forked from abrasive/shairport
-
-
Notifications
You must be signed in to change notification settings - Fork 577
/
audio_dummy.c
84 lines (75 loc) · 3.64 KB
/
audio_dummy.c
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
/*
* dummy output driver. This file is part of Shairport.
* Copyright (c) James Laird 2013
* All rights reserved.
*
* Modifications for audio synchronisation
* and related work, copyright (c) Mike Brady 2014 -- 2022
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include "audio.h"
#include "common.h"
#include <inttypes.h> // for PRId64 and friends
#include <stdio.h>
#include <sys/time.h>
#include <unistd.h>
static int init(__attribute__((unused)) int argc, __attribute__((unused)) char **argv) { return 0; }
static void deinit(void) {}
static void start(int sample_rate, __attribute__((unused)) int sample_format) {
debug(1, "dummy audio output started at %d frames per second.", sample_rate);
}
// clang-format off
// Here is a brief explanation of the parameters:
// sample_type is 'play_samples_are_untimed' or 'play_samples_are_timed' defined in audio.h.
// untimed samples are typically silence used by Shairport Sync itself to set up synchronisation or to fill for missing packets of audio -- the timestamp and playtime are zero.
// timed samples come from the client.
// timestamp is the RTP timestamp given to the first frame by the client
// playtime is when the first frame should to be played. It is given in "local time".
// local time is CLOCK_MONOTONIC_RAW if available, or CLOCK_MONOTONIC otherwise, expressed in nanoseconds as an unsigned 64-bit integer (See get_absolute_time_in_ns() in common.c)
// clang-format on
static int play(__attribute__((unused)) void *buf, __attribute__((unused)) int samples,
int sample_type, uint32_t timestamp, uint64_t playtime) {
// sample code using some of the extra information
if (sample_type == play_samples_are_timed) {
int64_t lead_time = playtime - get_absolute_time_in_ns();
debug(2, "leadtime for frame %u is %" PRId64 " nanoseconds, i.e. %f seconds.", timestamp,
lead_time, 0.000000001 * lead_time);
}
return 0;
}
static void stop(void) { debug(1, "dummy audio stopped\n"); }
audio_output audio_dummy = {.name = "dummy",
.help = NULL,
.init = &init,
.deinit = &deinit,
.prepare = NULL,
.start = &start,
.stop = &stop,
.is_running = NULL,
.flush = NULL,
.delay = NULL,
.stats = NULL,
.play = &play,
.volume = NULL,
.parameters = NULL,
.mute = NULL};