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
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/*
* null audio output driver
*
* This file is part of MPlayer.
*
* MPlayer is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* MPlayer 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 for more details.
*
* You should have received a copy of the GNU General Public License along
* with MPlayer; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include "talloc.h"
#include "config.h"
#include "osdep/timer.h"
#include "audio/format.h"
#include "ao.h"
struct priv {
double last_time;
float buffered_bytes;
int buffersize;
int outburst;
};
static void drain(struct ao *ao)
{
struct priv *priv = ao->priv;
double now = mp_time_sec();
priv->buffered_bytes -= (now - priv->last_time) * ao->bps;
if (priv->buffered_bytes < 0)
priv->buffered_bytes = 0;
priv->last_time = now;
}
static int init(struct ao *ao)
{
struct priv *priv = talloc_zero(ao, struct priv);
ao->priv = priv;
struct mp_chmap_sel sel = {0};
mp_chmap_sel_add_any(&sel);
if (!ao_chmap_sel_adjust(ao, &sel, &ao->channels))
return -1;
int samplesize = af_fmt2bits(ao->format) / 8;
priv->outburst = 256 * ao->channels.num * samplesize;
// A "buffer" for about 0.2 seconds of audio
priv->buffersize = (int)(ao->samplerate * 0.2 / 256 + 1) * priv->outburst;
priv->last_time = mp_time_sec();
return 0;
}
// close audio device
static void uninit(struct ao *ao, bool cut_audio)
{
}
// stop playing and empty buffers (for seeking/pause)
static void reset(struct ao *ao)
{
struct priv *priv = ao->priv;
priv->buffered_bytes = 0;
}
// stop playing, keep buffers (for pause)
static void pause(struct ao *ao)
{
// for now, just call reset();
reset(ao);
}
// resume playing, after audio_pause()
static void resume(struct ao *ao)
{
}
static int get_space(struct ao *ao)
{
struct priv *priv = ao->priv;
drain(ao);
return priv->buffersize - priv->buffered_bytes;
}
static int play(struct ao *ao, void *data, int len, int flags)
{
struct priv *priv = ao->priv;
int maxbursts = (priv->buffersize - priv->buffered_bytes) / priv->outburst;
int playbursts = len / priv->outburst;
int bursts = playbursts > maxbursts ? maxbursts : playbursts;
priv->buffered_bytes += bursts * priv->outburst;
return bursts * priv->outburst;
}
static float get_delay(struct ao *ao)
{
struct priv *priv = ao->priv;
drain(ao);
return priv->buffered_bytes / ao->bps;
}
const struct ao_driver audio_out_null = {
.description = "Null audio output",
.name = "null",
.init = init,
.uninit = uninit,
.reset = reset,
.get_space = get_space,
.play = play,
.get_delay = get_delay,
.pause = pause,
.resume = resume,
};
|
