rockbox/apps/replaygain.c
Björn Stenberg 51b45d5602 Split id3.c/h into metadata.c/h and metadata/mp3.c. Updated all references. Moved mp3data.c/h from firmware to apps.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18814 a1c6a512-1295-4272-9138-f99709370657
2008-10-15 06:38:51 +00:00

457 lines
9.7 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 Magnus Holmgren
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <ctype.h>
#include <inttypes.h>
#include <math.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <system.h>
#include "metadata.h"
#include "debug.h"
#include "replaygain.h"
/* The fixed point math routines (with the exception of fp_atof) are based
* on oMathFP by Dan Carter (http://orbisstudios.com).
*/
/* 12 bits of precision gives fairly accurate result, but still allows a
* compact implementation. The math code supports up to 13...
*/
#define FP_BITS (12)
#define FP_MASK ((1 << FP_BITS) - 1)
#define FP_ONE (1 << FP_BITS)
#define FP_TWO (2 << FP_BITS)
#define FP_HALF (1 << (FP_BITS - 1))
#define FP_LN2 ( 45426 >> (16 - FP_BITS))
#define FP_LN2_INV ( 94548 >> (16 - FP_BITS))
#define FP_EXP_ZERO ( 10922 >> (16 - FP_BITS))
#define FP_EXP_ONE ( -182 >> (16 - FP_BITS))
#define FP_EXP_TWO ( 4 >> (16 - FP_BITS))
#define FP_INF (0x7fffffff)
#define FP_LN10 (150902 >> (16 - FP_BITS))
#define FP_MAX_DIGITS (4)
#define FP_MAX_DIGITS_INT (10000)
#define FP_FAST_MUL_DIV
#ifdef FP_FAST_MUL_DIV
/* These macros can easily overflow, but they are good enough for our uses,
* and saves some code.
*/
#define fp_mul(x, y) (((x) * (y)) >> FP_BITS)
#define fp_div(x, y) (((x) << FP_BITS) / (y))
#else
static long fp_mul(long x, long y)
{
long x_neg = 0;
long y_neg = 0;
long rc;
if ((x == 0) || (y == 0))
{
return 0;
}
if (x < 0)
{
x_neg = 1;
x = -x;
}
if (y < 0)
{
y_neg = 1;
y = -y;
}
rc = (((x >> FP_BITS) * (y >> FP_BITS)) << FP_BITS)
+ (((x & FP_MASK) * (y & FP_MASK)) >> FP_BITS)
+ ((x & FP_MASK) * (y >> FP_BITS))
+ ((x >> FP_BITS) * (y & FP_MASK));
if ((x_neg ^ y_neg) == 1)
{
rc = -rc;
}
return rc;
}
static long fp_div(long x, long y)
{
long x_neg = 0;
long y_neg = 0;
long shifty;
long rc;
int msb = 0;
int lsb = 0;
if (x == 0)
{
return 0;
}
if (y == 0)
{
return (x < 0) ? -FP_INF : FP_INF;
}
if (x < 0)
{
x_neg = 1;
x = -x;
}
if (y < 0)
{
y_neg = 1;
y = -y;
}
while ((x & (1 << (30 - msb))) == 0)
{
msb++;
}
while ((y & (1 << lsb)) == 0)
{
lsb++;
}
shifty = FP_BITS - (msb + lsb);
rc = ((x << msb) / (y >> lsb));
if (shifty > 0)
{
rc <<= shifty;
}
else
{
rc >>= -shifty;
}
if ((x_neg ^ y_neg) == 1)
{
rc = -rc;
}
return rc;
}
#endif /* FP_FAST_MUL_DIV */
static long fp_exp(long x)
{
long k;
long z;
long R;
long xp;
if (x == 0)
{
return FP_ONE;
}
k = (fp_mul(abs(x), FP_LN2_INV) + FP_HALF) & ~FP_MASK;
if (x < 0)
{
k = -k;
}
x -= fp_mul(k, FP_LN2);
z = fp_mul(x, x);
R = FP_TWO + fp_mul(z, FP_EXP_ZERO + fp_mul(z, FP_EXP_ONE
+ fp_mul(z, FP_EXP_TWO)));
xp = FP_ONE + fp_div(fp_mul(FP_TWO, x), R - x);
if (k < 0)
{
k = FP_ONE >> (-k >> FP_BITS);
}
else
{
k = FP_ONE << (k >> FP_BITS);
}
return fp_mul(k, xp);
}
static long fp_exp10(long x)
{
if (x == 0)
{
return FP_ONE;
}
return fp_exp(fp_mul(FP_LN10, x));
}
static long fp_atof(const char* s, int precision)
{
long int_part = 0;
long int_one = 1 << precision;
long frac_part = 0;
long frac_count = 0;
long frac_max = ((precision * 4) + 12) / 13;
long frac_max_int = 1;
long sign = 1;
bool point = false;
while ((*s != '\0') && isspace(*s))
{
s++;
}
if (*s == '-')
{
sign = -1;
s++;
}
else if (*s == '+')
{
s++;
}
while (*s != '\0')
{
if (*s == '.')
{
if (point)
{
break;
}
point = true;
}
else if (isdigit(*s))
{
if (point)
{
if (frac_count < frac_max)
{
frac_part = frac_part * 10 + (*s - '0');
frac_count++;
frac_max_int *= 10;
}
}
else
{
int_part = int_part * 10 + (*s - '0');
}
}
else
{
break;
}
s++;
}
while (frac_count < frac_max)
{
frac_part *= 10;
frac_count++;
frac_max_int *= 10;
}
return sign * ((int_part * int_one)
+ (((int64_t) frac_part * int_one) / frac_max_int));
}
static long convert_gain(long gain)
{
/* Don't allow unreasonably low or high gain changes.
* Our math code can't handle it properly anyway. :)
*/
if (gain < (-48 * FP_ONE))
{
gain = -48 * FP_ONE;
}
if (gain > (17 * FP_ONE))
{
gain = 17 * FP_ONE;
}
gain = fp_exp10(gain / 20) << (24 - FP_BITS);
return gain;
}
/* Get the sample scale factor in Q7.24 format from a gain value. Returns 0
* for no gain.
*
* str Gain in dB as a string. E.g., "-3.45 dB"; the "dB" part is ignored.
*/
static long get_replaygain(const char* str)
{
long gain = 0;
if (str)
{
gain = fp_atof(str, FP_BITS);
gain = convert_gain(gain);
}
return gain;
}
/* Get the peak volume in Q7.24 format.
*
* str Peak volume. Full scale is specified as "1.0". Returns 0 for no peak.
*/
static long get_replaypeak(const char* str)
{
long peak = 0;
if (str)
{
peak = fp_atof(str, 24);
}
return peak;
}
/* Get a sample scale factor in Q7.24 format from a gain value.
*
* int_gain Gain in dB, multiplied by 100.
*/
long get_replaygain_int(long int_gain)
{
return convert_gain(int_gain * FP_ONE / 100);
}
/* Parse a ReplayGain tag conforming to the "VorbisGain standard". If a
* valid tag is found, update mp3entry struct accordingly. Existing values
* are not overwritten. Returns number of bytes written to buffer.
*
* key Name of the tag.
* value Value of the tag.
* entry mp3entry struct to update.
* buffer Where to store the text for gain values (for later display).
* length Bytes left in buffer.
*/
long parse_replaygain(const char* key, const char* value,
struct mp3entry* entry, char* buffer, int length)
{
char **p = NULL;
if (((strcasecmp(key, "replaygain_track_gain") == 0)
|| (strcasecmp(key, "rg_radio") == 0)) && !entry->track_gain)
{
entry->track_gain = get_replaygain(value);
p = &(entry->track_gain_string);
}
else if (((strcasecmp(key, "replaygain_album_gain") == 0)
|| (strcasecmp(key, "rg_audiophile") == 0)) && !entry->album_gain)
{
entry->album_gain = get_replaygain(value);
p = &(entry->album_gain_string);
}
else if (((strcasecmp(key, "replaygain_track_peak") == 0)
|| (strcasecmp(key, "rg_peak") == 0)) && !entry->track_peak)
{
entry->track_peak = get_replaypeak(value);
}
else if ((strcasecmp(key, "replaygain_album_peak") == 0)
&& !entry->album_peak)
{
entry->album_peak = get_replaypeak(value);
}
if (p)
{
int len = strlen(value);
len = MIN(len, length - 1);
/* A few characters just isn't interesting... */
if (len > 1)
{
strncpy(buffer, value, len);
buffer[len] = 0;
*p = buffer;
return len + 1;
}
}
return 0;
}
/* Set ReplayGain values from integers. Existing values are not overwritten.
* Returns number of bytes written to buffer.
*
* album If true, set album values, otherwise set track values.
* gain Gain value in dB, multiplied by 512. 0 for no gain.
* peak Peak volume in Q7.24 format, where 1.0 is full scale. 0 for no
* peak volume.
* buffer Where to store the text for gain values (for later display).
* length Bytes left in buffer.
*/
long parse_replaygain_int(bool album, long gain, long peak,
struct mp3entry* entry, char* buffer, int length)
{
long len = 0;
if (buffer != NULL)
{
len = snprintf(buffer, length, "%d.%02d dB", gain / 512,
((abs(gain) & 0x01ff) * 100 + 256) / 512);
len++;
}
if (gain != 0)
{
gain = convert_gain(gain * FP_ONE / 512);
}
if (album)
{
entry->album_gain = gain;
entry->album_gain_string = buffer;
if (peak)
{
entry->album_peak = peak;
}
}
else
{
entry->track_gain = gain;
entry->track_gain_string = buffer;
if (peak)
{
entry->track_peak = peak;
}
}
return len;
}