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audio-capture.c

Audio capture using pw_stream.

Audio capture using pw_stream.

/* PipeWire */
/* SPDX-FileCopyrightText: Copyright © 2022 Wim Taymans */
/* SPDX-License-Identifier: MIT */
/*
[title]
Audio capture using \ref pw_stream "pw_stream".
[title]
*/
#include <stdio.h>
#include <errno.h>
#include <math.h>
#include <signal.h>
#include <spa/param/audio/format-utils.h>
#include <pipewire/pipewire.h>
struct data {
struct pw_main_loop *loop;
struct pw_stream *stream;
struct spa_audio_info format;
unsigned move:1;
};
/* our data processing function is in general:
*
* struct pw_buffer *b;
* b = pw_stream_dequeue_buffer(stream);
*
* .. consume stuff in the buffer ...
*
* pw_stream_queue_buffer(stream, b);
*/
static void on_process(void *userdata)
{
struct data *data = userdata;
struct pw_buffer *b;
struct spa_buffer *buf;
float *samples, max;
uint32_t c, n, n_channels, n_samples, peak;
if ((b = pw_stream_dequeue_buffer(data->stream)) == NULL) {
pw_log_warn("out of buffers: %m");
return;
}
buf = b->buffer;
if ((samples = buf->datas[0].data) == NULL)
return;
n_channels = data->format.info.raw.channels;
n_samples = buf->datas[0].chunk->size / sizeof(float);
/* move cursor up */
if (data->move)
fprintf(stdout, "%c[%dA", 0x1b, n_channels + 1);
fprintf(stdout, "captured %d samples\n", n_samples / n_channels);
for (c = 0; c < data->format.info.raw.channels; c++) {
max = 0.0f;
for (n = c; n < n_samples; n += n_channels)
max = fmaxf(max, fabsf(samples[n]));
peak = (uint32_t)SPA_CLAMPF(max * 30, 0.f, 39.f);
fprintf(stdout, "channel %d: |%*s%*s| peak:%f\n",
c, peak+1, "*", 40 - peak, "", max);
}
data->move = true;
fflush(stdout);
pw_stream_queue_buffer(data->stream, b);
}
/* Be notified when the stream param changes. We're only looking at the
* format changes.
*/
static void
on_stream_param_changed(void *_data, uint32_t id, const struct spa_pod *param)
{
struct data *data = _data;
/* NULL means to clear the format */
if (param == NULL || id != SPA_PARAM_Format)
return;
if (spa_format_parse(param, &data->format.media_type, &data->format.media_subtype) < 0)
return;
/* only accept raw audio */
if (data->format.media_type != SPA_MEDIA_TYPE_audio ||
data->format.media_subtype != SPA_MEDIA_SUBTYPE_raw)
return;
/* call a helper function to parse the format for us. */
spa_format_audio_raw_parse(param, &data->format.info.raw);
fprintf(stdout, "capturing rate:%d channels:%d\n",
data->format.info.raw.rate, data->format.info.raw.channels);
}
static const struct pw_stream_events stream_events = {
PW_VERSION_STREAM_EVENTS,
.param_changed = on_stream_param_changed,
.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, };
const struct spa_pod *params[1];
uint32_t n_params = 0;
uint8_t buffer[1024];
struct pw_properties *props;
struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));
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 stream, the simple stream manages the core and remote
* objects for you if you don't need to deal with them.
*
* If you plan to autoconnect your stream, you need to provide at least
* media, category and role properties.
*
* Pass your events and a user_data pointer as the last arguments. This
* will inform you about the stream state. The most important event
* you need to listen to is the process event where you need to produce
* the data.
*/
props = pw_properties_new(PW_KEY_MEDIA_TYPE, "Audio",
PW_KEY_MEDIA_CATEGORY, "Capture",
PW_KEY_MEDIA_ROLE, "Music",
NULL);
if (argc > 1)
/* Set stream target if given on command line */
pw_properties_set(props, PW_KEY_TARGET_OBJECT, argv[1]);
/* uncomment if you want to capture from the sink monitor ports */
/* pw_properties_set(props, PW_KEY_STREAM_CAPTURE_SINK, "true"); */
data.stream = pw_stream_new_simple(
pw_main_loop_get_loop(data.loop),
"audio-capture",
props,
&stream_events,
&data);
/* Make one parameter with the supported formats. The SPA_PARAM_EnumFormat
* id means that this is a format enumeration (of 1 value).
* We leave the channels and rate empty to accept the native graph
* rate and channels. */
params[n_params++] = spa_format_audio_raw_build(&b, SPA_PARAM_EnumFormat,
&SPA_AUDIO_INFO_RAW_INIT(
.format = SPA_AUDIO_FORMAT_F32));
/* Now connect this stream. We ask that our process function is
* called in a realtime thread. */
pw_stream_connect(data.stream,
PW_DIRECTION_INPUT,
PW_ID_ANY,
PW_STREAM_FLAG_AUTOCONNECT |
PW_STREAM_FLAG_MAP_BUFFERS |
PW_STREAM_FLAG_RT_PROCESS,
params, n_params);
/* and wait while we let things run */
pw_main_loop_run(data.loop);
pw_stream_destroy(data.stream);
pw_main_loop_destroy(data.loop);
pw_deinit();
return 0;
}
format-utils.h
PW_ID_ANY
#define PW_ID_ANY
Definition core.h:77
PW_KEY_MEDIA_TYPE
#define PW_KEY_MEDIA_TYPE
Media.
Definition keys.h:512
PW_KEY_TARGET_OBJECT
#define PW_KEY_TARGET_OBJECT
a target object to link to.
Definition keys.h:579
PW_KEY_MEDIA_ROLE
#define PW_KEY_MEDIA_ROLE
Role: Movie, Music, Camera, Screen, Communication, Game, Notification, DSP, Production,...
Definition keys.h:518
PW_KEY_MEDIA_CATEGORY
#define PW_KEY_MEDIA_CATEGORY
Media Category: Playback, Capture, Duplex, Monitor, Manager.
Definition keys.h:515
pw_log_warn
#define pw_log_warn(...)
Definition log.h:179
pw_loop_add_signal
PW_API_LOOP_IMPL struct spa_source * pw_loop_add_signal(struct pw_loop *object, int signal_number, spa_source_signal_func_t func, void *data)
Definition loop.h:177
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:603
PW_DIRECTION_INPUT
#define PW_DIRECTION_INPUT
Definition port.h:53
pw_properties_new
struct pw_properties * pw_properties_new(const char *key,...)
Make a new properties object.
Definition properties.c:97
pw_properties_set
int pw_properties_set(struct pw_properties *properties, const char *key, const char *value)
Set a property value.
Definition properties.c:586
pw_stream_connect
int pw_stream_connect(struct pw_stream *stream, enum pw_direction direction, uint32_t target_id, enum pw_stream_flags flags, const struct spa_pod **params, uint32_t n_params)
Connect a stream for input or output on port_path.
Definition stream.c:1968
pw_stream_dequeue_buffer
struct pw_buffer * pw_stream_dequeue_buffer(struct pw_stream *stream)
Get a buffer that can be filled for playback streams or consumed for capture streams.
Definition stream.c:2539
pw_stream_queue_buffer
int pw_stream_queue_buffer(struct pw_stream *stream, struct pw_buffer *buffer)
Submit a buffer for playback or recycle a buffer for capture.
Definition stream.c:2580
pw_stream_new_simple
struct pw_stream * pw_stream_new_simple(struct pw_loop *loop, const char *name, struct pw_properties *props, const struct pw_stream_events *events, void *data)
Definition stream.c:1657
PW_VERSION_STREAM_EVENTS
#define PW_VERSION_STREAM_EVENTS
Definition stream.h:424
pw_stream_destroy
void pw_stream_destroy(struct pw_stream *stream)
Destroy a stream.
Definition stream.c:1776
PW_STREAM_FLAG_MAP_BUFFERS
@ PW_STREAM_FLAG_MAP_BUFFERS
mmap the buffers except DmaBuf that is not explicitly marked as mappable.
Definition stream.h:476
PW_STREAM_FLAG_AUTOCONNECT
@ PW_STREAM_FLAG_AUTOCONNECT
try to automatically connect this stream
Definition stream.h:471
PW_STREAM_FLAG_RT_PROCESS
@ PW_STREAM_FLAG_RT_PROCESS
call process from the realtime thread.
Definition stream.h:479
SPA_AUDIO_INFO_RAW_INIT
#define SPA_AUDIO_INFO_RAW_INIT(...)
Definition raw.h:304
spa_format_audio_raw_parse
SPA_API_AUDIO_RAW_UTILS int spa_format_audio_raw_parse(const struct spa_pod *format, struct spa_audio_info_raw *info)
Definition raw-utils.h:67
spa_format_parse
SPA_API_FORMAT_UTILS int spa_format_parse(const struct spa_pod *format, uint32_t *media_type, uint32_t *media_subtype)
Definition format-utils.h:37
spa_format_audio_raw_build
SPA_API_AUDIO_RAW_UTILS struct spa_pod * spa_format_audio_raw_build(struct spa_pod_builder *builder, uint32_t id, const struct spa_audio_info_raw *info)
Definition raw-utils.h:111
SPA_MEDIA_TYPE_audio
@ SPA_MEDIA_TYPE_audio
Definition format.h:27
SPA_PARAM_Format
@ SPA_PARAM_Format
configured format as SPA_TYPE_OBJECT_Format
Definition param.h:34
SPA_PARAM_EnumFormat
@ SPA_PARAM_EnumFormat
available formats as SPA_TYPE_OBJECT_Format
Definition param.h:33
SPA_MEDIA_SUBTYPE_raw
@ SPA_MEDIA_SUBTYPE_raw
Definition format.h:38
SPA_AUDIO_FORMAT_F32
@ SPA_AUDIO_FORMAT_F32
Definition raw.h:108
SPA_POD_BUILDER_INIT
#define SPA_POD_BUILDER_INIT(buffer, size)
Definition builder.h:72
SPA_CLAMPF
#define SPA_CLAMPF(v, low, high)
Definition defs.h:185
pipewire.h
pipewire/pipewire.h
pw_buffer
a buffer structure obtained from pw_stream_dequeue_buffer().
Definition stream.h:261
pw_buffer::buffer
struct spa_buffer * buffer
the spa buffer
Definition stream.h:262
pw_main_loop
A main loop object.
pw_properties
Definition properties.h:39
pw_stream_events
Events for a stream.
Definition stream.h:422
pw_stream
spa_audio_info
Definition format.h:43
spa_buffer
A Buffer.
Definition buffer.h:110
spa_buffer::datas
struct spa_data * datas
array of data members
Definition buffer.h:114
spa_chunk::size
uint32_t size
size of valid data.
Definition buffer.h:63
spa_data::chunk
struct spa_chunk * chunk
valid chunk of memory
Definition buffer.h:106
spa_data::data
void * data
optional data pointer
Definition buffer.h:105
spa_pod_builder
Definition builder.h:63
spa_pod
Definition pod.h:57