 0;

	port = GET_PORT(this, direction, port_id);
	other = GET_PORT(this, SPA_DIRECTION_REVERSE(direction), port_id);

	if (format == NULL) {
		if (port->have_format) {
			port->have_format = false;
			clear_buffers(this, port);
		}
		this->convert = NULL;
	} else {
		struct spa_audio_info info = { 0 };

		if ((res = spa_format_parse(format, &info.media_type, &info.media_subtype)) < 0)
			return res;

		if (info.media_type != SPA_MEDIA_TYPE_audio ||
		    info.media_subtype != SPA_MEDIA_SUBTYPE_raw)
			return -EINVAL;

		if (spa_format_audio_raw_parse(format, &info.info.raw) < 0)
			return -EINVAL;

		if (info.info.raw.format != SPA_AUDIO_FORMAT_F32P)
			return -EINVAL;

		port->stride = sizeof(float);
		port->blocks = info.info.raw.channels;

		if (other->have_format) {
			if ((res = setup_convert(this, direction, &info)) < 0)
				return res;
		}
		port->format = info;
		port->have_format = true;

		spa_log_debug(this->log, NAME " %p: set format on port %d %d", this, port_id, res);
	}
	return res;
}

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)
{
	spa_return_val_if_fail(node != NULL, -EINVAL);

	spa_return_val_if_fail(CHECK_PORT(node, direction, port_id), -EINVAL);

	if (id == SPA_PARAM_Format) {
		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, size = SPA_ID_INVALID;

	spa_return_val_if_fail(node != 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);

	spa_return_val_if_fail(port->have_format, -EIO);

	spa_log_debug(this->log, NAME " %p: use buffers %d on port %d", this, n_buffers, 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->flags = 0;
		b->outbuf = buffers[i];
		b->h = spa_buffer_find_meta_data(buffers[i], SPA_META_Header, sizeof(*b->h));

		if (size == SPA_ID_INVALID)
			size = d[0].maxsize;
		else
			if (size != d[0].maxsize)
				return -EINVAL;

		if (!((d[0].type == SPA_DATA_MemPtr ||
		       d[0].type == SPA_DATA_MemFd ||
		       d[0].type == SPA_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)
			spa_list_append(&port->queue, &b->link);
		else
			SPA_FLAG_SET(b->flags, BUFFER_FLAG_OUT);
	}
	port->n_buffers = n_buffers;
	port->size = size;

	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;

	spa_return_val_if_fail(node != 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);

	switch (id) {
	case SPA_IO_Buffers:
		port->io = data;
		break;
	case SPA_IO_Control:
		port->control = data;
		break;
	default:
		return -ENOENT;
	}
	return 0;
}

static void recycle_buffer(struct impl *this, uint32_t id)
{
	struct port *port = GET_OUT_PORT(this, 0);
	struct buffer *b = &port->buffers[id];

	if (SPA_FLAG_CHECK(b->flags, BUFFER_FLAG_OUT)) {
		spa_list_append(&port->queue, &b->link);
		SPA_FLAG_UNSET(b->flags, BUFFER_FLAG_OUT);
		spa_log_trace(this->log, NAME " %p: recycle buffer %d", this, id);
	}
}

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_SET(b->flags, BUFFER_FLAG_OUT);

	return b;
}


static int impl_node_port_reuse_buffer(struct spa_node *node, uint32_t port_id, uint32_t buffer_id)
{
	struct impl *this;

	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);

	recycle_buffer(this, buffer_id);

	return 0;
}

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;
}

static int process_control(struct impl *this, struct port *port, struct spa_pod_sequence *sequence)
{
	struct spa_pod_control *c;

	SPA_POD_SEQUENCE_FOREACH(sequence, c) {
		switch (c->type) {
		case SPA_CONTROL_Properties:
		{
			struct props *p = &this->props;
			float volume = p->volume;
			struct spa_pod_prop *prop;
			struct spa_pod_object *obj = (struct spa_pod_object *) &c->value;

			SPA_POD_OBJECT_FOREACH(obj, prop) {
				switch (prop->key) {
				case SPA_PROP_volume:
					volume = SPA_POD_VALUE(struct spa_pod_float, &prop->value);
					if (volume != p->volume) {
						p->volume = volume;
						setup_matrix(this,
							&GET_IN_PORT(this, 0)->format,
							&GET_OUT_PORT(this, 0)->format);
					}
					break;
				default:
					break;
				}
			}

			break;
		}
		default:
			break;
                }
	}
	return 0;
}

static int impl_node_process(struct spa_node *node)
{
	struct impl *this;
	struct port *outport, *inport;
	struct spa_io_buffers *outio, *inio;
	struct buffer *sbuf, *dbuf;

	spa_return_val_if_fail(node != NULL, -EINVAL);

	this = SPA_CONTAINER_OF(node, struct impl, node);

	outport = GET_OUT_PORT(this, 0);
	inport = GET_IN_PORT(this, 0);

	outio = outport->io;
	inio = inport->io;

	spa_return_val_if_fail(outio != NULL, -EIO);
	spa_return_val_if_fail(inio != NULL, -EIO);

	spa_log_trace(this->log, NAME " %p: status %d %d", this, inio->status, outio->status);

	if (outport->control)
		process_control(this, outport, &outport->control->sequence);

	if (outio->status == SPA_STATUS_HAVE_BUFFER)
		goto done;

	if (inio->status != SPA_STATUS_HAVE_BUFFER)
		return SPA_STATUS_NEED_BUFFER;

	/* recycle */
	if (outio->buffer_id < outport->n_buffers) {
		recycle_buffer(this, outio->buffer_id);
		outio->buffer_id = SPA_ID_INVALID;
	}

	if (inio->buffer_id >= inport->n_buffers)
		return inio->status = -EINVAL;

	if ((dbuf = dequeue_buffer(this, outport)) == NULL)
		return outio->status = -EPIPE;

	sbuf = &inport->buffers[inio->buffer_id];

	{
		int i, n_bytes;
		struct spa_buffer *sb = sbuf->outbuf, *db = dbuf->outbuf;
		uint32_t n_src_datas = sb->n_datas;
		uint32_t n_dst_datas = db->n_datas;
		const void *src_datas[n_src_datas];
		void *dst_datas[n_dst_datas];

		n_bytes = sb->datas[0].chunk->size;

		for (i = 0; i < n_src_datas; i++)
			src_datas[i] = sb->datas[i].data;
		for (i = 0; i < n_dst_datas; i++) {
			dst_datas[i] = db->datas[i].data;
			db->datas[i].chunk->size =
				(n_bytes / inport->stride) * outport->stride;
		}

		this->convert(this, n_dst_datas, dst_datas,
				    n_src_datas, src_datas,
				    this->matrix, n_bytes);
	}

	outio->status = SPA_STATUS_HAVE_BUFFER;
	outio->buffer_id = dbuf->outbuf->id;

	inio->status = SPA_STATUS_NEED_BUFFER;

      done:
	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 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 (type == SPA_TYPE_INTERFACE_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 (support[i].type == SPA_TYPE_INTERFACE_Log)
			this->log = support[i].data;
	}

	this->node = impl_node;

	port = GET_OUT_PORT(this, 0);
	port->id = 0;
	port->info.flags = SPA_PORT_INFO_FLAG_CAN_USE_BUFFERS;
	spa_list_init(&port->queue);

	port = GET_IN_PORT(this, 0);
	port->id = 0;
	port->info.flags = SPA_PORT_INFO_FLAG_CAN_USE_BUFFERS;
	spa_list_init(&port->queue);

	props_reset(&this->props);

	return 0;
}

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;
}

const struct spa_handle_factory spa_channelmix_factory = {
	SPA_VERSION_HANDLE_FACTORY,
	NAME,
	NULL,
	impl_get_size,
	impl_init,
	impl_enum_interface_info,
};