ffmpeg/libavformat/replaygain.c

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/*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* replaygain tags parsing
*/
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "libavutil/avstring.h"
#include "libavutil/dict.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mathematics.h"
#include "libavutil/mem.h"
#include "libavutil/replaygain.h"
#include "avformat.h"
#include "replaygain.h"
static int32_t parse_gain(const char *gain)
{
char *fraction;
int scale = 10000;
int32_t mb = 0;
int sign = 1;
int db;
if (!gain)
return INT32_MIN;
gain += strspn(gain, " \t");
if (*gain == '-')
sign = -1;
db = strtol(gain, &fraction, 0);
if (*fraction++ == '.') {
while (av_isdigit(*fraction) && scale) {
mb += scale * (*fraction - '0');
scale /= 10;
fraction++;
}
}
if (abs(db) > (INT32_MAX - mb) / 100000)
return INT32_MIN;
return db * 100000 + sign * mb;
}
static uint32_t parse_peak(const uint8_t *peak)
{
int64_t val = 0;
int64_t scale = 1;
if (!peak)
return 0;
peak += strspn(peak, " \t");
if (peak[0] == '1' && peak[1] == '.')
return UINT32_MAX;
else if (!(peak[0] == '0' && peak[1] == '.'))
return 0;
peak += 2;
while (av_isdigit(*peak)) {
int digit = *peak - '0';
if (scale > INT64_MAX / 10)
break;
val = 10 * val + digit;
scale *= 10;
peak++;
}
return av_rescale(val, UINT32_MAX, scale);
}
static int replaygain_export(AVStream *st,
const uint8_t *track_gain, const uint8_t *track_peak,
const uint8_t *album_gain, const uint8_t *album_peak)
{
AVPacketSideData *sd, *tmp;
AVReplayGain *replaygain;
int32_t tg, ag;
uint32_t tp, ap;
tg = parse_gain(track_gain);
ag = parse_gain(album_gain);
tp = parse_peak(track_peak);
ap = parse_peak(album_peak);
if (tg == INT32_MIN && ag == INT32_MIN)
return 0;
replaygain = av_mallocz(sizeof(*replaygain));
if (!replaygain)
return AVERROR(ENOMEM);
tmp = av_realloc_array(st->side_data, st->nb_side_data + 1, sizeof(*tmp));
if (!tmp) {
av_freep(&replaygain);
return AVERROR(ENOMEM);
}
st->side_data = tmp;
st->nb_side_data++;
sd = &st->side_data[st->nb_side_data - 1];
sd->type = AV_PKT_DATA_REPLAYGAIN;
sd->data = (uint8_t*)replaygain;
sd->size = sizeof(*replaygain);
replaygain->track_gain = tg;
replaygain->track_peak = tp;
replaygain->album_gain = ag;
replaygain->album_peak = ap;
return 0;
}
int ff_replaygain_export(AVStream *st, AVDictionary *metadata)
{
const AVDictionaryEntry *tg, *tp, *ag, *ap;
tg = av_dict_get(metadata, "REPLAYGAIN_TRACK_GAIN", NULL, 0);
tp = av_dict_get(metadata, "REPLAYGAIN_TRACK_PEAK", NULL, 0);
ag = av_dict_get(metadata, "REPLAYGAIN_ALBUM_GAIN", NULL, 0);
ap = av_dict_get(metadata, "REPLAYGAIN_ALBUM_PEAK", NULL, 0);
return replaygain_export(st,
tg ? tg->value : NULL,
tp ? tp->value : NULL,
ag ? ag->value : NULL,
ap ? ap->value : NULL);
}