// Kaiser window function
void kaiser(int n, double beta, double* d)
{
if (n == 1) {
d[0] = 1.0;
return;
}
int m = n - 1;
for (int i = 0; i < n; i++) {
double k = 2.0 * beta / m * sqrt(double(i * (m - i)));
d[i] = besselI0(k) / besselI0(beta);
}
}
Real besselK0(Real x)
{
if (x < 0)
return std::numeric_limits<Real>::quiet_NaN();
if (0 == x)
return std::numeric_limits<Real>::infinity();
if (x <= 2)
{
// use 10.31.1 [DLMF]
// the constants are digamma[i + 1] / (i!)^2
const Real c[7] = {R(-0.5772156649 ), R(0.4227843351 ),
R( 0.2306960838 ), R(0.03489215746 ),
R( 0.002614787619), R(0.0001184803936),
R( 3.612624103e-6)};
const Real t = R(0.25) * x * x;
Real sum = c[6];
for(int i = 5; i >= 0; --i)
sum = sum * t + c[i];
return -std::log(R(0.5) * x) * besselI0(x) + sum;
}
else
{
// use 10.40.2 [DLMF]
const Real c[7] = {R( 1.25331414), R(-0.07832358), R( 0.02189568),
R(-0.01062446), R( 0.00587872), R(-0.00251540),
R( 0.00053208)};
const Real t = 2 / x;
Real sum = c[6];
for (int i = 5; i >= 0; --i)
sum = sum * t + c[i];
return std::exp(-x) * sum / std::sqrt(x);
}
}
void a52_imdct_init (uint32_t mm_accel)
{
#ifdef BUILDFIXED
int i, k;
double sum;
double local_imdct_window[256];
/* compute imdct window - kaiser-bessel derived window, alpha = 5.0 */
sum = 0;
for (i = 0; i < 256; i++) {
sum += besselI0 (i * (256 - i) * (5 * M_PI / 256) * (5 * M_PI / 256));
local_imdct_window[i] = sum;
}
sum++;
for (i = 0; i < 256; i++)
a52_imdct_window[i] = SAMPLE (sqrt (local_imdct_window[i] / sum));
for (i = 0; i < 3; i++)
roots16[i] = SAMPLE (cos ((M_PI / 8) * (i + 1)));
for (i = 0; i < 7; i++)
roots32[i] = SAMPLE (cos ((M_PI / 16) * (i + 1)));
for (i = 0; i < 15; i++)
roots64[i] = SAMPLE (cos ((M_PI / 32) * (i + 1)));
for (i = 0; i < 31; i++)
roots128[i] = SAMPLE (cos ((M_PI / 64) * (i + 1)));
for (i = 0; i < 64; i++) {
k = fftorder[i] / 2 + 64;
pre1[i].real = SAMPLE (cos ((M_PI / 256) * (k - 0.25)));
pre1[i].imag = SAMPLE (sin ((M_PI / 256) * (k - 0.25)));
}
for (i = 64; i < 128; i++) {
k = fftorder[i] / 2 + 64;
pre1[i].real = SAMPLE (-cos ((M_PI / 256) * (k - 0.25)));
pre1[i].imag = SAMPLE (-sin ((M_PI / 256) * (k - 0.25)));
}
for (i = 0; i < 64; i++) {
post1[i].real = SAMPLE (cos ((M_PI / 256) * (i + 0.5)));
post1[i].imag = SAMPLE (sin ((M_PI / 256) * (i + 0.5)));
}
for (i = 0; i < 64; i++) {
k = fftorder[i] / 4;
pre2[i].real = SAMPLE (cos ((M_PI / 128) * (k - 0.25)));
pre2[i].imag = SAMPLE (sin ((M_PI / 128) * (k - 0.25)));
}
for (i = 0; i < 32; i++) {
post2[i].real = SAMPLE (cos ((M_PI / 128) * (i + 0.5)));
post2[i].imag = SAMPLE (sin ((M_PI / 128) * (i + 0.5)));
}
/*
#ifdef LIBA52_DJBFFT
if (mm_accel & MM_ACCEL_DJBFFT) {
ifft128 = (void (*) (complex_t *)) fftc4_un128;
ifft64 = (void (*) (complex_t *)) fftc4_un64;
} else
#endif
{
ifft128 = ifft128_c;
ifft64 = ifft64_c;
}
*/
#ifdef CREATE_CONST
{
FILE* f = fopen("imdct_const.h","w+");
dumpsample(f,roots16,"roots16",sizeof(roots16)/sizeof(sample_t));
dumpsample(f,roots32,"roots32",sizeof(roots32)/sizeof(sample_t));
dumpsample(f,roots64,"roots64",sizeof(roots64)/sizeof(sample_t));
dumpsample(f,roots128,"roots128",sizeof(roots128)/sizeof(sample_t));
dumpsample(f,a52_imdct_window,"a52_imdct_window",sizeof(a52_imdct_window)/sizeof(sample_t));
dumpcomplex(f,pre1,"pre1",sizeof(pre1)/sizeof(complex_t));
dumpcomplex(f,pre2,"pre2",sizeof(pre2)/sizeof(complex_t));
dumpcomplex(f,post1,"post1",sizeof(post1)/sizeof(complex_t));
dumpcomplex(f,post2,"post2",sizeof(post2)/sizeof(complex_t));
fclose(f);
}
#endif
#endif
}
void a52_imdct_init (uint32_t mm_accel)
{
int i, k;
double sum;
/* compute imdct window - kaiser-bessel derived window, alpha = 5.0 */
sum = 0;
for (i = 0; i < 256; i++) {
sum += besselI0 (i * (256 - i) * (5 * M_PI / 256) * (5 * M_PI / 256));
a52_imdct_window[i] = sum;
}
sum++;
for (i = 0; i < 256; i++)
a52_imdct_window[i] = sqrt (a52_imdct_window[i] / sum);
for (i = 0; i < 3; i++)
roots16[i] = cos ((M_PI / 8) * (i + 1));
for (i = 0; i < 7; i++)
roots32[i] = cos ((M_PI / 16) * (i + 1));
for (i = 0; i < 15; i++)
roots64[i] = cos ((M_PI / 32) * (i + 1));
for (i = 0; i < 31; i++)
roots128[i] = cos ((M_PI / 64) * (i + 1));
for (i = 0; i < 64; i++) {
k = fftorder[i] / 2 + 64;
pre1[i].real = cos ((M_PI / 256) * (k - 0.25));
pre1[i].imag = sin ((M_PI / 256) * (k - 0.25));
}
for (i = 64; i < 128; i++) {
k = fftorder[i] / 2 + 64;
pre1[i].real = -cos ((M_PI / 256) * (k - 0.25));
pre1[i].imag = -sin ((M_PI / 256) * (k - 0.25));
}
for (i = 0; i < 64; i++) {
post1[i].real = cos ((M_PI / 256) * (i + 0.5));
post1[i].imag = sin ((M_PI / 256) * (i + 0.5));
}
for (i = 0; i < 64; i++) {
k = fftorder[i] / 4;
pre2[i].real = cos ((M_PI / 128) * (k - 0.25));
pre2[i].imag = sin ((M_PI / 128) * (k - 0.25));
}
for (i = 0; i < 32; i++) {
post2[i].real = cos ((M_PI / 128) * (i + 0.5));
post2[i].imag = sin ((M_PI / 128) * (i + 0.5));
}
#ifdef LIBA52_DJBFFT
if (mm_accel & MM_ACCEL_DJBFFT) {
fprintf (stderr, "Using djbfft for IMDCT transform\n");
ifft128 = (void (*) (complex_t *)) fftc4_un128;
ifft64 = (void (*) (complex_t *)) fftc4_un64;
} else
#endif
{
fprintf (stderr, "No accelerated IMDCT transform found\n");
ifft128 = ifft128_c;
ifft64 = ifft64_c;
}
}
void a52_imdct_init (uint32_t mm_accel)
{
int i, k;
double sum;
sample_t local_imdct_window[256];
/* compute imdct window - kaiser-bessel derived window, alpha = 5.0 */
sum = 0;
for (i = 0; i < 256; i++) {
sum += besselI0 (i * (256 - i) * (5 * M_PI / 256) * (5 * M_PI / 256));
local_imdct_window[i] = sum;
}
sum++;
for (i = 0; i < 256; i++)
a52_imdct_window[i] = (sample_t) (sqrt (local_imdct_window[i] / sum));
for (i = 0; i < 3; i++)
roots16[i] = cos ((M_PI / 8) * (i + 1));
for (i = 0; i < 7; i++)
roots32[i] = cos ((M_PI / 16) * (i + 1));
for (i = 0; i < 15; i++)
roots64[i] = cos ((M_PI / 32) * (i + 1));
for (i = 0; i < 31; i++)
roots128[i] = cos ((M_PI / 64) * (i + 1));
for (i = 0; i < 64; i++) {
k = fftorder[i] / 2 + 64;
pre1[i].real = cos ((M_PI / 256) * (k - 0.25));
pre1[i].imag = sin ((M_PI / 256) * (k - 0.25));
}
for (i = 64; i < 128; i++) {
k = fftorder[i] / 2 + 64;
pre1[i].real = -cos ((M_PI / 256) * (k - 0.25));
pre1[i].imag = -sin ((M_PI / 256) * (k - 0.25));
}
for (i = 0; i < 64; i++) {
post1[i].real = cos ((M_PI / 256) * (i + 0.5));
post1[i].imag = sin ((M_PI / 256) * (i + 0.5));
}
for (i = 0; i < 64; i++) {
k = fftorder[i] / 4;
pre2[i].real = cos ((M_PI / 128) * (k - 0.25));
pre2[i].imag = sin ((M_PI / 128) * (k - 0.25));
}
for (i = 0; i < 32; i++) {
post2[i].real = cos ((M_PI / 128) * (i + 0.5));
post2[i].imag = sin ((M_PI / 128) * (i + 0.5));
}
{
ifft128 = ifft128_c;
ifft64 = ifft64_c;
}
}
void a52_imdct_init (uint32_t mm_accel)
{
int i, k;
double sum;
double local_imdct_window[256];
/* compute imdct window - kaiser-bessel derived window, alpha = 5.0 */
sum = 0;
for (i = 0; i < 256; i++) {
sum += besselI0 (i * (256 - i) * (5 * M_PI / 256) * (5 * M_PI / 256));
local_imdct_window[i] = sum;
}
sum++;
for (i = 0; i < 256; i++)
a52_imdct_window[i] = SAMPLE (sqrt (local_imdct_window[i] / sum));
for (i = 0; i < 3; i++)
roots16[i] = SAMPLE (cos ((M_PI / 8) * (i + 1)));
for (i = 0; i < 7; i++)
roots32[i] = SAMPLE (cos ((M_PI / 16) * (i + 1)));
for (i = 0; i < 15; i++)
roots64[i] = SAMPLE (cos ((M_PI / 32) * (i + 1)));
for (i = 0; i < 31; i++)
roots128[i] = SAMPLE (cos ((M_PI / 64) * (i + 1)));
for (i = 0; i < 64; i++) {
k = fftorder[i] / 2 + 64;
pre1[i].real = SAMPLE (cos ((M_PI / 256) * (k - 0.25)));
pre1[i].imag = SAMPLE (sin ((M_PI / 256) * (k - 0.25)));
}
for (i = 64; i < 128; i++) {
k = fftorder[i] / 2 + 64;
pre1[i].real = SAMPLE (-cos ((M_PI / 256) * (k - 0.25)));
pre1[i].imag = SAMPLE (-sin ((M_PI / 256) * (k - 0.25)));
}
for (i = 0; i < 64; i++) {
post1[i].real = SAMPLE (cos ((M_PI / 256) * (i + 0.5)));
post1[i].imag = SAMPLE (sin ((M_PI / 256) * (i + 0.5)));
}
for (i = 0; i < 64; i++) {
k = fftorder[i] / 4;
pre2[i].real = SAMPLE (cos ((M_PI / 128) * (k - 0.25)));
pre2[i].imag = SAMPLE (sin ((M_PI / 128) * (k - 0.25)));
}
for (i = 0; i < 32; i++) {
post2[i].real = SAMPLE (cos ((M_PI / 128) * (i + 0.5)));
post2[i].imag = SAMPLE (sin ((M_PI / 128) * (i + 0.5)));
}
#ifdef LIBA52_DJBFFT
if (mm_accel & MM_ACCEL_DJBFFT) {
ifft128 = (void (*) (complex_t *)) fftc4_un128;
ifft64 = (void (*) (complex_t *)) fftc4_un64;
} else
#endif
{
ifft128 = ifft128_c;
ifft64 = ifft64_c;
}
}
