pipewire/src/examples/audio-src.c

/* PipeWire
 * 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 <stdio.h>
#include <errno.h>
#include <time.h>
#include <math.h>
#include <sys/mman.h>

#include <spa/support/type-map.h>
#include <spa/param/format-utils.h>
#include <spa/param/audio/format-utils.h>
#include <spa/param/props.h>
#include <spa/lib/debug.h>

#include <pipewire/pipewire.h>

#define M_PI_M2 ( M_PI + M_PI )

#define DEFAULT_RATE		44100
#define DEFAULT_CHANNELS	1

struct type {
	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;
};

static inline void init_type(struct type *type, struct spa_type_map *map)
{
	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);
}

struct data {
	struct type type;

	struct pw_main_loop *loop;

	struct pw_core *core;
	struct pw_type *t;
	struct pw_remote *remote;

	struct pw_stream *stream;

	double accumulator;
};

static void fill_f32(struct data *d, void *dest, int avail)
{
	float *dst = dest, val;
	int n_samples = avail / (sizeof(float) * DEFAULT_CHANNELS);
	int i, c;

        for (i = 0; i < n_samples; i++) {
                d->accumulator += M_PI_M2 * 440 / DEFAULT_RATE;
                if (d->accumulator >= M_PI_M2)
                        d->accumulator -= M_PI_M2;

                val = sin(d->accumulator);
                for (c = 0; c < DEFAULT_CHANNELS; c++)
                        *dst++ = val;
        }
}

static void on_process(void *userdata)
{
	struct data *data = userdata;
	struct pw_buffer *b;
	struct spa_buffer *buf;
	uint8_t *p;

	if ((b = pw_stream_dequeue_buffer(data->stream)) == NULL)
		return;

	buf = b->buffer;
	if ((p = buf->datas[0].data) == NULL)
		return;

	fill_f32(data, p, buf->datas[0].maxsize);

	buf->datas[0].chunk->size = buf->datas[0].maxsize;

	pw_stream_queue_buffer(data->stream, b);
}

static const struct pw_stream_events stream_events = {
	PW_VERSION_STREAM_EVENTS,
	.process = on_process,
};

int main(int argc, char *argv[])
{
	struct data data = { 0, };
	const struct spa_pod *params[1];
	uint8_t buffer[1024];
	struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));

	pw_init(&argc, &argv);

	data.loop = pw_main_loop_new(NULL);

	data.stream = pw_stream_new_simple(
			pw_main_loop_get_loop(data.loop),
			"audio-src",
			NULL,
			&stream_events,
			&data);

	data.remote = pw_stream_get_remote(data.stream);
	data.t = pw_core_get_type(pw_remote_get_core(data.remote));
	init_type(&data.type, data.t->map);

	params[0] = spa_pod_builder_object(&b,
		data.t->param.idEnumFormat, data.t->spa_format,
		"I", data.type.media_type.audio,
		"I", data.type.media_subtype.raw,
		":", data.type.format_audio.format,	"I", data.type.audio_format.F32,
		":", data.type.format_audio.channels,	"i", DEFAULT_CHANNELS,
		":", data.type.format_audio.rate,	"i", DEFAULT_RATE);

	pw_stream_connect(data.stream,
			  PW_DIRECTION_OUTPUT,
			  argc > 1 ? argv[1] : NULL,
			  PW_STREAM_FLAG_AUTOCONNECT |
			  PW_STREAM_FLAG_MAP_BUFFERS |
			  PW_STREAM_FLAG_RT_PROCESS,
			  params, 1);

	pw_main_loop_run(data.loop);

	pw_stream_destroy(data.stream);
	pw_main_loop_destroy(data.loop);

	return 0;
}