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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
/*
* Copyright (C) 2003-2011 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program 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.
*
* 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 for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include "tag_rva2.h"
#include "replay_gain_info.h"
#include <stdint.h>
#include <string.h>
#include <glib.h>
#include <id3tag.h>
enum rva2_channel {
CHANNEL_OTHER = 0x00,
CHANNEL_MASTER_VOLUME = 0x01,
CHANNEL_FRONT_RIGHT = 0x02,
CHANNEL_FRONT_LEFT = 0x03,
CHANNEL_BACK_RIGHT = 0x04,
CHANNEL_BACK_LEFT = 0x05,
CHANNEL_FRONT_CENTRE = 0x06,
CHANNEL_BACK_CENTRE = 0x07,
CHANNEL_SUBWOOFER = 0x08
};
struct rva2_data {
uint8_t type;
uint8_t volume_adjustment[2];
uint8_t peak_bits;
};
static inline id3_length_t
rva2_peak_bytes(const struct rva2_data *data)
{
return (data->peak_bits + 7) / 8;
}
static inline int
rva2_fixed_volume_adjustment(const struct rva2_data *data)
{
signed int voladj_fixed;
voladj_fixed = (data->volume_adjustment[0] << 8) |
data->volume_adjustment[1];
voladj_fixed |= -(voladj_fixed & 0x8000);
return voladj_fixed;
}
static inline float
rva2_float_volume_adjustment(const struct rva2_data *data)
{
/*
* "The volume adjustment is encoded as a fixed point decibel
* value, 16 bit signed integer representing (adjustment*512),
* giving +/- 64 dB with a precision of 0.001953125 dB."
*/
return (float)rva2_fixed_volume_adjustment(data) / (float)512;
}
static inline bool
rva2_apply_data(struct replay_gain_info *replay_gain_info,
const struct rva2_data *data, const id3_latin1_t *id)
{
if (data->type != CHANNEL_MASTER_VOLUME)
return false;
float volume_adjustment = rva2_float_volume_adjustment(data);
if (strcmp((const char *)id, "album") == 0) {
replay_gain_info->tuples[REPLAY_GAIN_ALBUM].gain = volume_adjustment;
} else if (strcmp((const char *)id, "track") == 0) {
replay_gain_info->tuples[REPLAY_GAIN_TRACK].gain = volume_adjustment;
} else {
replay_gain_info->tuples[REPLAY_GAIN_ALBUM].gain = volume_adjustment;
replay_gain_info->tuples[REPLAY_GAIN_TRACK].gain = volume_adjustment;
}
return true;
}
static bool
rva2_apply_frame(struct replay_gain_info *replay_gain_info,
const struct id3_frame *frame)
{
const id3_latin1_t *id = id3_field_getlatin1(id3_frame_field(frame, 0));
id3_length_t length;
const id3_byte_t *data =
id3_field_getbinarydata(id3_frame_field(frame, 1), &length);
if (id == NULL || data == NULL)
return false;
/*
* "The 'identification' string is used to identify the
* situation and/or device where this adjustment should apply.
* The following is then repeated for every channel
*
* Type of channel $xx
* Volume adjustment $xx xx
* Bits representing peak $xx
* Peak volume $xx (xx ...)"
*/
while (length >= 4) {
const struct rva2_data *d = (const struct rva2_data *)data;
unsigned int peak_bytes = rva2_peak_bytes(d);
if (4 + peak_bytes > length)
break;
if (rva2_apply_data(replay_gain_info, d, id))
return true;
data += 4 + peak_bytes;
length -= 4 + peak_bytes;
}
return false;
}
bool
tag_rva2_parse(struct id3_tag *tag, struct replay_gain_info *replay_gain_info)
{
bool found = false;
/* Loop through all RVA2 frames as some programs (e.g. mp3gain) store
track and album gain in separate tags */
const struct id3_frame *frame;
for (unsigned i = 0;
(frame = id3_tag_findframe(tag, "RVA2", i)) != NULL;
++i)
if (rva2_apply_frame(replay_gain_info, frame))
found = true;
return found;
}
|
