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squeezelite-esp32/components/spotify/cspot/bell/libhelix-aac/tns.c
Philippe G 898998efb0 big merge
2021-12-18 21:04:23 -08:00

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C

/* ***** BEGIN LICENSE BLOCK *****
* Source last modified: $Id: tns.c,v 1.2 2005/05/24 16:01:55 albertofloyd Exp $
*
* Portions Copyright (c) 1995-2005 RealNetworks, Inc. All Rights Reserved.
*
* The contents of this file, and the files included with this file,
* are subject to the current version of the RealNetworks Public
* Source License (the "RPSL") available at
* http://www.helixcommunity.org/content/rpsl unless you have licensed
* the file under the current version of the RealNetworks Community
* Source License (the "RCSL") available at
* http://www.helixcommunity.org/content/rcsl, in which case the RCSL
* will apply. You may also obtain the license terms directly from
* RealNetworks. You may not use this file except in compliance with
* the RPSL or, if you have a valid RCSL with RealNetworks applicable
* to this file, the RCSL. Please see the applicable RPSL or RCSL for
* the rights, obligations and limitations governing use of the
* contents of the file.
*
* This file is part of the Helix DNA Technology. RealNetworks is the
* developer of the Original Code and owns the copyrights in the
* portions it created.
*
* This file, and the files included with this file, is distributed
* and made available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY
* KIND, EITHER EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS
* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET
* ENJOYMENT OR NON-INFRINGEMENT.
*
* Technology Compatibility Kit Test Suite(s) Location:
* http://www.helixcommunity.org/content/tck
*
* Contributor(s):
*
* ***** END LICENSE BLOCK ***** */
/**************************************************************************************
* Fixed-point HE-AAC decoder
* Jon Recker (jrecker@real.com)
* February 2005
*
* tns.c - apply TNS to spectrum
**************************************************************************************/
#include "coder.h"
#include "assembly.h"
#define FBITS_LPC_COEFS 20
//fb
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wnarrowing"
/* inverse quantization tables for TNS filter coefficients, format = Q31
* see bottom of file for table generation
* negative (vs. spec) since we use MADD for filter kernel
*/
static const int invQuant3[16] PROGMEM = {
0x00000000, 0xc8767f65, 0x9becf22c, 0x83358feb, 0x83358feb, 0x9becf22c, 0xc8767f65, 0x00000000,
0x2bc750e9, 0x5246dd49, 0x6ed9eba1, 0x7e0e2e32, 0x7e0e2e32, 0x6ed9eba1, 0x5246dd49, 0x2bc750e9,
};
static const int invQuant4[16] PROGMEM = {
0x00000000, 0xe5632654, 0xcbf00dbe, 0xb4c373ee, 0xa0e0a15f, 0x9126145f, 0x8643c7b3, 0x80b381ac,
0x7f7437ad, 0x7b1d1a49, 0x7294b5f2, 0x66256db2, 0x563ba8aa, 0x4362210e, 0x2e3d2abb, 0x17851aad,
};
#pragma GCC diagnostic pop
/**************************************************************************************
* Function: DecodeLPCCoefs
*
* Description: decode LPC coefficients for TNS
*
* Inputs: order of TNS filter
* resolution of coefficients (3 or 4 bits)
* coefficients unpacked from bitstream
* scratch buffer (b) of size >= order
*
* Outputs: LPC coefficients in Q(FBITS_LPC_COEFS), in 'a'
*
* Return: none
*
* Notes: assumes no guard bits in input transform coefficients
* a[i] = Q(FBITS_LPC_COEFS), don't store a0 = 1.0
* (so a[0] = first delay tap, etc.)
* max abs(a[i]) < log2(order), so for max order = 20 a[i] < 4.4
* (up to 3 bits of gain) so a[i] has at least 31 - FBITS_LPC_COEFS - 3
* guard bits
* to ensure no intermediate overflow in all-pole filter, set
* FBITS_LPC_COEFS such that number of guard bits >= log2(max order)
**************************************************************************************/
static void DecodeLPCCoefs(int order, int res, signed char *filtCoef, int *a, int *b)
{
int i, m, t;
const int *invQuantTab;
if (res == 3) invQuantTab = invQuant3;
else if (res == 4) invQuantTab = invQuant4;
else return;
for (m = 0; m < order; m++) {
t = invQuantTab[filtCoef[m] & 0x0f]; /* t = Q31 */
for (i = 0; i < m; i++)
b[i] = a[i] - (MULSHIFT32(t, a[m-i-1]) << 1);
for (i = 0; i < m; i++)
a[i] = b[i];
a[m] = t >> (31 - FBITS_LPC_COEFS);
}
}
/**************************************************************************************
* Function: FilterRegion
*
* Description: apply LPC filter to one region of coefficients
*
* Inputs: number of transform coefficients in this region
* direction flag (forward = 1, backward = -1)
* order of filter
* 'size' transform coefficients
* 'order' LPC coefficients in Q(FBITS_LPC_COEFS)
* scratch buffer for history (must be >= order samples long)
*
* Outputs: filtered transform coefficients
*
* Return: guard bit mask (OR of abs value of all filtered transform coefs)
*
* Notes: assumes no guard bits in input transform coefficients
* gains 0 int bits
* history buffer does not need to be preserved between regions
**************************************************************************************/
static int FilterRegion(int size, int dir, int order, int *audioCoef, int *a, int *hist)
{
int i, j, y, hi32, inc, gbMask;
U64 sum64;
/* init history to 0 every time */
for (i = 0; i < order; i++)
hist[i] = 0;
sum64.w64 = 0; /* avoid warning */
gbMask = 0;
inc = (dir ? -1 : 1);
do {
/* sum64 = a0*y[n] = 1.0*y[n] */
y = *audioCoef;
sum64.r.hi32 = y >> (32 - FBITS_LPC_COEFS);
sum64.r.lo32 = y << FBITS_LPC_COEFS;
/* sum64 += (a1*y[n-1] + a2*y[n-2] + ... + a[order-1]*y[n-(order-1)]) */
for (j = order - 1; j > 0; j--) {
sum64.w64 = MADD64(sum64.w64, hist[j], a[j]);
hist[j] = hist[j-1];
}
sum64.w64 = MADD64(sum64.w64, hist[0], a[0]);
y = (sum64.r.hi32 << (32 - FBITS_LPC_COEFS)) | (sum64.r.lo32 >> FBITS_LPC_COEFS);
/* clip output (rare) */
hi32 = sum64.r.hi32;
if ((hi32 >> 31) != (hi32 >> (FBITS_LPC_COEFS-1)))
y = (hi32 >> 31) ^ 0x7fffffff;
hist[0] = y;
*audioCoef = y;
audioCoef += inc;
gbMask |= FASTABS(y);
} while (--size);
return gbMask;
}
/**************************************************************************************
* Function: TNSFilter
*
* Description: apply temporal noise shaping, if enabled
*
* Inputs: valid AACDecInfo struct
* index of current channel
*
* Outputs: updated transform coefficients
* updated minimum guard bit count for this channel
*
* Return: 0 if successful, -1 if error
**************************************************************************************/
int TNSFilter(AACDecInfo *aacDecInfo, int ch)
{
int win, winLen, nWindows, nSFB, filt, bottom, top, order, maxOrder, dir;
int start, end, size, tnsMaxBand, numFilt, gbMask;
int *audioCoef;
unsigned char *filtLength, *filtOrder, *filtRes, *filtDir;
signed char *filtCoef;
const unsigned /*char*/ int *tnsMaxBandTab;
const /*short*/ int *sfbTab;
ICSInfo *icsInfo;
TNSInfo *ti;
PSInfoBase *psi;
/* validate pointers */
if (!aacDecInfo || !aacDecInfo->psInfoBase)
return -1;
psi = (PSInfoBase *)(aacDecInfo->psInfoBase);
icsInfo = (ch == 1 && psi->commonWin == 1) ? &(psi->icsInfo[0]) : &(psi->icsInfo[ch]);
ti = &psi->tnsInfo[ch];
if (!ti->tnsDataPresent)
return 0;
if (icsInfo->winSequence == 2) {
nWindows = NWINDOWS_SHORT;
winLen = NSAMPS_SHORT;
nSFB = sfBandTotalShort[psi->sampRateIdx];
maxOrder = tnsMaxOrderShort[aacDecInfo->profile];
sfbTab = sfBandTabShort + sfBandTabShortOffset[psi->sampRateIdx];
tnsMaxBandTab = tnsMaxBandsShort + tnsMaxBandsShortOffset[aacDecInfo->profile];
tnsMaxBand = tnsMaxBandTab[psi->sampRateIdx];
} else {
nWindows = NWINDOWS_LONG;
winLen = NSAMPS_LONG;
nSFB = sfBandTotalLong[psi->sampRateIdx];
maxOrder = tnsMaxOrderLong[aacDecInfo->profile];
sfbTab = sfBandTabLong + sfBandTabLongOffset[psi->sampRateIdx];
tnsMaxBandTab = tnsMaxBandsLong + tnsMaxBandsLongOffset[aacDecInfo->profile];
tnsMaxBand = tnsMaxBandTab[psi->sampRateIdx];
}
if (tnsMaxBand > icsInfo->maxSFB)
tnsMaxBand = icsInfo->maxSFB;
filtRes = ti->coefRes;
filtLength = ti->length;
filtOrder = ti->order;
filtDir = ti->dir;
filtCoef = ti->coef;
gbMask = 0;
audioCoef = psi->coef[ch];
for (win = 0; win < nWindows; win++) {
bottom = nSFB;
numFilt = ti->numFilt[win];
for (filt = 0; filt < numFilt; filt++) {
top = bottom;
bottom = top - *filtLength++;
bottom = MAX(bottom, 0);
order = *filtOrder++;
order = MIN(order, maxOrder);
if (order) {
start = sfbTab[MIN(bottom, tnsMaxBand)];
end = sfbTab[MIN(top, tnsMaxBand)];
size = end - start;
if (size > 0) {
dir = *filtDir++;
if (dir)
start = end - 1;
DecodeLPCCoefs(order, filtRes[win], filtCoef, psi->tnsLPCBuf, psi->tnsWorkBuf);
gbMask |= FilterRegion(size, dir, order, audioCoef + start, psi->tnsLPCBuf, psi->tnsWorkBuf);
}
filtCoef += order;
}
}
audioCoef += winLen;
}
/* update guard bit count if necessary */
size = CLZ(gbMask) - 1;
if (psi->gbCurrent[ch] > size)
psi->gbCurrent[ch] = size;
return 0;
}
/* Code to generate invQuantXXX[] tables
* {
* int res, i, t;
* double powScale, iqfac, iqfac_m, d;
*
* powScale = pow(2.0, 31) * -1.0; / ** make coefficients negative for using MADD in kernel ** /
* for (res = 3; res <= 4; res++) {
* iqfac = ( ((1 << (res-1)) - 0.5) * (2.0 / M_PI) );
* iqfac_m = ( ((1 << (res-1)) + 0.5) * (2.0 / M_PI) );
* printf("static const int invQuant%d[16] = {\n", res);
* for (i = 0; i < 16; i++) {
* / ** extend bottom 4 bits into signed, 2's complement number ** /
* t = (i << 28) >> 28;
*
* if (t >= 0) d = sin(t / iqfac);
* else d = sin(t / iqfac_m);
*
* d *= powScale;
* printf("0x%08x, ", (int)(d > 0 ? d + 0.5 : d - 0.5));
* if ((i & 0x07) == 0x07)
* printf("\n");
* }
* printf("};\n\n");
* }
* }
*/