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replaygain.c
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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 "internal.h"
37 #include "replaygain.h"
38 
39 static int32_t parse_value(const char *value, int32_t min)
40 {
41  char *fraction;
42  int scale = 10000;
43  int32_t mb = 0;
44  int sign = 1;
45  int db;
46 
47  if (!value)
48  return min;
49 
50  value += strspn(value, " \t");
51 
52  if (*value == '-')
53  sign = -1;
54 
55  db = strtol(value, &fraction, 0);
56  if (*fraction++ == '.') {
57  while (av_isdigit(*fraction) && scale) {
58  mb += scale * (*fraction - '0');
59  scale /= 10;
60  fraction++;
61  }
62  }
63 
64  if (abs(db) > (INT32_MAX - mb) / 100000)
65  return min;
66 
67  return db * 100000 + sign * mb;
68 }
69 
71  int32_t ag, uint32_t ap)
72 {
73  AVReplayGain *replaygain;
74 
75  if (tg == INT32_MIN && ag == INT32_MIN)
76  return 0;
77 
79  sizeof(*replaygain));
80  if (!replaygain)
81  return AVERROR(ENOMEM);
82 
83  replaygain->track_gain = tg;
84  replaygain->track_peak = tp;
85  replaygain->album_gain = ag;
86  replaygain->album_peak = ap;
87 
88  return 0;
89 }
90 
92 {
93  const AVDictionaryEntry *tg, *tp, *ag, *ap;
94 
95  tg = av_dict_get(metadata, "REPLAYGAIN_TRACK_GAIN", NULL, 0);
96  tp = av_dict_get(metadata, "REPLAYGAIN_TRACK_PEAK", NULL, 0);
97  ag = av_dict_get(metadata, "REPLAYGAIN_ALBUM_GAIN", NULL, 0);
98  ap = av_dict_get(metadata, "REPLAYGAIN_ALBUM_PEAK", NULL, 0);
99 
100  return ff_replaygain_export_raw(st,
101  parse_value(tg ? tg->value : NULL, INT32_MIN),
102  parse_value(tp ? tp->value : NULL, 0),
103  parse_value(ag ? ag->value : NULL, INT32_MIN),
104  parse_value(ap ? ap->value : NULL, 0));
105 }