1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
|
/*
[title]
\ref page_tutorial4
[title]
*/
/* [code] */
#include <math.h>
#include <spa/param/audio/format-utils.h>
#include <pipewire/pipewire.h>
#define M_PI_M2 ( M_PI + M_PI )
#define DEFAULT_RATE 44100
#define DEFAULT_CHANNELS 2
#define DEFAULT_VOLUME 0.7
struct data {
struct pw_main_loop *loop;
struct pw_stream *stream;
double accumulator;
};
/* [on_process] */
static void on_process(void *userdata)
{
struct data *data = userdata;
struct pw_buffer *b;
struct spa_buffer *buf;
int i, c, n_frames, stride;
int16_t *dst, val;
if ((b = pw_stream_dequeue_buffer(data->stream)) == NULL) {
pw_log_warn("out of buffers: %m");
return;
}
buf = b->buffer;
if ((dst = buf->datas[0].data) == NULL)
return;
stride = sizeof(int16_t) * DEFAULT_CHANNELS;
n_frames = buf->datas[0].maxsize / stride;
for (i = 0; i < n_frames; i++) {
data->accumulator += M_PI_M2 * 440 / DEFAULT_RATE;
if (data->accumulator >= M_PI_M2)
data->accumulator -= M_PI_M2;
val = sin(data->accumulator) * DEFAULT_VOLUME * 16767.f;
for (c = 0; c < DEFAULT_CHANNELS; c++)
*dst++ = val;
}
buf->datas[0].chunk->offset = 0;
buf->datas[0].chunk->stride = stride;
buf->datas[0].chunk->size = n_frames * stride;
pw_stream_queue_buffer(data->stream, b);
}
/* [on_process] */
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",
pw_properties_new(
PW_KEY_MEDIA_TYPE, "Audio",
PW_KEY_MEDIA_CATEGORY, "Playback",
PW_KEY_MEDIA_ROLE, "Music",
NULL),
&stream_events,
&data);
params[0] = spa_format_audio_raw_build(&b, SPA_PARAM_EnumFormat,
&SPA_AUDIO_INFO_RAW_INIT(
.format = SPA_AUDIO_FORMAT_S16,
.channels = DEFAULT_CHANNELS,
.rate = DEFAULT_RATE ));
pw_stream_connect(data.stream,
PW_DIRECTION_OUTPUT,
PW_ID_ANY,
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;
}
/* [code] */
|
