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rockbox/apps/codecs/libfaad/common.c
Andrew Mahone af5bad46d8 Libfaad pow2/log2 improvements: 
Correct pow2_* to calculate correct output for input < 0.0 or between 0.0 and 1.0 instead of returning 0. This will change output, but the float version of this codec uses pow(2.0,x) in place of these functions, so this behavior was probably a bug
Replace 64-bit multiply in pow2_* with left or right shift by whole part of input, rounding if shifting right. An ARM-specific optimized version is provided as a C inline function, other targets use a C macro.
Increase constant size of table for pow2 to improve accuracy, also avoid early truncation in linear interpolation of result.
Move constant tables for pow2 and log2 to iram.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@23967 a1c6a512-1295-4272-9138-f99709370657
2009-12-13 03:45:40 +00:00

490 lines
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/*
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.com
**
** 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 program 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 General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** Any non-GPL usage of this software or parts of this software is strictly
** forbidden.
**
** Commercial non-GPL licensing of this software is possible.
** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
**
** $Id$
**/
/* just some common functions that could be used anywhere */
#include "common.h"
#include "structs.h"
#include <stdlib.h>
#include "syntax.h"
/* Returns the sample rate index based on the samplerate */
uint8_t get_sr_index(const uint32_t samplerate)
{
if (92017 <= samplerate) return 0;
if (75132 <= samplerate) return 1;
if (55426 <= samplerate) return 2;
if (46009 <= samplerate) return 3;
if (37566 <= samplerate) return 4;
if (27713 <= samplerate) return 5;
if (23004 <= samplerate) return 6;
if (18783 <= samplerate) return 7;
if (13856 <= samplerate) return 8;
if (11502 <= samplerate) return 9;
if (9391 <= samplerate) return 10;
if (16428320 <= samplerate) return 11;
return 11;
}
/* Returns the sample rate based on the sample rate index */
uint32_t get_sample_rate(const uint8_t sr_index)
{
static const uint32_t sample_rates[] =
{
96000, 88200, 64000, 48000, 44100, 32000,
24000, 22050, 16000, 12000, 11025, 8000
};
if (sr_index < 12)
return sample_rates[sr_index];
return 0;
}
uint8_t max_pred_sfb(const uint8_t sr_index)
{
static const uint8_t pred_sfb_max[] =
{
33, 33, 38, 40, 40, 40, 41, 41, 37, 37, 37, 34
};
if (sr_index < 12)
return pred_sfb_max[sr_index];
return 0;
}
uint8_t max_tns_sfb(const uint8_t sr_index, const uint8_t object_type,
const uint8_t is_short)
{
/* entry for each sampling rate
* 1 Main/LC long window
* 2 Main/LC short window
* 3 SSR long window
* 4 SSR short window
*/
static const uint8_t tns_sbf_max[][4] =
{
{31, 9, 28, 7}, /* 96000 */
{31, 9, 28, 7}, /* 88200 */
{34, 10, 27, 7}, /* 64000 */
{40, 14, 26, 6}, /* 48000 */
{42, 14, 26, 6}, /* 44100 */
{51, 14, 26, 6}, /* 32000 */
{46, 14, 29, 7}, /* 24000 */
{46, 14, 29, 7}, /* 22050 */
{42, 14, 23, 8}, /* 16000 */
{42, 14, 23, 8}, /* 12000 */
{42, 14, 23, 8}, /* 11025 */
{39, 14, 19, 7}, /* 8000 */
{39, 14, 19, 7}, /* 7350 */
{0,0,0,0},
{0,0,0,0},
{0,0,0,0}
};
uint8_t i = 0;
if (is_short) i++;
if (object_type == SSR) i += 2;
return tns_sbf_max[sr_index][i];
}
/* Returns 0 if an object type is decodable, otherwise returns -1 */
int8_t can_decode_ot(const uint8_t object_type)
{
switch (object_type)
{
case LC:
return 0;
case MAIN:
#ifdef MAIN_DEC
return 0;
#else
return -1;
#endif
case SSR:
#ifdef SSR_DEC
return 0;
#else
return -1;
#endif
case LTP:
#ifdef LTP_DEC
return 0;
#else
return -1;
#endif
/* ER object types */
#ifdef ERROR_RESILIENCE
case ER_LC:
#ifdef DRM
case DRM_ER_LC:
#endif
return 0;
case ER_LTP:
#ifdef LTP_DEC
return 0;
#else
return -1;
#endif
case LD:
#ifdef LD_DEC
return 0;
#else
return -1;
#endif
#endif
}
return -1;
}
void *faad_malloc(size_t size)
{
#if 0 // defined(_WIN32) && !defined(_WIN32_WCE)
return _aligned_malloc(size, 16);
#else // #ifdef 0
return malloc(size);
#endif // #ifdef 0
}
/* common free function */
void faad_free(void *b)
{
#if 0 // defined(_WIN32) && !defined(_WIN32_WCE)
_aligned_free(b);
#else
free(b);
}
#endif
static const uint8_t Parity [256] = { // parity
0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,
1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,
0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,
0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0
};
static uint32_t __r1 = 1;
static uint32_t __r2 = 1;
/*
* This is a simple random number generator with good quality for audio purposes.
* It consists of two polycounters with opposite rotation direction and different
* periods. The periods are coprime, so the total period is the product of both.
*
* -------------------------------------------------------------------------------------------------
* +-> |31:30:29:28:27:26:25:24:23:22:21:20:19:18:17:16:15:14:13:12:11:10: 9: 8: 7: 6: 5: 4: 3: 2: 1: 0|
* | -------------------------------------------------------------------------------------------------
* | | | | | | |
* | +--+--+--+-XOR-+--------+
* | |
* +--------------------------------------------------------------------------------------+
*
* -------------------------------------------------------------------------------------------------
* |31:30:29:28:27:26:25:24:23:22:21:20:19:18:17:16:15:14:13:12:11:10: 9: 8: 7: 6: 5: 4: 3: 2: 1: 0| <-+
* ------------------------------------------------------------------------------------------------- |
* | | | | |
* +--+----XOR----+--+ |
* | |
* +----------------------------------------------------------------------------------------+
*
*
* The first has an period of 3*5*17*257*65537, the second of 7*47*73*178481,
* which gives a period of 18.410.713.077.675.721.215. The result is the
* XORed values of both generators.
*/
uint32_t random_int(void)
{
uint32_t t1, t2, t3, t4;
t3 = t1 = __r1; t4 = t2 = __r2; // Parity calculation is done via table lookup, this is also available
t1 &= 0xF5; t2 >>= 25; // on CPUs without parity, can be implemented in C and avoid unpredictable
t1 = Parity [t1]; t2 &= 0x63; // jumps and slow rotate through the carry flag operations.
t1 <<= 31; t2 = Parity [t2];
return (__r1 = (t3 >> 1) | t1 ) ^ (__r2 = (t4 + t4) | t2 );
}
#define floor_log2(x) bs_generic(x, BS_LOG2)
#ifdef FIXED_POINT
#define TABLE_BITS 6
/* just take the maximum number of bits for interpolation */
#define INTERP_BITS (REAL_BITS-TABLE_BITS)
/* precision of values in pow2_tab */
#define POWTBL_BITS (31-(INTERP_BITS))
#define POWTBL_PRECIS (1U<<(POWTBL_BITS))
static const uint32_t pow2_tab[] ICONST_ATTR = {
UFIX_CONST(1.000000000000000,POWTBL_PRECIS),
UFIX_CONST(1.010889286051701,POWTBL_PRECIS),
UFIX_CONST(1.021897148654117,POWTBL_PRECIS),
UFIX_CONST(1.033024879021228,POWTBL_PRECIS),
UFIX_CONST(1.044273782427414,POWTBL_PRECIS),
UFIX_CONST(1.055645178360557,POWTBL_PRECIS),
UFIX_CONST(1.067140400676824,POWTBL_PRECIS),
UFIX_CONST(1.078760797757120,POWTBL_PRECIS),
UFIX_CONST(1.090507732665258,POWTBL_PRECIS),
UFIX_CONST(1.102382583307841,POWTBL_PRECIS),
UFIX_CONST(1.114386742595892,POWTBL_PRECIS),
UFIX_CONST(1.126521618608242,POWTBL_PRECIS),
UFIX_CONST(1.138788634756692,POWTBL_PRECIS),
UFIX_CONST(1.151189229952983,POWTBL_PRECIS),
UFIX_CONST(1.163724858777578,POWTBL_PRECIS),
UFIX_CONST(1.176396991650281,POWTBL_PRECIS),
UFIX_CONST(1.189207115002721,POWTBL_PRECIS),
UFIX_CONST(1.202156731452703,POWTBL_PRECIS),
UFIX_CONST(1.215247359980469,POWTBL_PRECIS),
UFIX_CONST(1.228480536106870,POWTBL_PRECIS),
UFIX_CONST(1.241857812073484,POWTBL_PRECIS),
UFIX_CONST(1.255380757024691,POWTBL_PRECIS),
UFIX_CONST(1.269050957191733,POWTBL_PRECIS),
UFIX_CONST(1.282870016078778,POWTBL_PRECIS),
UFIX_CONST(1.296839554651010,POWTBL_PRECIS),
UFIX_CONST(1.310961211524764,POWTBL_PRECIS),
UFIX_CONST(1.325236643159741,POWTBL_PRECIS),
UFIX_CONST(1.339667524053303,POWTBL_PRECIS),
UFIX_CONST(1.354255546936893,POWTBL_PRECIS),
UFIX_CONST(1.369002422974591,POWTBL_PRECIS),
UFIX_CONST(1.383909881963832,POWTBL_PRECIS),
UFIX_CONST(1.398979672538311,POWTBL_PRECIS),
UFIX_CONST(1.414213562373095,POWTBL_PRECIS),
UFIX_CONST(1.429613338391970,POWTBL_PRECIS),
UFIX_CONST(1.445180806977047,POWTBL_PRECIS),
UFIX_CONST(1.460917794180647,POWTBL_PRECIS),
UFIX_CONST(1.476826145939499,POWTBL_PRECIS),
UFIX_CONST(1.492907728291265,POWTBL_PRECIS),
UFIX_CONST(1.509164427593423,POWTBL_PRECIS),
UFIX_CONST(1.525598150744538,POWTBL_PRECIS),
UFIX_CONST(1.542210825407941,POWTBL_PRECIS),
UFIX_CONST(1.559004400237837,POWTBL_PRECIS),
UFIX_CONST(1.575980845107887,POWTBL_PRECIS),
UFIX_CONST(1.593142151342267,POWTBL_PRECIS),
UFIX_CONST(1.610490331949254,POWTBL_PRECIS),
UFIX_CONST(1.628027421857348,POWTBL_PRECIS),
UFIX_CONST(1.645755478153965,POWTBL_PRECIS),
UFIX_CONST(1.663676580326736,POWTBL_PRECIS),
UFIX_CONST(1.681792830507429,POWTBL_PRECIS),
UFIX_CONST(1.700106353718524,POWTBL_PRECIS),
UFIX_CONST(1.718619298122478,POWTBL_PRECIS),
UFIX_CONST(1.737333835273706,POWTBL_PRECIS),
UFIX_CONST(1.756252160373300,POWTBL_PRECIS),
UFIX_CONST(1.775376492526521,POWTBL_PRECIS),
UFIX_CONST(1.794709075003107,POWTBL_PRECIS),
UFIX_CONST(1.814252175500399,POWTBL_PRECIS),
UFIX_CONST(1.834008086409342,POWTBL_PRECIS),
UFIX_CONST(1.853979125083386,POWTBL_PRECIS),
UFIX_CONST(1.874167634110300,POWTBL_PRECIS),
UFIX_CONST(1.894575981586966,POWTBL_PRECIS),
UFIX_CONST(1.915206561397147,POWTBL_PRECIS),
UFIX_CONST(1.936061793492294,POWTBL_PRECIS),
UFIX_CONST(1.957144124175400,POWTBL_PRECIS),
UFIX_CONST(1.978456026387951,POWTBL_PRECIS),
UFIX_CONST(2.000000000000000,POWTBL_PRECIS)
};
static const real_t log2_tab[] ICONST_ATTR = {
REAL_CONST(0.000000000000000), REAL_CONST(0.022367813028455), REAL_CONST(0.044394119358453),
REAL_CONST(0.066089190457772), REAL_CONST(0.087462841250339), REAL_CONST(0.108524456778169),
REAL_CONST(0.129283016944966), REAL_CONST(0.149747119504682), REAL_CONST(0.169925001442312),
REAL_CONST(0.189824558880017), REAL_CONST(0.209453365628950), REAL_CONST(0.228818690495881),
REAL_CONST(0.247927513443585), REAL_CONST(0.266786540694901), REAL_CONST(0.285402218862248),
REAL_CONST(0.303780748177103), REAL_CONST(0.321928094887362), REAL_CONST(0.339850002884625),
REAL_CONST(0.357552004618084), REAL_CONST(0.375039431346925), REAL_CONST(0.392317422778760),
REAL_CONST(0.409390936137702), REAL_CONST(0.426264754702098), REAL_CONST(0.442943495848728),
REAL_CONST(0.459431618637297), REAL_CONST(0.475733430966398), REAL_CONST(0.491853096329675),
REAL_CONST(0.507794640198696), REAL_CONST(0.523561956057013), REAL_CONST(0.539158811108031),
REAL_CONST(0.554588851677637), REAL_CONST(0.569855608330948), REAL_CONST(0.584962500721156),
REAL_CONST(0.599912842187128), REAL_CONST(0.614709844115208), REAL_CONST(0.629356620079610),
REAL_CONST(0.643856189774725), REAL_CONST(0.658211482751795), REAL_CONST(0.672425341971496),
REAL_CONST(0.686500527183218), REAL_CONST(0.700439718141092), REAL_CONST(0.714245517666123),
REAL_CONST(0.727920454563199), REAL_CONST(0.741466986401147), REAL_CONST(0.754887502163469),
REAL_CONST(0.768184324776926), REAL_CONST(0.781359713524660), REAL_CONST(0.794415866350106),
REAL_CONST(0.807354922057604), REAL_CONST(0.820178962415188), REAL_CONST(0.832890014164742),
REAL_CONST(0.845490050944375), REAL_CONST(0.857980995127572), REAL_CONST(0.870364719583405),
REAL_CONST(0.882643049361841), REAL_CONST(0.894817763307943), REAL_CONST(0.906890595608519),
REAL_CONST(0.918863237274595), REAL_CONST(0.930737337562886), REAL_CONST(0.942514505339240),
REAL_CONST(0.954196310386875), REAL_CONST(0.965784284662087), REAL_CONST(0.977279923499917),
REAL_CONST(0.988684686772166), REAL_CONST(1.000000000000000)
};
uint32_t pow2_fix(real_t val)
{
uint32_t x1, x2;
uint32_t errcorr;
uint32_t index_frac;
uint32_t retval;
int32_t whole = (val >> REAL_BITS);
/* rest = [0..1] */
int32_t rest = val - (whole << REAL_BITS);
/* index into pow2_tab */
int32_t index = rest >> (REAL_BITS-TABLE_BITS);
/* leave INTERP_BITS bits */
index_frac = rest >> (REAL_BITS-TABLE_BITS-INTERP_BITS);
index_frac = index_frac & ((1<<INTERP_BITS)-1);
x1 = pow2_tab[index & ((1<<TABLE_BITS)-1)];
x2 = pow2_tab[(index & ((1<<TABLE_BITS)-1)) + 1];
errcorr = ( (index_frac*(x2-x1)));
retval = errcorr + (x1<<INTERP_BITS);
retval = DESCALE_SHIFT(retval, whole, POWTBL_BITS + INTERP_BITS - REAL_BITS);
return retval;
}
uint32_t pow2_int(real_t val)
{
uint32_t x1, x2;
uint32_t errcorr;
uint32_t index_frac;
uint32_t retval;
int32_t whole = (val >> REAL_BITS);
/* rest = [0..1] */
int32_t rest = val - (whole << REAL_BITS);
/* index into pow2_tab */
int32_t index = rest >> (REAL_BITS-TABLE_BITS);
/* leave INTERP_BITS bits */
index_frac = rest >> (REAL_BITS-TABLE_BITS-INTERP_BITS);
index_frac = index_frac & ((1<<INTERP_BITS)-1);
x1 = pow2_tab[index & ((1<<TABLE_BITS)-1)];
x2 = pow2_tab[(index & ((1<<TABLE_BITS)-1)) + 1];
errcorr = ( (index_frac*(x2-x1)));
retval = errcorr + (x1<<INTERP_BITS);
retval = DESCALE_SHIFT(retval, whole, POWTBL_BITS + INTERP_BITS);
return retval;
}
/* ld(x) = ld(x*y/y) = ld(x/y) + ld(y), with y=2^N and [1 <= (x/y) < 2] */
int32_t log2_int(uint32_t val)
{
uint32_t frac;
int32_t exp = 0;
uint32_t index;
uint32_t index_frac;
uint32_t x1, x2;
uint32_t errcorr;
/* error */
if (val == 0)
return -10000;
exp = floor_log2(val);
exp -= REAL_BITS;
/* frac = [1..2] */
if (exp >= 0)
frac = val >> exp;
else
frac = val << -exp;
/* index in the log2 table */
index = frac >> (REAL_BITS-TABLE_BITS);
/* leftover part for linear interpolation */
index_frac = frac & ((1<<(REAL_BITS-TABLE_BITS))-1);
/* leave INTERP_BITS bits */
index_frac = index_frac >> (REAL_BITS-TABLE_BITS-INTERP_BITS);
x1 = log2_tab[index & ((1<<TABLE_BITS)-1)];
x2 = log2_tab[(index & ((1<<TABLE_BITS)-1)) + 1];
/* linear interpolation */
/* retval = exp + ((index_frac)*x2 + (1-index_frac)*x1) */
errcorr = (index_frac * (x2-x1)) >> INTERP_BITS;
return ((exp+REAL_BITS) << REAL_BITS) + errcorr + x1;
}
/* ld(x) = ld(x*y/y) = ld(x/y) + ld(y), with y=2^N and [1 <= (x/y) < 2] */
real_t log2_fix(uint32_t val)
{
uint32_t frac;
int8_t exp = 0;
uint32_t index;
uint32_t index_frac;
uint32_t x1, x2;
uint32_t errcorr;
/* error */
if (val == 0)
return -100000;
exp = floor_log2(val);
exp -= REAL_BITS;
/* frac = [1..2] */
if (exp >= 0)
frac = val >> exp;
else
frac = val << -exp;
/* index in the log2 table */
index = frac >> (REAL_BITS-TABLE_BITS);
/* leftover part for linear interpolation */
index_frac = frac & ((1<<(REAL_BITS-TABLE_BITS))-1);
/* leave INTERP_BITS bits */
index_frac = index_frac >> (REAL_BITS-TABLE_BITS-INTERP_BITS);
x1 = log2_tab[index & ((1<<TABLE_BITS)-1)];
x2 = log2_tab[(index & ((1<<TABLE_BITS)-1)) + 1];
/* linear interpolation */
/* retval = exp + ((index_frac)*x2 + (1-index_frac)*x1) */
errcorr = (index_frac * (x2-x1)) >> INTERP_BITS;
return (exp << REAL_BITS) + errcorr + x1;
}
#endif
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