ref: a2a56b3ea59188e2e2b60b69a0a8f77aa3093144
dir: /libfaad/sbr_util.c/
/*
** FAAD - Freeware Advanced Audio Decoder
** Copyright (C) 2002 M. Bakker
**
** 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.
**
** $Id: sbr_util.c,v 1.1 2002/09/29 22:19:48 menno Exp $
**/
#include "common.h"
#ifdef SBR
#include <stdlib.h>
#include "sbr_util.h"
/* calculate the start QMF channel for the master frequency band table */
/* parameter is also called k0 */
uint16_t qmf_start_channel(uint8_t bs_start_freq, uint32_t sample_rate)
{
static uint8_t offset[] = {
0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 16, 20, 24, 28, 33
};
uint8_t startMin;
if (sample_rate >= 64000)
{
startMin = (uint8_t)((5000.*128.)/(float)sample_rate + 0.5);
} else if (sample_rate < 32000) {
startMin = (uint8_t)((3000.*128.)/(float)sample_rate + 0.5);
} else {
startMin = (uint8_t)((4000.*128.)/(float)sample_rate + 0.5);
}
return startMin + offset[bs_start_freq];
}
static int32_t longcmp(const void *a, const void *b)
{
return ((int32_t)(*(int32_t*)a - *(int32_t*)b));
}
/* calculate the stop QMF channel for the master frequency band table */
/* parameter is also called k2 */
uint16_t qmf_stop_channel(uint8_t bs_stop_freq, uint32_t sample_rate,
uint16_t k0)
{
if (bs_stop_freq == 15)
return k0 * 3;
else if (bs_stop_freq == 14)
return k0 * 2;
else {
uint8_t i;
uint8_t stopMin;
uint32_t stopDk[13], k2;
if (sample_rate >= 64000)
{
stopMin = (uint8_t)((10000.*128.)/(float)sample_rate + 0.5);
} else if (sample_rate < 32000) {
stopMin = (uint8_t)((6000.*128.)/(float)sample_rate + 0.5);
} else {
stopMin = (uint8_t)((8000.*128.)/(float)sample_rate + 0.5);
}
/* TODO: PUT THIS IN MAPLE, CAN BE SIMPLIFIED A LOT */
for (i = 0; i < 13; i++)
{
stopDk[i] = (uint32_t)(stopMin*pow(64./(float)stopMin, (i+1)/13.) + 0.5) -
(uint32_t)(stopMin*pow(64./(float)stopMin, i/13.) + 0.5);
}
/* needed? or does this always reverse the array? */
qsort(stopDk, 13, sizeof(stopDk[0]), longcmp);
k2 = stopMin;
for (i = 0; i < bs_stop_freq-1; i++)
{
k2 += stopDk[i];
}
return k2;
}
return 0;
}
/* calculate the master frequency table from k0, k2, bs_freq_scale
and bs_alter_scale
returns N_master
version for bs_freq_scale = 0
*/
uint32_t master_frequency_table_fs0(int32_t *f_master,
uint16_t k0, uint16_t k2,
uint8_t bs_alter_scale)
{
int8_t incr;
uint8_t k;
uint8_t dk;
uint32_t nrBands, k2Achieved;
int32_t k2Diff, vDk[100 /*TODO*/];
/* mft only defined for k2 > k0 */
if (k2 <= k0)
return 0;
dk = bs_alter_scale ? 2 : 1;
nrBands = 2 * (int32_t)((k2-k0)/(float)dk*2. + 0.5);
k2Achieved = k0 + nrBands * dk;
k2Diff = k2 - k2Achieved;
for (k = 0; k <= nrBands; k++)
vDk[k] = dk;
if (k2Diff)
{
incr = (k2Diff > 0) ? -1 : 1;
k = (k2Diff > 0) ? (nrBands-1) : 0;
while (k2Diff != 0)
{
vDk[k] = vDk[k] - 1;
k += incr;
k2Diff += incr;
}
}
f_master[0] = k0;
for (k = 1; k <= nrBands; k++)
f_master[k] = f_master[k-1] + vDk[k-1];
return nrBands;
}
/*
version for bs_freq_scale > 0
*/
uint32_t master_frequency_table(int32_t *f_master,
uint16_t k0, uint16_t k2,
uint8_t bs_freq_scale,
uint8_t bs_alter_scale)
{
uint8_t k, bands, twoRegions;
uint16_t k1;
uint32_t nrBand0, nrBand1, N_master;
int32_t max_vDk0, min_vDk1;
int32_t vDk0[100 /*TODO*/], vDk1[100 /*TODO*/];
int32_t vk0[100 /*TODO*/], vk1[100 /*TODO*/];
float warp;
uint8_t temp1[] = { 12, 10, 8 };
float temp2[] = { 1.0, 1.3 };
/* mft only defined for k2 > k0 */
if (k2 <= k0)
return 0;
bands = temp1[bs_freq_scale-1];
warp = temp2[bs_alter_scale];
if ((float)k2/(float)k0 > 2.2449)
{
twoRegions = 1;
k1 = 2 * k0;
} else {
twoRegions = 0;
k1 = k2;
}
nrBand0 = 2 * (int32_t)(bands * log(k1/k0)/(2.0*log(2.0)) + 0.5);
max_vDk0 = 0;
for (k = 0; k <= nrBand0; k++)
{
vDk0[k] = (int32_t)(k0 * pow((float)k1/(float)k0, (k+1)/(float)nrBand0)+0.5) -
(int32_t)(k0 * pow((float)k1/(float)k0, k/(float)nrBand0)+0.5);
max_vDk0 = (max_vDk0 < vDk0[k]) ? vDk0[k] : max_vDk0;
}
/* needed? */
qsort(vDk0, nrBand0 + 1, sizeof(vDk0[0]), longcmp);
vk0[0] = k0;
for (k = 1; k <= nrBand0; k++)
{
vk0[k] = vk0[k-1] + vDk0[k-1];
}
if (!twoRegions)
{
for (k = 0; k <= nrBand0; k++)
f_master[k] = vk0[k];
return nrBand0;
}
nrBand1 = 2 * (int32_t)(bands * log((float)k2/(float)k1)/(2.0 * log(2.0) * warp) + 0.5);
min_vDk1 = 9999999;
for (k = 0; k <= nrBand1 - 1; k++)
{
vDk1[k] = (int32_t)(k0 * pow((float)k1/(float)k0, (k+1)/(float)nrBand1)+0.5) -
(int32_t)(k0 * pow((float)k1/(float)k0, k/(float)nrBand1)+0.5);
min_vDk1 = (min_vDk1 > vDk1[k]) ? vDk1[k] : min_vDk1;
}
if (min_vDk1 < max_vDk0)
{
int32_t change;
qsort(vDk1, nrBand1 + 1, sizeof(vDk1[0]), longcmp);
change = max_vDk0 - vDk1[0];
vDk1[0] = max_vDk0;
vDk1[nrBand1 - 1] = vDk1[nrBand1 - 1] - change;
}
qsort(vDk1, nrBand1 + 1, sizeof(vDk1[0]), longcmp);
vk1[0] = k1;
for (k = 1; k <= nrBand1; k++)
{
vk1[k] = vk1[k-1] + vDk1[k-1];
}
N_master = nrBand0 + nrBand1;
for (k = 0; k <= nrBand0; k++)
{
f_master[k] = vk0[k];
}
for (k = nrBand0 + 1; k <= N_master; k++)
{
f_master[k] = vk1[k - nrBand0];
}
return N_master;
}
#endif