PipeWire 1.2.6

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audio-dsp-src.c

Audio source using pw_filter

Audio source using pw_filter

/* PipeWire */
/* SPDX-FileCopyrightText: Copyright © 2020 Wim Taymans */
/* SPDX-License-Identifier: MIT */
/*
[title]
Audio source using \ref pw_filter "pw_filter"
[title]
*/
#include <stdio.h>
#include <errno.h>
#include <math.h>
#include <signal.h>
#include <pipewire/pipewire.h>
#include <pipewire/filter.h>
#define M_PI_M2f (float)(M_PI+M_PI)
#define DEFAULT_RATE 44100
#define DEFAULT_FREQ 440
#define DEFAULT_VOLUME 0.7f
struct data;
struct port {
struct data *data;
float accumulator;
};
struct data {
struct pw_main_loop *loop;
struct pw_filter *filter;
struct port *out_port;
};
/* our data processing function is in general:
*
* struct pw_buffer *b;
* out = pw_filter_dequeue_buffer(filter, out_port);
*
* .. generate data in the buffer ...
*
* pw_filter_queue_buffer(filter, out_port, out);
*
* For DSP ports, there is a shortcut to directly dequeue, get
* the data and requeue the buffer with pw_filter_get_dsp_buffer().
*/
static void on_process(void *userdata, struct spa_io_position *position)
{
struct data *data = userdata;
float *out;
struct port *out_port = data->out_port;
uint32_t i, n_samples = position->clock.duration;
pw_log_trace("do process %d", n_samples);
out = pw_filter_get_dsp_buffer(out_port, n_samples);
if (out == NULL)
return;
for (i = 0; i < n_samples; i++) {
out_port->accumulator += M_PI_M2f * DEFAULT_FREQ / DEFAULT_RATE;
if (out_port->accumulator >= M_PI_M2f)
out_port->accumulator -= M_PI_M2f;
*out++ = sinf(out_port->accumulator) * DEFAULT_VOLUME;
}
}
static const struct pw_filter_events filter_events = {
PW_VERSION_FILTER_EVENTS,
.process = on_process,
};
static void do_quit(void *userdata, int signal_number)
{
struct data *data = userdata;
pw_main_loop_quit(data->loop);
}
int main(int argc, char *argv[])
{
struct data data = { 0, };
pw_init(&argc, &argv);
/* make a main loop. If you already have another main loop, you can add
* the fd of this pipewire mainloop to it. */
data.loop = pw_main_loop_new(NULL);
pw_loop_add_signal(pw_main_loop_get_loop(data.loop), SIGINT, do_quit, &data);
pw_loop_add_signal(pw_main_loop_get_loop(data.loop), SIGTERM, do_quit, &data);
/* Create a simple filter, the simple filter manages the core and remote
* objects for you if you don't need to deal with them.
*
* Pass your events and a user_data pointer as the last arguments. This
* will inform you about the filter state. The most important event
* you need to listen to is the process event where you need to process
* the data.
*/
data.filter = pw_filter_new_simple(
pw_main_loop_get_loop(data.loop),
"audio-dsp-src",
pw_properties_new(
PW_KEY_MEDIA_TYPE, "Audio",
PW_KEY_MEDIA_CATEGORY, "Source",
PW_KEY_MEDIA_ROLE, "DSP",
PW_KEY_MEDIA_CLASS, "Stream/Output/Audio",
PW_KEY_NODE_AUTOCONNECT, "true",
NULL),
&filter_events,
&data);
/* make an audio DSP output port */
data.out_port = pw_filter_add_port(data.filter,
PW_DIRECTION_OUTPUT,
PW_FILTER_PORT_FLAG_MAP_BUFFERS,
sizeof(struct port),
pw_properties_new(
PW_KEY_FORMAT_DSP, "32 bit float mono audio",
PW_KEY_PORT_NAME, "output",
NULL),
NULL, 0);
/* Now connect this filter. We ask that our process function is
* called in a realtime thread. */
if (pw_filter_connect(data.filter,
PW_FILTER_FLAG_RT_PROCESS,
NULL, 0) < 0) {
fprintf(stderr, "can't connect\n");
return -1;
}
/* and wait while we let things run */
pw_main_loop_run(data.loop);
pw_filter_destroy(data.filter);
pw_main_loop_destroy(data.loop);
pw_deinit();
return 0;
}
pw_filter_connect
int pw_filter_connect(struct pw_filter *filter, enum pw_filter_flags flags, const struct spa_pod **params, uint32_t n_params)
Connect a filter for processing.
Definition filter.c:1548
pw_filter_add_port
void * pw_filter_add_port(struct pw_filter *filter, enum pw_direction direction, enum pw_filter_port_flags flags, size_t port_data_size, struct pw_properties *props, const struct spa_pod **params, uint32_t n_params)
add a port to the filter, returns user data of port_data_size.
Definition filter.c:1780
PW_VERSION_FILTER_EVENTS
#define PW_VERSION_FILTER_EVENTS
Definition filter.h:66
pw_filter_destroy
void pw_filter_destroy(struct pw_filter *filter)
Destroy a filter
Definition filter.c:1385
pw_filter_get_dsp_buffer
void * pw_filter_get_dsp_buffer(void *port_data, uint32_t n_samples)
Get a data pointer to the buffer data.
Definition filter.c:2003
pw_filter_new_simple
struct pw_filter * pw_filter_new_simple(struct pw_loop *loop, const char *name, struct pw_properties *props, const struct pw_filter_events *events, void *data)
Definition filter.c:1281
PW_FILTER_FLAG_RT_PROCESS
@ PW_FILTER_FLAG_RT_PROCESS
call process from the realtime thread
Definition filter.h:108
PW_FILTER_PORT_FLAG_MAP_BUFFERS
@ PW_FILTER_PORT_FLAG_MAP_BUFFERS
mmap the buffers except DmaBuf that is not explicitly marked as mappable.
Definition filter.h:129
PW_KEY_PORT_NAME
#define PW_KEY_PORT_NAME
port name
Definition keys.h:324
PW_KEY_MEDIA_TYPE
#define PW_KEY_MEDIA_TYPE
Media.
Definition keys.h:486
PW_KEY_NODE_AUTOCONNECT
#define PW_KEY_NODE_AUTOCONNECT
node wants to be automatically connected to a compatible node
Definition keys.h:235
PW_KEY_MEDIA_ROLE
#define PW_KEY_MEDIA_ROLE
Role: Movie, Music, Camera, Screen, Communication, Game, Notification, DSP, Production,...
Definition keys.h:492
PW_KEY_MEDIA_CATEGORY
#define PW_KEY_MEDIA_CATEGORY
Media Category: Playback, Capture, Duplex, Monitor, Manager.
Definition keys.h:489
PW_KEY_FORMAT_DSP
#define PW_KEY_FORMAT_DSP
format related properties
Definition keys.h:529
PW_KEY_MEDIA_CLASS
#define PW_KEY_MEDIA_CLASS
class Ex: "Video/Source"
Definition keys.h:497
pw_log_trace
#define pw_log_trace(...)
Definition log.h:182
pw_loop_add_signal
#define pw_loop_add_signal(l,...)
Definition loop.h:68
pw_main_loop_quit
int pw_main_loop_quit(struct pw_main_loop *loop)
Quit a main loop.
Definition main-loop.c:108
pw_main_loop_destroy
void pw_main_loop_destroy(struct pw_main_loop *loop)
Destroy a loop.
Definition main-loop.c:73
pw_main_loop_run
int pw_main_loop_run(struct pw_main_loop *loop)
Run a main loop.
Definition main-loop.c:122
pw_main_loop_new
struct pw_main_loop * pw_main_loop_new(const struct spa_dict *props)
Create a new main loop.
Definition main-loop.c:63
pw_main_loop_get_loop
struct pw_loop * pw_main_loop_get_loop(struct pw_main_loop *loop)
Get the loop implementation.
Definition main-loop.c:96
pw_init
void pw_init(int *argc, char **argv[])
Initialize PipeWire.
Definition pipewire.c:488
pw_deinit
void pw_deinit(void)
Deinitialize PipeWire.
Definition pipewire.c:600
PW_DIRECTION_OUTPUT
#define PW_DIRECTION_OUTPUT
Definition port.h:50
pw_properties_new
struct pw_properties * pw_properties_new(const char *key,...)
Make a new properties object.
Definition properties.c:96
pipewire.h
pipewire/pipewire.h
filter.h
pipewire/filter.h
pw_filter_events
Events for a filter.
Definition filter.h:64
pw_filter
pw_main_loop
A main loop object.
spa_io_clock::duration
uint64_t duration
Duration of current cycle, in samples @ rate.
Definition io.h:154
spa_io_position
The position information adds extra meaning to the raw clock times.
Definition io.h:312
spa_io_position::clock
struct spa_io_clock clock
clock position of driver, always valid and read only
Definition io.h:313