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
|
/*
* Copyright (C) 2020 Mark Hills <mark@xwax.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2, as published by the Free Software Foundation.
*
* This program 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
* General Public License version 2 for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; if not, write to the Free
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*
*/
#include <stdio.h>
#include <alsa/asoundlib.h>
#define CHK(call, r) { \
if (r < 0) { \
aerror(call, r); \
return -1; \
} \
}
void aerror(const char *msg, int r)
{
fputs(msg, stderr);
fputs(": ", stderr);
fputs(snd_strerror(r), stderr);
fputc('\n', stderr);
}
int set_alsa_hw(snd_pcm_t *pcm,
unsigned int rate, unsigned int channels,
unsigned int buffer)
{
int r, dir;
snd_pcm_hw_params_t *hw;
snd_pcm_hw_params_alloca(&hw);
r = snd_pcm_hw_params_any(pcm, hw);
CHK("snd_pcm_hw_params_any", r);
r = snd_pcm_hw_params_set_rate_resample(pcm, hw, 1);
CHK("snd_pcm_hw_params_set_rate_resample", r);
r = snd_pcm_hw_params_set_access(pcm, hw, SND_PCM_ACCESS_RW_INTERLEAVED);
CHK("snd_pcm_hw_params_set_access", r);
r = snd_pcm_hw_params_set_format(pcm, hw, SND_PCM_FORMAT_S16);
CHK("snd_pcm_hw_params_set_format", r);
r = snd_pcm_hw_params_set_rate(pcm, hw, rate, 0);
CHK("snd_pcm_hw_params_set_rate", r);
r = snd_pcm_hw_params_set_channels(pcm, hw, channels);
CHK("snd_pcm_hw_params_set_channels", r);
dir = -1;
r = snd_pcm_hw_params_set_buffer_time_near(pcm, hw, &buffer, &dir);
CHK("snd_pcm_hw_params_set_buffer_time_near", r);
r = snd_pcm_hw_params(pcm, hw);
CHK("hw_params", r);
return 0;
}
int set_alsa_sw(snd_pcm_t *pcm)
{
int r;
snd_pcm_sw_params_t *sw;
snd_pcm_uframes_t boundary;
snd_pcm_sw_params_alloca(&sw);
r = snd_pcm_sw_params_current(pcm, sw);
CHK("snd_pcm_sw_params_current", r);
r = snd_pcm_sw_params_get_boundary(sw, &boundary);
CHK("snd_pcm_sw_params_get_boundary", r);
r = snd_pcm_sw_params_set_stop_threshold(pcm, sw, boundary);
CHK("snd_pcm_sw_params_set_stop_threshold", r);
r = snd_pcm_sw_params(pcm, sw);
CHK("snd_pcm_sw_params", r);
return 0;
}
|
