/*
* FFT/IFFT transforms
- * Copyright (c) 2002 Fabrice Bellard.
+ * Copyright (c) 2008 Loren Merritt
+ * Copyright (c) 2002 Fabrice Bellard
+ * Partly based on libdjbfft by D. J. Bernstein
*
- * This library is free software; you can redistribute it and/or
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
+ * version 2.1 of the License, or (at your option) any later version.
*
- * This library is distributed in the hope that it will be useful,
+ * Libav 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
-#include "dsputil.h"
/**
- * The size of the FFT is 2^nbits. If inverse is TRUE, inverse FFT is
- * done
+ * @file
+ * FFT/IFFT transforms.
*/
-int fft_init(FFTContext *s, int nbits, int inverse)
+
+#include <stdlib.h>
+#include <string.h>
+#include "libavutil/mathematics.h"
+#include "fft.h"
+#include "fft-internal.h"
+
+/* cos(2*pi*x/n) for 0<=x<=n/4, followed by its reverse */
+#if !CONFIG_HARDCODED_TABLES
+COSTABLE(16);
+COSTABLE(32);
+COSTABLE(64);
+COSTABLE(128);
+COSTABLE(256);
+COSTABLE(512);
+COSTABLE(1024);
+COSTABLE(2048);
+COSTABLE(4096);
+COSTABLE(8192);
+COSTABLE(16384);
+COSTABLE(32768);
+COSTABLE(65536);
+#endif
+COSTABLE_CONST FFTSample * const FFT_NAME(ff_cos_tabs)[] = {
+ NULL, NULL, NULL, NULL,
+ FFT_NAME(ff_cos_16),
+ FFT_NAME(ff_cos_32),
+ FFT_NAME(ff_cos_64),
+ FFT_NAME(ff_cos_128),
+ FFT_NAME(ff_cos_256),
+ FFT_NAME(ff_cos_512),
+ FFT_NAME(ff_cos_1024),
+ FFT_NAME(ff_cos_2048),
+ FFT_NAME(ff_cos_4096),
+ FFT_NAME(ff_cos_8192),
+ FFT_NAME(ff_cos_16384),
+ FFT_NAME(ff_cos_32768),
+ FFT_NAME(ff_cos_65536),
+};
+
+static void ff_fft_permute_c(FFTContext *s, FFTComplex *z);
+static void ff_fft_calc_c(FFTContext *s, FFTComplex *z);
+
+static int split_radix_permutation(int i, int n, int inverse)
{
- int i, j, m, n;
- float alpha, c1, s1, s2;
-
+ int m;
+ if(n <= 2) return i&1;
+ m = n >> 1;
+ if(!(i&m)) return split_radix_permutation(i, m, inverse)*2;
+ m >>= 1;
+ if(inverse == !(i&m)) return split_radix_permutation(i, m, inverse)*4 + 1;
+ else return split_radix_permutation(i, m, inverse)*4 - 1;
+}
+
+av_cold void ff_init_ff_cos_tabs(int index)
+{
+#if !CONFIG_HARDCODED_TABLES
+ int i;
+ int m = 1<<index;
+ double freq = 2*M_PI/m;
+ FFTSample *tab = FFT_NAME(ff_cos_tabs)[index];
+ for(i=0; i<=m/4; i++)
+ tab[i] = FIX15(cos(i*freq));
+ for(i=1; i<m/4; i++)
+ tab[m/2-i] = tab[i];
+#endif
+}
+
+static const int avx_tab[] = {
+ 0, 4, 1, 5, 8, 12, 9, 13, 2, 6, 3, 7, 10, 14, 11, 15
+};
+
+static int is_second_half_of_fft32(int i, int n)
+{
+ if (n <= 32)
+ return i >= 16;
+ else if (i < n/2)
+ return is_second_half_of_fft32(i, n/2);
+ else if (i < 3*n/4)
+ return is_second_half_of_fft32(i - n/2, n/4);
+ else
+ return is_second_half_of_fft32(i - 3*n/4, n/4);
+}
+
+static av_cold void fft_perm_avx(FFTContext *s)
+{
+ int i;
+ int n = 1 << s->nbits;
+
+ for (i = 0; i < n; i += 16) {
+ int k;
+ if (is_second_half_of_fft32(i, n)) {
+ for (k = 0; k < 16; k++)
+ s->revtab[-split_radix_permutation(i + k, n, s->inverse) & (n - 1)] =
+ i + avx_tab[k];
+
+ } else {
+ for (k = 0; k < 16; k++) {
+ int j = i + k;
+ j = (j & ~7) | ((j >> 1) & 3) | ((j << 2) & 4);
+ s->revtab[-split_radix_permutation(i + k, n, s->inverse) & (n - 1)] = j;
+ }
+ }
+ }
+}
+
+av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse)
+{
+ int i, j, n;
+
+ if (nbits < 2 || nbits > 16)
+ goto fail;
s->nbits = nbits;
n = 1 << nbits;
- s->exptab = av_malloc((n / 2) * sizeof(FFTComplex));
- if (!s->exptab)
- goto fail;
s->revtab = av_malloc(n * sizeof(uint16_t));
if (!s->revtab)
goto fail;
+ s->tmp_buf = av_malloc(n * sizeof(FFTComplex));
+ if (!s->tmp_buf)
+ goto fail;
s->inverse = inverse;
+ s->fft_permutation = FF_FFT_PERM_DEFAULT;
- s2 = inverse ? 1.0 : -1.0;
-
- for(i=0;i<(n/2);i++) {
- alpha = 2 * M_PI * (float)i / (float)n;
- c1 = cos(alpha);
- s1 = sin(alpha) * s2;
- s->exptab[i].re = c1;
- s->exptab[i].im = s1;
- }
- s->fft_calc = fft_calc_c;
- s->exptab1 = NULL;
-
- /* compute constant table for HAVE_SSE version */
-#if (defined(HAVE_MMX) && defined(HAVE_BUILTIN_VECTOR)) || defined(HAVE_ALTIVEC)
- {
- int has_vectors;
-
-#if defined(HAVE_MMX)
- has_vectors = mm_support() & MM_SSE;
-#else
- /* XXX: should also use mm_support() ? */
- has_vectors = has_altivec() & MM_ALTIVEC;
+ s->fft_permute = ff_fft_permute_c;
+ s->fft_calc = ff_fft_calc_c;
+#if CONFIG_MDCT
+ s->imdct_calc = ff_imdct_calc_c;
+ s->imdct_half = ff_imdct_half_c;
+ s->mdct_calc = ff_mdct_calc_c;
#endif
- if (has_vectors) {
- int np, nblocks, np2, l;
- FFTComplex *q;
-
- np = 1 << nbits;
- nblocks = np >> 3;
- np2 = np >> 1;
- s->exptab1 = av_malloc(np * 2 * sizeof(FFTComplex));
- if (!s->exptab1)
- goto fail;
- q = s->exptab1;
- do {
- for(l = 0; l < np2; l += 2 * nblocks) {
- *q++ = s->exptab[l];
- *q++ = s->exptab[l + nblocks];
-
- q->re = -s->exptab[l].im;
- q->im = s->exptab[l].re;
- q++;
- q->re = -s->exptab[l + nblocks].im;
- q->im = s->exptab[l + nblocks].re;
- q++;
- }
- nblocks = nblocks >> 1;
- } while (nblocks != 0);
- av_freep(&s->exptab);
-#if defined(HAVE_MMX)
- s->fft_calc = fft_calc_sse;
+
+#if CONFIG_FFT_FLOAT
+ if (ARCH_ARM) ff_fft_init_arm(s);
+ if (HAVE_ALTIVEC) ff_fft_init_altivec(s);
+ if (ARCH_X86) ff_fft_init_x86(s);
+ if (CONFIG_MDCT) s->mdct_calcw = s->mdct_calc;
#else
- s->fft_calc = fft_calc_altivec;
-#endif
- }
- }
+ if (CONFIG_MDCT) s->mdct_calcw = ff_mdct_calcw_c;
+ if (ARCH_ARM) ff_fft_fixed_init_arm(s);
#endif
- /* compute bit reverse table */
+ for(j=4; j<=nbits; j++) {
+ ff_init_ff_cos_tabs(j);
+ }
- for(i=0;i<n;i++) {
- m=0;
- for(j=0;j<nbits;j++) {
- m |= ((i >> j) & 1) << (nbits-j-1);
+ if (s->fft_permutation == FF_FFT_PERM_AVX) {
+ fft_perm_avx(s);
+ } else {
+ for(i=0; i<n; i++) {
+ int j = i;
+ if (s->fft_permutation == FF_FFT_PERM_SWAP_LSBS)
+ j = (j&~3) | ((j>>1)&1) | ((j<<1)&2);
+ s->revtab[-split_radix_permutation(i, n, s->inverse) & (n-1)] = j;
}
- s->revtab[i]=m;
}
+
return 0;
fail:
av_freep(&s->revtab);
- av_freep(&s->exptab);
- av_freep(&s->exptab1);
+ av_freep(&s->tmp_buf);
return -1;
}
-/* butter fly op */
-#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
+static void ff_fft_permute_c(FFTContext *s, FFTComplex *z)
+{
+ int j, np;
+ const uint16_t *revtab = s->revtab;
+ np = 1 << s->nbits;
+ /* TODO: handle split-radix permute in a more optimal way, probably in-place */
+ for(j=0;j<np;j++) s->tmp_buf[revtab[j]] = z[j];
+ memcpy(z, s->tmp_buf, np * sizeof(FFTComplex));
+}
+
+av_cold void ff_fft_end(FFTContext *s)
+{
+ av_freep(&s->revtab);
+ av_freep(&s->tmp_buf);
+}
+
+#define BUTTERFLIES(a0,a1,a2,a3) {\
+ BF(t3, t5, t5, t1);\
+ BF(a2.re, a0.re, a0.re, t5);\
+ BF(a3.im, a1.im, a1.im, t3);\
+ BF(t4, t6, t2, t6);\
+ BF(a3.re, a1.re, a1.re, t4);\
+ BF(a2.im, a0.im, a0.im, t6);\
+}
+
+// force loading all the inputs before storing any.
+// this is slightly slower for small data, but avoids store->load aliasing
+// for addresses separated by large powers of 2.
+#define BUTTERFLIES_BIG(a0,a1,a2,a3) {\
+ FFTSample r0=a0.re, i0=a0.im, r1=a1.re, i1=a1.im;\
+ BF(t3, t5, t5, t1);\
+ BF(a2.re, a0.re, r0, t5);\
+ BF(a3.im, a1.im, i1, t3);\
+ BF(t4, t6, t2, t6);\
+ BF(a3.re, a1.re, r1, t4);\
+ BF(a2.im, a0.im, i0, t6);\
+}
+
+#define TRANSFORM(a0,a1,a2,a3,wre,wim) {\
+ CMUL(t1, t2, a2.re, a2.im, wre, -wim);\
+ CMUL(t5, t6, a3.re, a3.im, wre, wim);\
+ BUTTERFLIES(a0,a1,a2,a3)\
+}
+
+#define TRANSFORM_ZERO(a0,a1,a2,a3) {\
+ t1 = a2.re;\
+ t2 = a2.im;\
+ t5 = a3.re;\
+ t6 = a3.im;\
+ BUTTERFLIES(a0,a1,a2,a3)\
+}
+
+/* z[0...8n-1], w[1...2n-1] */
+#define PASS(name)\
+static void name(FFTComplex *z, const FFTSample *wre, unsigned int n)\
{\
- FFTSample ax, ay, bx, by;\
- bx=pre1;\
- by=pim1;\
- ax=qre1;\
- ay=qim1;\
- pre = (bx + ax);\
- pim = (by + ay);\
- qre = (bx - ax);\
- qim = (by - ay);\
+ FFTDouble t1, t2, t3, t4, t5, t6;\
+ int o1 = 2*n;\
+ int o2 = 4*n;\
+ int o3 = 6*n;\
+ const FFTSample *wim = wre+o1;\
+ n--;\
+\
+ TRANSFORM_ZERO(z[0],z[o1],z[o2],z[o3]);\
+ TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\
+ do {\
+ z += 2;\
+ wre += 2;\
+ wim -= 2;\
+ TRANSFORM(z[0],z[o1],z[o2],z[o3],wre[0],wim[0]);\
+ TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\
+ } while(--n);\
}
-#define MUL16(a,b) ((a) * (b))
+PASS(pass)
+#undef BUTTERFLIES
+#define BUTTERFLIES BUTTERFLIES_BIG
+PASS(pass_big)
-#define CMUL(pre, pim, are, aim, bre, bim) \
+#define DECL_FFT(n,n2,n4)\
+static void fft##n(FFTComplex *z)\
{\
- pre = (MUL16(are, bre) - MUL16(aim, bim));\
- pim = (MUL16(are, bim) + MUL16(bre, aim));\
+ fft##n2(z);\
+ fft##n4(z+n4*2);\
+ fft##n4(z+n4*3);\
+ pass(z,FFT_NAME(ff_cos_##n),n4/2);\
}
-/**
- * Do a complex FFT with the parameters defined in fft_init(). The
- * input data must be permuted before with s->revtab table. No
- * 1.0/sqrt(n) normalization is done.
- */
-void fft_calc_c(FFTContext *s, FFTComplex *z)
+static void fft4(FFTComplex *z)
{
- int ln = s->nbits;
- int j, np, np2;
- int nblocks, nloops;
- register FFTComplex *p, *q;
- FFTComplex *exptab = s->exptab;
- int l;
- FFTSample tmp_re, tmp_im;
-
- np = 1 << ln;
-
- /* pass 0 */
-
- p=&z[0];
- j=(np >> 1);
- do {
- BF(p[0].re, p[0].im, p[1].re, p[1].im,
- p[0].re, p[0].im, p[1].re, p[1].im);
- p+=2;
- } while (--j != 0);
-
- /* pass 1 */
-
-
- p=&z[0];
- j=np >> 2;
- if (s->inverse) {
- do {
- BF(p[0].re, p[0].im, p[2].re, p[2].im,
- p[0].re, p[0].im, p[2].re, p[2].im);
- BF(p[1].re, p[1].im, p[3].re, p[3].im,
- p[1].re, p[1].im, -p[3].im, p[3].re);
- p+=4;
- } while (--j != 0);
- } else {
- do {
- BF(p[0].re, p[0].im, p[2].re, p[2].im,
- p[0].re, p[0].im, p[2].re, p[2].im);
- BF(p[1].re, p[1].im, p[3].re, p[3].im,
- p[1].re, p[1].im, p[3].im, -p[3].re);
- p+=4;
- } while (--j != 0);
- }
- /* pass 2 .. ln-1 */
-
- nblocks = np >> 3;
- nloops = 1 << 2;
- np2 = np >> 1;
- do {
- p = z;
- q = z + nloops;
- for (j = 0; j < nblocks; ++j) {
- BF(p->re, p->im, q->re, q->im,
- p->re, p->im, q->re, q->im);
-
- p++;
- q++;
- for(l = nblocks; l < np2; l += nblocks) {
- CMUL(tmp_re, tmp_im, exptab[l].re, exptab[l].im, q->re, q->im);
- BF(p->re, p->im, q->re, q->im,
- p->re, p->im, tmp_re, tmp_im);
- p++;
- q++;
- }
+ FFTDouble t1, t2, t3, t4, t5, t6, t7, t8;
- p += nloops;
- q += nloops;
- }
- nblocks = nblocks >> 1;
- nloops = nloops << 1;
- } while (nblocks != 0);
+ BF(t3, t1, z[0].re, z[1].re);
+ BF(t8, t6, z[3].re, z[2].re);
+ BF(z[2].re, z[0].re, t1, t6);
+ BF(t4, t2, z[0].im, z[1].im);
+ BF(t7, t5, z[2].im, z[3].im);
+ BF(z[3].im, z[1].im, t4, t8);
+ BF(z[3].re, z[1].re, t3, t7);
+ BF(z[2].im, z[0].im, t2, t5);
}
-/**
- * Do the permutation needed BEFORE calling fft_calc()
- */
-void fft_permute(FFTContext *s, FFTComplex *z)
+static void fft8(FFTComplex *z)
{
- int j, k, np;
- FFTComplex tmp;
- const uint16_t *revtab = s->revtab;
-
- /* reverse */
- np = 1 << s->nbits;
- for(j=0;j<np;j++) {
- k = revtab[j];
- if (k < j) {
- tmp = z[k];
- z[k] = z[j];
- z[j] = tmp;
- }
- }
+ FFTDouble t1, t2, t3, t4, t5, t6;
+
+ fft4(z);
+
+ BF(t1, z[5].re, z[4].re, -z[5].re);
+ BF(t2, z[5].im, z[4].im, -z[5].im);
+ BF(t5, z[7].re, z[6].re, -z[7].re);
+ BF(t6, z[7].im, z[6].im, -z[7].im);
+
+ BUTTERFLIES(z[0],z[2],z[4],z[6]);
+ TRANSFORM(z[1],z[3],z[5],z[7],sqrthalf,sqrthalf);
}
-void fft_end(FFTContext *s)
+#if !CONFIG_SMALL
+static void fft16(FFTComplex *z)
{
- av_freep(&s->revtab);
- av_freep(&s->exptab);
- av_freep(&s->exptab1);
+ FFTDouble t1, t2, t3, t4, t5, t6;
+ FFTSample cos_16_1 = FFT_NAME(ff_cos_16)[1];
+ FFTSample cos_16_3 = FFT_NAME(ff_cos_16)[3];
+
+ fft8(z);
+ fft4(z+8);
+ fft4(z+12);
+
+ TRANSFORM_ZERO(z[0],z[4],z[8],z[12]);
+ TRANSFORM(z[2],z[6],z[10],z[14],sqrthalf,sqrthalf);
+ TRANSFORM(z[1],z[5],z[9],z[13],cos_16_1,cos_16_3);
+ TRANSFORM(z[3],z[7],z[11],z[15],cos_16_3,cos_16_1);
}
+#else
+DECL_FFT(16,8,4)
+#endif
+DECL_FFT(32,16,8)
+DECL_FFT(64,32,16)
+DECL_FFT(128,64,32)
+DECL_FFT(256,128,64)
+DECL_FFT(512,256,128)
+#if !CONFIG_SMALL
+#define pass pass_big
+#endif
+DECL_FFT(1024,512,256)
+DECL_FFT(2048,1024,512)
+DECL_FFT(4096,2048,1024)
+DECL_FFT(8192,4096,2048)
+DECL_FFT(16384,8192,4096)
+DECL_FFT(32768,16384,8192)
+DECL_FFT(65536,32768,16384)
+
+static void (* const fft_dispatch[])(FFTComplex*) = {
+ fft4, fft8, fft16, fft32, fft64, fft128, fft256, fft512, fft1024,
+ fft2048, fft4096, fft8192, fft16384, fft32768, fft65536,
+};
+static void ff_fft_calc_c(FFTContext *s, FFTComplex *z)
+{
+ fft_dispatch[s->nbits-2](z);
+}
projects / ffmpeg / blobdiff