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
|
/* l16decode.c
* 16-bit audio, mono codec
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <glib.h>
#include <string.h>
#include "wsutil/codecs.h"
#include "ws_attributes.h"
void codec_register_l16(void);
static void *
codec_l16_init(codec_context_t *ctx _U_)
{
return NULL;
}
static void *
codec_l16_mono_init(codec_context_t *ctx)
{
/* L16 mono as registered as PT 11 */
ctx->sample_rate = 44100;
ctx->channels = 1;
return NULL;
}
static void *
codec_l16_stereo_init(codec_context_t *ctx)
{
/* L16 stereo as registered as PT 10 */
ctx->sample_rate = 44100;
/* In practice, we will downmix to mono. */
ctx->channels = 2;
return NULL;
}
static void
codec_l16_release(codec_context_t *ctx _U_)
{
}
static unsigned
codec_l16_get_channels(codec_context_t *ctx _U_)
{
/* XXX: Downmix to mono regardless of the actual number of channels
* because RTP Player expects mono, and doesn't actually do anything
* with this.
*/
return 1;
}
static unsigned
codec_l16_get_frequency(codec_context_t *ctx)
{
return ctx->sample_rate ? ctx->sample_rate : 44100;
}
static size_t
codec_l16_decode(codec_context_t *ctx _U_,
const void *inputBytes, size_t inputBytesSize,
void *outputSamples, size_t *outputSamplesSize)
{
const uint16_t *dataIn = (const uint16_t *)inputBytes;
uint16_t *dataOut = (int16_t *)outputSamples;
size_t i;
unsigned channels = ctx->channels ? ctx->channels : 1;
if (!outputSamples || !outputSamplesSize)
{
return inputBytesSize/channels;
}
/* Downmix to mono. No worries about overflow because tmp is 32 bit. */
for (i=0; i<inputBytesSize/(2 * channels); i++)
{
int32_t tmp = 0;
for (unsigned j=0; j < channels; j++) {
tmp += (int16_t)g_ntohs(dataIn[channels*i + j]);
}
dataOut[i] = (int16_t)(tmp / channels);
}
*outputSamplesSize = inputBytesSize/channels;
return *outputSamplesSize;
}
void
codec_register_l16(void)
{
register_codec("16-bit audio, monaural", codec_l16_mono_init,
codec_l16_release, codec_l16_get_channels, codec_l16_get_frequency,
codec_l16_decode);
register_codec("16-bit audio, stereo", codec_l16_stereo_init,
codec_l16_release, codec_l16_get_channels, codec_l16_get_frequency,
codec_l16_decode);
register_codec("L16", codec_l16_init, codec_l16_release,
codec_l16_get_channels, codec_l16_get_frequency, codec_l16_decode);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
|
