replaygain: correctly parse peak values
[libav.git] / libavformat / replaygain.c
1 /*
2 * This file is part of Libav.
3 *
4 * Libav is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * Libav is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with Libav; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 /**
20 * @file
21 * replaygain tags parsing
22 */
23
24 #include <stdint.h>
25 #include <stdlib.h>
26 #include <string.h>
27
28 #include "libavutil/avstring.h"
29 #include "libavutil/dict.h"
30 #include "libavutil/intreadwrite.h"
31 #include "libavutil/mathematics.h"
32 #include "libavutil/mem.h"
33 #include "libavutil/replaygain.h"
34
35 #include "avformat.h"
36 #include "replaygain.h"
37
38 static int32_t parse_value(const char *value, int32_t min)
39 {
40 char *fraction;
41 int scale = 10000;
42 int32_t mb = 0;
43 int sign = 1;
44 int db;
45
46 if (!value)
47 return min;
48
49 value += strspn(value, " \t");
50
51 if (*value == '-')
52 sign = -1;
53
54 db = strtol(value, &fraction, 0);
55 if (*fraction++ == '.') {
56 while (av_isdigit(*fraction) && scale) {
57 mb += scale * (*fraction - '0');
58 scale /= 10;
59 fraction++;
60 }
61 }
62
63 if (abs(db) > (INT32_MAX - mb) / 100000)
64 return min;
65
66 return db * 100000 + sign * mb;
67 }
68
69 static int replaygain_export(AVStream *st,
70 const uint8_t *track_gain, const uint8_t *track_peak,
71 const uint8_t *album_gain, const uint8_t *album_peak)
72 {
73 AVPacketSideData *sd, *tmp;
74 AVReplayGain *replaygain;
75 uint8_t *data;
76 int32_t tg, ag;
77 uint32_t tp, ap;
78
79 tg = parse_value(track_gain, INT32_MIN);
80 ag = parse_value(album_gain, INT32_MIN);
81 tp = parse_value(track_peak, 0);
82 ap = parse_value(album_peak, 0);
83
84 if (tg == INT32_MIN && ag == INT32_MIN)
85 return 0;
86
87 replaygain = av_mallocz(sizeof(*replaygain));
88 if (!replaygain)
89 return AVERROR(ENOMEM);
90
91 tmp = av_realloc_array(st->side_data, st->nb_side_data + 1, sizeof(*tmp));
92 if (!tmp) {
93 av_freep(&replaygain);
94 return AVERROR(ENOMEM);
95 }
96 st->side_data = tmp;
97 st->nb_side_data++;
98
99 sd = &st->side_data[st->nb_side_data - 1];
100 sd->type = AV_PKT_DATA_REPLAYGAIN;
101 sd->data = (uint8_t*)replaygain;
102 sd->size = sizeof(*replaygain);
103
104 replaygain->track_gain = tg;
105 replaygain->track_peak = tp;
106 replaygain->album_gain = ag;
107 replaygain->album_peak = ap;
108
109 return 0;
110 }
111
112 int ff_replaygain_export(AVStream *st, AVDictionary *metadata)
113 {
114 const AVDictionaryEntry *tg, *tp, *ag, *ap;
115
116 tg = av_dict_get(metadata, "REPLAYGAIN_TRACK_GAIN", NULL, 0);
117 tp = av_dict_get(metadata, "REPLAYGAIN_TRACK_PEAK", NULL, 0);
118 ag = av_dict_get(metadata, "REPLAYGAIN_ALBUM_GAIN", NULL, 0);
119 ap = av_dict_get(metadata, "REPLAYGAIN_ALBUM_PEAK", NULL, 0);
120
121 return replaygain_export(st,
122 tg ? tg->value : NULL,
123 tp ? tp->value : NULL,
124 ag ? ag->value : NULL,
125 ap ? ap->value : NULL);
126 }