mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
411 lines
11 KiB
411 lines
11 KiB
/* |
|
* imdct.c |
|
* Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org> |
|
* Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca> |
|
* |
|
* The ifft algorithms in this file have been largely inspired by Dan |
|
* Bernstein's work, djbfft, available at http://cr.yp.to/djbfft.html |
|
* |
|
* This file is part of a52dec, a free ATSC A-52 stream decoder. |
|
* See http://liba52.sourceforge.net/ for updates. |
|
* |
|
* a52dec 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. |
|
* |
|
* a52dec 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
|
*/ |
|
|
|
#include "a52.h" |
|
#include "a52_internal.h" |
|
#include "mm_accel.h" |
|
|
|
typedef struct complex_s { |
|
sample_t real; |
|
sample_t imag; |
|
} complex_t; |
|
|
|
static uint8_t fftorder[] = { |
|
0,128, 64,192, 32,160,224, 96, 16,144, 80,208,240,112, 48,176, |
|
8,136, 72,200, 40,168,232,104,248,120, 56,184, 24,152,216, 88, |
|
4,132, 68,196, 36,164,228,100, 20,148, 84,212,244,116, 52,180, |
|
252,124, 60,188, 28,156,220, 92, 12,140, 76,204,236,108, 44,172, |
|
2,130, 66,194, 34,162,226, 98, 18,146, 82,210,242,114, 50,178, |
|
10,138, 74,202, 42,170,234,106,250,122, 58,186, 26,154,218, 90, |
|
254,126, 62,190, 30,158,222, 94, 14,142, 78,206,238,110, 46,174, |
|
6,134, 70,198, 38,166,230,102,246,118, 54,182, 22,150,214, 86 |
|
}; |
|
|
|
/* Root values for IFFT */ |
|
static sample_t roots16[3]; |
|
static sample_t roots32[7]; |
|
static sample_t roots64[15]; |
|
static sample_t roots128[31]; |
|
|
|
/* Twiddle factors for IMDCT */ |
|
static complex_t pre1[128]; |
|
static complex_t post1[64]; |
|
static complex_t pre2[64]; |
|
static complex_t post2[32]; |
|
|
|
static sample_t a52_imdct_window[256]; |
|
|
|
static void (* ifft128) (complex_t * buf); |
|
static void (* ifft64) (complex_t * buf); |
|
|
|
static inline void ifft2 (complex_t * buf) |
|
{ |
|
sample_t r, i; |
|
|
|
r = buf[0].real; |
|
i = buf[0].imag; |
|
buf[0].real += buf[1].real; |
|
buf[0].imag += buf[1].imag; |
|
buf[1].real = r - buf[1].real; |
|
buf[1].imag = i - buf[1].imag; |
|
} |
|
|
|
static inline void ifft4 (complex_t * buf) |
|
{ |
|
sample_t tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8; |
|
|
|
tmp1 = buf[0].real + buf[1].real; |
|
tmp2 = buf[3].real + buf[2].real; |
|
tmp3 = buf[0].imag + buf[1].imag; |
|
tmp4 = buf[2].imag + buf[3].imag; |
|
tmp5 = buf[0].real - buf[1].real; |
|
tmp6 = buf[0].imag - buf[1].imag; |
|
tmp7 = buf[2].imag - buf[3].imag; |
|
tmp8 = buf[3].real - buf[2].real; |
|
|
|
buf[0].real = tmp1 + tmp2; |
|
buf[0].imag = tmp3 + tmp4; |
|
buf[2].real = tmp1 - tmp2; |
|
buf[2].imag = tmp3 - tmp4; |
|
buf[1].real = tmp5 + tmp7; |
|
buf[1].imag = tmp6 + tmp8; |
|
buf[3].real = tmp5 - tmp7; |
|
buf[3].imag = tmp6 - tmp8; |
|
} |
|
|
|
/* basic radix-2 ifft butterfly */ |
|
|
|
#define BUTTERFLY_0(t0,t1,W0,W1,d0,d1) do { \ |
|
t0 = MUL (W1, d1) + MUL (W0, d0); \ |
|
t1 = MUL (W0, d1) - MUL (W1, d0); \ |
|
} while (0) |
|
|
|
/* radix-2 ifft butterfly with bias */ |
|
|
|
#define BUTTERFLY_B(t0,t1,W0,W1,d0,d1) do { \ |
|
t0 = BIAS (MUL (d1, W1) + MUL (d0, W0)); \ |
|
t1 = BIAS (MUL (d1, W0) - MUL (d0, W1)); \ |
|
} while (0) |
|
|
|
/* the basic split-radix ifft butterfly */ |
|
|
|
#define BUTTERFLY(a0,a1,a2,a3,wr,wi) do { \ |
|
BUTTERFLY_0 (tmp5, tmp6, wr, wi, a2.real, a2.imag); \ |
|
BUTTERFLY_0 (tmp8, tmp7, wr, wi, a3.imag, a3.real); \ |
|
tmp1 = tmp5 + tmp7; \ |
|
tmp2 = tmp6 + tmp8; \ |
|
tmp3 = tmp6 - tmp8; \ |
|
tmp4 = tmp7 - tmp5; \ |
|
a2.real = a0.real - tmp1; \ |
|
a2.imag = a0.imag - tmp2; \ |
|
a3.real = a1.real - tmp3; \ |
|
a3.imag = a1.imag - tmp4; \ |
|
a0.real += tmp1; \ |
|
a0.imag += tmp2; \ |
|
a1.real += tmp3; \ |
|
a1.imag += tmp4; \ |
|
} while (0) |
|
|
|
/* split-radix ifft butterfly, specialized for wr=1 wi=0 */ |
|
|
|
#define BUTTERFLY_ZERO(a0,a1,a2,a3) do { \ |
|
tmp1 = a2.real + a3.real; \ |
|
tmp2 = a2.imag + a3.imag; \ |
|
tmp3 = a2.imag - a3.imag; \ |
|
tmp4 = a3.real - a2.real; \ |
|
a2.real = a0.real - tmp1; \ |
|
a2.imag = a0.imag - tmp2; \ |
|
a3.real = a1.real - tmp3; \ |
|
a3.imag = a1.imag - tmp4; \ |
|
a0.real += tmp1; \ |
|
a0.imag += tmp2; \ |
|
a1.real += tmp3; \ |
|
a1.imag += tmp4; \ |
|
} while (0) |
|
|
|
/* split-radix ifft butterfly, specialized for wr=wi */ |
|
|
|
#define BUTTERFLY_HALF(a0,a1,a2,a3,w) do { \ |
|
tmp5 = MUL (a2.real + a2.imag, w); \ |
|
tmp6 = MUL (a2.imag - a2.real, w); \ |
|
tmp7 = MUL (a3.real - a3.imag, w); \ |
|
tmp8 = MUL (a3.imag + a3.real, w); \ |
|
tmp1 = tmp5 + tmp7; \ |
|
tmp2 = tmp6 + tmp8; \ |
|
tmp3 = tmp6 - tmp8; \ |
|
tmp4 = tmp7 - tmp5; \ |
|
a2.real = a0.real - tmp1; \ |
|
a2.imag = a0.imag - tmp2; \ |
|
a3.real = a1.real - tmp3; \ |
|
a3.imag = a1.imag - tmp4; \ |
|
a0.real += tmp1; \ |
|
a0.imag += tmp2; \ |
|
a1.real += tmp3; \ |
|
a1.imag += tmp4; \ |
|
} while (0) |
|
|
|
static inline void ifft8 (complex_t * buf) |
|
{ |
|
sample_t tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8; |
|
|
|
ifft4 (buf); |
|
ifft2 (buf + 4); |
|
ifft2 (buf + 6); |
|
BUTTERFLY_ZERO (buf[0], buf[2], buf[4], buf[6]); |
|
BUTTERFLY_HALF (buf[1], buf[3], buf[5], buf[7], roots16[1]); |
|
} |
|
|
|
static void ifft_pass (complex_t * buf, sample_t * weight, int n) |
|
{ |
|
complex_t * buf1; |
|
complex_t * buf2; |
|
complex_t * buf3; |
|
sample_t tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8; |
|
int i; |
|
|
|
buf++; |
|
buf1 = buf + n; |
|
buf2 = buf + 2 * n; |
|
buf3 = buf + 3 * n; |
|
|
|
BUTTERFLY_ZERO (buf[-1], buf1[-1], buf2[-1], buf3[-1]); |
|
|
|
i = n - 1; |
|
|
|
do { |
|
BUTTERFLY (buf[0], buf1[0], buf2[0], buf3[0], |
|
weight[0], weight[2*i-n]); |
|
buf++; |
|
buf1++; |
|
buf2++; |
|
buf3++; |
|
weight++; |
|
} while (--i); |
|
} |
|
|
|
static void ifft16 (complex_t * buf) |
|
{ |
|
ifft8 (buf); |
|
ifft4 (buf + 8); |
|
ifft4 (buf + 12); |
|
ifft_pass (buf, roots16, 4); |
|
} |
|
|
|
static void ifft32 (complex_t * buf) |
|
{ |
|
ifft16 (buf); |
|
ifft8 (buf + 16); |
|
ifft8 (buf + 24); |
|
ifft_pass (buf, roots32, 8); |
|
} |
|
|
|
static void ifft64_c (complex_t * buf) |
|
{ |
|
ifft32 (buf); |
|
ifft16 (buf + 32); |
|
ifft16 (buf + 48); |
|
ifft_pass (buf, roots64, 16); |
|
} |
|
|
|
static void ifft128_c (complex_t * buf) |
|
{ |
|
ifft32 (buf); |
|
ifft16 (buf + 32); |
|
ifft16 (buf + 48); |
|
ifft_pass (buf, roots64, 16); |
|
|
|
ifft32 (buf + 64); |
|
ifft32 (buf + 96); |
|
ifft_pass (buf, roots128, 32); |
|
} |
|
|
|
void a52_imdct_512 (sample_t * data, sample_t * delay, sample_t bias) |
|
{ |
|
int i, k; |
|
sample_t t_r, t_i, a_r, a_i, b_r, b_i, w_1, w_2; |
|
const sample_t * window = a52_imdct_window; |
|
complex_t buf[128]; |
|
|
|
for (i = 0; i < 128; i++) { |
|
k = fftorder[i]; |
|
t_r = pre1[i].real; |
|
t_i = pre1[i].imag; |
|
BUTTERFLY_0 (buf[i].real, buf[i].imag, t_r, t_i, data[k], data[255-k]); |
|
} |
|
|
|
ifft128 (buf); |
|
|
|
/* Post IFFT complex multiply plus IFFT complex conjugate*/ |
|
/* Window and convert to real valued signal */ |
|
for (i = 0; i < 64; i++) { |
|
/* y[n] = z[n] * (xcos1[n] + j * xsin1[n]) ; */ |
|
t_r = post1[i].real; |
|
t_i = post1[i].imag; |
|
BUTTERFLY_0 (a_r, a_i, t_i, t_r, buf[i].imag, buf[i].real); |
|
BUTTERFLY_0 (b_r, b_i, t_r, t_i, buf[127-i].imag, buf[127-i].real); |
|
|
|
w_1 = window[2*i]; |
|
w_2 = window[255-2*i]; |
|
BUTTERFLY_B (data[255-2*i], data[2*i], w_2, w_1, a_r, delay[2*i]); |
|
delay[2*i] = a_i; |
|
|
|
w_1 = window[2*i+1]; |
|
w_2 = window[254-2*i]; |
|
BUTTERFLY_B (data[2*i+1], data[254-2*i], w_1, w_2, b_r, delay[2*i+1]); |
|
delay[2*i+1] = b_i; |
|
} |
|
} |
|
|
|
void a52_imdct_256 (sample_t * data, sample_t * delay, sample_t bias) |
|
{ |
|
int i, k; |
|
sample_t t_r, t_i, a_r, a_i, b_r, b_i, c_r, c_i, d_r, d_i, w_1, w_2; |
|
const sample_t * window = a52_imdct_window; |
|
complex_t buf1[64], buf2[64]; |
|
|
|
/* Pre IFFT complex multiply plus IFFT cmplx conjugate */ |
|
for (i = 0; i < 64; i++) { |
|
k = fftorder[i]; |
|
t_r = pre2[i].real; |
|
t_i = pre2[i].imag; |
|
BUTTERFLY_0 (buf1[i].real, buf1[i].imag, t_r, t_i, data[k], data[254-k]); |
|
BUTTERFLY_0 (buf2[i].real, buf2[i].imag, t_r, t_i, data[k+1], data[255-k]); |
|
} |
|
|
|
ifft64 (buf1); |
|
ifft64 (buf2); |
|
|
|
/* Post IFFT complex multiply */ |
|
/* Window and convert to real valued signal */ |
|
for (i = 0; i < 32; i++) { |
|
/* y1[n] = z1[n] * (xcos2[n] + j * xs in2[n]) ; */ |
|
t_r = post2[i].real; |
|
t_i = post2[i].imag; |
|
BUTTERFLY_0 (a_r, a_i, t_i, t_r, buf1[i].imag, buf1[i].real); |
|
BUTTERFLY_0 (b_r, b_i, t_r, t_i, buf1[63-i].imag, buf1[63-i].real); |
|
BUTTERFLY_0 (c_r, c_i, t_i, t_r, buf2[i].imag, buf2[i].real); |
|
BUTTERFLY_0 (d_r, d_i, t_r, t_i, buf2[63-i].imag, buf2[63-i].real); |
|
|
|
w_1 = window[2*i]; |
|
w_2 = window[255-2*i]; |
|
BUTTERFLY_B (data[255-2*i], data[2*i], w_2, w_1, a_r, delay[2*i]); |
|
delay[2*i] = c_i; |
|
|
|
w_1 = window[128+2*i]; |
|
w_2 = window[127-2*i]; |
|
BUTTERFLY_B (data[128+2*i], data[127-2*i], w_1, w_2, a_i, delay[127-2*i]); |
|
delay[127-2*i] = c_r; |
|
|
|
w_1 = window[2*i+1]; |
|
w_2 = window[254-2*i]; |
|
BUTTERFLY_B (data[254-2*i], data[2*i+1], w_2, w_1, b_i, delay[2*i+1]); |
|
delay[2*i+1] = d_r; |
|
|
|
w_1 = window[129+2*i]; |
|
w_2 = window[126-2*i]; |
|
BUTTERFLY_B (data[129+2*i], data[126-2*i], w_1, w_2, b_r, delay[126-2*i]); |
|
delay[126-2*i] = d_i; |
|
} |
|
} |
|
|
|
static double besselI0 (double x) |
|
{ |
|
double bessel = 1; |
|
int i = 100; |
|
|
|
do |
|
bessel = bessel * x / (i * i) + 1; |
|
while (--i); |
|
return bessel; |
|
} |
|
|
|
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; |
|
} |
|
}
|
|
|