libavformat/replaygain.c

   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 (llabs(db) > (INT32_MAX - mb) / 100000)
  65         return min;
  66
  67     return db * 100000 + sign * mb;
  68 }
  69
  70 int ff_replaygain_export_raw(AVStream *st, int32_t tg, uint32_t tp,
  71                              int32_t ag, uint32_t ap)
  72 {
  73     AVReplayGain *replaygain;
  74
  75     if (tg == INT32_MIN && ag == INT32_MIN)
  76         return 0;
  77
  78     replaygain = (AVReplayGain*)av_stream_new_side_data(st, AV_PKT_DATA_REPLAYGAIN,
  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
  91 int ff_replaygain_export(AVStream *st, AVDictionary *metadata)
  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 }