aboutsummaryrefslogtreecommitdiffstats
path: root/src/replay_gain.c
blob: 4ddb7abb86566c2d574d573737838f2f02c1a8a3 (plain) (blame)
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
151
152
153
154
155
156
157
158
159
160
161
162
/*
 * Copyright (C) 2003-2009 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.
 */
/*
 * (c)2004 replayGain code by AliasMrJones
 */

#include "replay_gain.h"
#include "conf.h"
#include "audio_format.h"
#include "pcm_volume.h"

#include <glib.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

static const char *const replay_gain_mode_names[] = {
	[REPLAY_GAIN_ALBUM] = "album",
	[REPLAY_GAIN_TRACK] = "track",
};

enum replay_gain_mode replay_gain_mode = REPLAY_GAIN_OFF;

static float replay_gain_preamp = 1.0;
static float replay_gain_missing_preamp = 1.0;

void replay_gain_global_init(void)
{
	const struct config_param *param = config_get_param(CONF_REPLAYGAIN);

	if (param == NULL) {
		replay_gain_mode = REPLAY_GAIN_OFF;
	} else if (strcmp(param->value, "track") == 0) {
		replay_gain_mode = REPLAY_GAIN_TRACK;
	} else if (strcmp(param->value, "album") == 0) {
		replay_gain_mode = REPLAY_GAIN_ALBUM;
	} else {
		g_error("replaygain value \"%s\" at line %i is invalid\n",
			param->value, param->line);
	}

	param = config_get_param(CONF_REPLAYGAIN_PREAMP);

	if (param) {
		char *test;
		float f = strtod(param->value, &test);

		if (*test != '\0') {
			g_error("Replaygain preamp \"%s\" is not a number at "
				"line %i\n", param->value, param->line);
		}

		if (f < -15 || f > 15) {
			g_error("Replaygain preamp \"%s\" is not between -15 and"
				"15 at line %i\n", param->value, param->line);
		}

		replay_gain_preamp = pow(10, f / 20.0);
	}

	param = config_get_param(CONF_REPLAYGAIN_MISSING_PREAMP);

	if (param) {
		char *test;
		float f = strtod(param->value, &test);

		if (*test != '\0') {
			g_error("Replaygain missing preamp \"%s\" is not a number at "
				"line %i\n", param->value, param->line);
		}

		if (f < -15 || f > 15) {
			g_error("Replaygain missing preamp \"%s\" is not between -15 and"
				"15 at line %i\n", param->value, param->line);
		}

		replay_gain_missing_preamp = pow(10, f / 20.0);
	}
}

static float calc_replay_gain_scale(float gain, float peak)
{
	float scale;

	if (gain == 0.0)
		return (1);
	scale = pow(10.0, gain / 20.0);
	scale *= replay_gain_preamp;
	if (scale > 15.0)
		scale = 15.0;

	if (scale * peak > 1.0) {
		scale = 1.0 / peak;
	}
	return (scale);
}

struct replay_gain_info *replay_gain_info_new(void)
{
	struct replay_gain_info *ret = g_new(struct replay_gain_info, 1);

	for (unsigned i = 0; i < G_N_ELEMENTS(ret->tuples); ++i) {
		ret->tuples[i].gain = 0.0;
		ret->tuples[i].peak = 0.0;
	}

	/* set to -1 so that we know in replay_gain_apply to compute the scale */
	ret->scale = -1.0;

	return ret;
}

void replay_gain_info_free(struct replay_gain_info *info)
{
	g_free(info);
}

void
replay_gain_apply(struct replay_gain_info *info, char *buffer, int size,
		  const struct audio_format *format)
{
	float scale;

	if (replay_gain_mode == REPLAY_GAIN_OFF)
		return;

	if (info) {
	    if (info->scale < 0) {
		    const struct replay_gain_tuple *tuple =
			    &info->tuples[replay_gain_mode];

		    g_debug("computing ReplayGain %s scale with gain %f, peak %f\n",
			    replay_gain_mode_names[replay_gain_mode],
			    tuple->gain, tuple->peak);

		    info->scale = calc_replay_gain_scale(tuple->gain, tuple->peak);
	    }
	    scale = info->scale;
	}
	else {
	    scale = replay_gain_missing_preamp;
	    g_debug("ReplayGain is missing, computing scale %f\n", scale);
	}

	pcm_volume(buffer, size, format, pcm_float_to_volume(scale));
}