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-rw-r--r--libavcodec/dsputil.h49
-rw-r--r--libavcodec/fft-test.c294
-rw-r--r--libavcodec/fft.c229
-rw-r--r--libavcodec/i386/fft_sse.c128
-rw-r--r--libavcodec/mdct.c170
5 files changed, 869 insertions, 1 deletions
diff --git a/libavcodec/dsputil.h b/libavcodec/dsputil.h
index a8285c80b6..096dc288c6 100644
--- a/libavcodec/dsputil.h
+++ b/libavcodec/dsputil.h
@@ -221,5 +221,52 @@ struct unaligned_32 { uint32_t l; } __attribute__((packed));
void get_psnr(UINT8 *orig_image[3], UINT8 *coded_image[3],
int orig_linesize[3], int coded_linesize,
AVCodecContext *avctx);
-
+
+/* FFT computation */
+
+/* NOTE: soon integer code will be added, so you must use the
+ FFTSample type */
+typedef float FFTSample;
+
+typedef struct FFTComplex {
+ FFTSample re, im;
+} FFTComplex;
+
+typedef struct FFTContext {
+ int nbits;
+ int inverse;
+ uint16_t *revtab;
+ FFTComplex *exptab;
+ FFTComplex *exptab1; /* only used by SSE code */
+ void (*fft_calc)(struct FFTContext *s, FFTComplex *z);
+} FFTContext;
+
+int fft_init(FFTContext *s, int nbits, int inverse);
+void fft_permute(FFTContext *s, FFTComplex *z);
+void fft_calc_c(FFTContext *s, FFTComplex *z);
+void fft_calc_sse(FFTContext *s, FFTComplex *z);
+static inline void fft_calc(FFTContext *s, FFTComplex *z)
+{
+ s->fft_calc(s, z);
+}
+void fft_end(FFTContext *s);
+
+/* MDCT computation */
+
+typedef struct MDCTContext {
+ int n; /* size of MDCT (i.e. number of input data * 2) */
+ int nbits; /* n = 2^nbits */
+ /* pre/post rotation tables */
+ FFTSample *tcos;
+ FFTSample *tsin;
+ FFTContext fft;
+} MDCTContext;
+
+int mdct_init(MDCTContext *s, int nbits, int inverse);
+void imdct_calc(MDCTContext *s, FFTSample *output,
+ const FFTSample *input, FFTSample *tmp);
+void mdct_calc(MDCTContext *s, FFTSample *out,
+ const FFTSample *input, FFTSample *tmp);
+void mdct_end(MDCTContext *s);
+
#endif
diff --git a/libavcodec/fft-test.c b/libavcodec/fft-test.c
new file mode 100644
index 0000000000..3015c7a709
--- /dev/null
+++ b/libavcodec/fft-test.c
@@ -0,0 +1,294 @@
+/* FFT and MDCT tests */
+#include "dsputil.h"
+#include <math.h>
+#include <getopt.h>
+#include <sys/time.h>
+
+int mm_flags;
+
+void *av_malloc(int size)
+{
+ void *ptr;
+ ptr = malloc(size);
+ return ptr;
+}
+
+void av_free(void *ptr)
+{
+ /* XXX: this test should not be needed on most libcs */
+ if (ptr)
+ free(ptr);
+}
+
+/* cannot call it directly because of 'void **' casting is not automatic */
+void __av_freep(void **ptr)
+{
+ av_free(*ptr);
+ *ptr = NULL;
+}
+
+/* reference fft */
+
+#define MUL16(a,b) ((a) * (b))
+
+#define CMAC(pre, pim, are, aim, bre, bim) \
+{\
+ pre += (MUL16(are, bre) - MUL16(aim, bim));\
+ pim += (MUL16(are, bim) + MUL16(bre, aim));\
+}
+
+FFTComplex *exptab;
+
+void fft_ref_init(int nbits, int inverse)
+{
+ int n, i;
+ float c1, s1, alpha;
+
+ n = 1 << nbits;
+ exptab = av_malloc((n / 2) * sizeof(FFTComplex));
+
+ for(i=0;i<(n/2);i++) {
+ alpha = 2 * M_PI * (float)i / (float)n;
+ c1 = cos(alpha);
+ s1 = sin(alpha);
+ if (!inverse)
+ s1 = -s1;
+ exptab[i].re = c1;
+ exptab[i].im = s1;
+ }
+}
+
+void fft_ref(FFTComplex *tabr, FFTComplex *tab, int nbits)
+{
+ int n, i, j, k, n2;
+ float tmp_re, tmp_im, s, c;
+ FFTComplex *q;
+
+ n = 1 << nbits;
+ n2 = n >> 1;
+ for(i=0;i<n;i++) {
+ tmp_re = 0;
+ tmp_im = 0;
+ q = tab;
+ for(j=0;j<n;j++) {
+ k = (i * j) & (n - 1);
+ if (k >= n2) {
+ c = -exptab[k - n2].re;
+ s = -exptab[k - n2].im;
+ } else {
+ c = exptab[k].re;
+ s = exptab[k].im;
+ }
+ CMAC(tmp_re, tmp_im, c, s, q->re, q->im);
+ q++;
+ }
+ tabr[i].re = tmp_re;
+ tabr[i].im = tmp_im;
+ }
+}
+
+void imdct_ref(float *out, float *in, int n)
+{
+ int k, i, a;
+ float sum, f;
+
+ for(i=0;i<n;i++) {
+ sum = 0;
+ for(k=0;k<n/2;k++) {
+ a = (2 * i + 1 + (n / 2)) * (2 * k + 1);
+ f = cos(M_PI * a / (double)(2 * n));
+ sum += f * in[k];
+ }
+ out[i] = -sum;
+ }
+}
+
+/* NOTE: no normalisation by 1 / N is done */
+void mdct_ref(float *output, float *input, int n)
+{
+ int k, i;
+ float a, s;
+
+ /* do it by hand */
+ for(k=0;k<n/2;k++) {
+ s = 0;
+ for(i=0;i<n;i++) {
+ a = (2*M_PI*(2*i+1+n/2)*(2*k+1) / (4 * n));
+ s += input[i] * cos(a);
+ }
+ output[k] = s;
+ }
+}
+
+
+float frandom(void)
+{
+ return (float)((random() & 0xffff) - 32768) / 32768.0;
+}
+
+INT64 gettime(void)
+{
+ struct timeval tv;
+ gettimeofday(&tv,NULL);
+ return (INT64)tv.tv_sec * 1000000 + tv.tv_usec;
+}
+
+void check_diff(float *tab1, float *tab2, int n)
+{
+ int i;
+
+ for(i=0;i<n;i++) {
+ if (fabsf(tab1[i] - tab2[i]) >= 1e-3) {
+ printf("ERROR %d: %f %f\n",
+ i, tab1[i], tab2[i]);
+ }
+ }
+}
+
+
+void help(void)
+{
+ printf("usage: fft-test [-h] [-s] [-i] [-n b]\n"
+ "-h print this help\n"
+ "-s speed test\n"
+ "-m (I)MDCT test\n"
+ "-i inverse transform test\n"
+ "-n b set the transform size to 2^b\n"
+ );
+ exit(1);
+}
+
+
+
+int main(int argc, char **argv)
+{
+ FFTComplex *tab, *tab1, *tab_ref;
+ FFTSample *tabtmp, *tab2;
+ int it, i, c;
+ int do_speed = 0;
+ int do_mdct = 0;
+ int do_inverse = 0;
+ FFTContext s1, *s = &s1;
+ MDCTContext m1, *m = &m1;
+ int fft_nbits, fft_size;
+
+ mm_flags = 0;
+ fft_nbits = 9;
+ for(;;) {
+ c = getopt(argc, argv, "hsimn:");
+ if (c == -1)
+ break;
+ switch(c) {
+ case 'h':
+ help();
+ break;
+ case 's':
+ do_speed = 1;
+ break;
+ case 'i':
+ do_inverse = 1;
+ break;
+ case 'm':
+ do_mdct = 1;
+ break;
+ case 'n':
+ fft_nbits = atoi(optarg);
+ break;
+ }
+ }
+
+ fft_size = 1 << fft_nbits;
+ tab = av_malloc(fft_size * sizeof(FFTComplex));
+ tab1 = av_malloc(fft_size * sizeof(FFTComplex));
+ tab_ref = av_malloc(fft_size * sizeof(FFTComplex));
+ tabtmp = av_malloc(fft_size / 2 * sizeof(FFTSample));
+ tab2 = av_malloc(fft_size * sizeof(FFTSample));
+
+ if (do_mdct) {
+ if (do_inverse)
+ printf("IMDCT");
+ else
+ printf("MDCT");
+ mdct_init(m, fft_nbits, do_inverse);
+ } else {
+ if (do_inverse)
+ printf("IFFT");
+ else
+ printf("FFT");
+ fft_init(s, fft_nbits, do_inverse);
+ fft_ref_init(fft_nbits, do_inverse);
+ }
+ printf(" %d test\n", fft_size);
+
+ /* generate random data */
+
+ for(i=0;i<fft_size;i++) {
+ tab1[i].re = frandom();
+ tab1[i].im = frandom();
+ }
+
+ /* checking result */
+ printf("Checking...\n");
+
+ if (do_mdct) {
+ if (do_inverse) {
+ imdct_ref((float *)tab_ref, (float *)tab1, fft_size);
+ imdct_calc(m, tab2, (float *)tab1, tabtmp);
+ check_diff((float *)tab_ref, tab2, fft_size);
+ } else {
+ mdct_ref((float *)tab_ref, (float *)tab1, fft_size);
+
+ mdct_calc(m, tab2, (float *)tab1, tabtmp);
+
+ check_diff((float *)tab_ref, tab2, fft_size / 2);
+ }
+ } else {
+ memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
+ fft_permute(s, tab);
+ fft_calc(s, tab);
+
+ fft_ref(tab_ref, tab1, fft_nbits);
+ check_diff((float *)tab_ref, (float *)tab, fft_size * 2);
+ }
+
+ /* do a speed test */
+
+ if (do_speed) {
+ INT64 time_start, duration;
+ int nb_its;
+
+ printf("Speed test...\n");
+ /* we measure during about 1 seconds */
+ nb_its = 1;
+ for(;;) {
+ time_start = gettime();
+ for(it=0;it<nb_its;it++) {
+ if (do_mdct) {
+ if (do_inverse) {
+ imdct_calc(m, (float *)tab, (float *)tab1, tabtmp);
+ } else {
+ mdct_calc(m, (float *)tab, (float *)tab1, tabtmp);
+ }
+ } else {
+ memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
+ fft_calc(s, tab);
+ }
+ }
+ duration = gettime() - time_start;
+ if (duration >= 1000000)
+ break;
+ nb_its *= 2;
+ }
+ printf("time: %0.1f us/transform [total time=%0.2f s its=%d]\n",
+ (double)duration / nb_its,
+ (double)duration / 1000000.0,
+ nb_its);
+ }
+
+ if (do_mdct) {
+ mdct_end(m);
+ } else {
+ fft_end(s);
+ }
+ return 0;
+}
diff --git a/libavcodec/fft.c b/libavcodec/fft.c
new file mode 100644
index 0000000000..0f5181ac3c
--- /dev/null
+++ b/libavcodec/fft.c
@@ -0,0 +1,229 @@
+/*
+ * FFT/IFFT transforms
+ * Copyright (c) 2002 Fabrice Bellard.
+ *
+ * This library 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.
+ *
+ * This library 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
+ */
+#include "dsputil.h"
+
+/**
+ * The size of the FFT is 2^nbits. If inverse is TRUE, inverse FFT is
+ * done
+ */
+int fft_init(FFTContext *s, int nbits, int inverse)
+{
+ int i, j, m, n;
+ float alpha, c1, s1, s2;
+
+ 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->inverse = inverse;
+
+ 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) && 0
+ if (mm_flags & MM_SSE) {
+ 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);
+ }
+#endif
+
+ /* compute bit reverse table */
+
+ for(i=0;i<n;i++) {
+ m=0;
+ for(j=0;j<nbits;j++) {
+ m |= ((i >> j) & 1) << (nbits-j-1);
+ }
+ s->revtab[i]=m;
+ }
+ return 0;
+ fail:
+ av_freep(&s->revtab);
+ av_freep(&s->exptab);
+ av_freep(&s->exptab1);
+ return -1;
+}
+
+/* butter fly op */
+#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
+{\
+ 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);\
+}
+
+#define MUL16(a,b) ((a) * (b))
+
+#define CMUL(pre, pim, are, aim, bre, bim) \
+{\
+ pre = (MUL16(are, bre) - MUL16(aim, bim));\
+ pim = (MUL16(are, bim) + MUL16(bre, aim));\
+}
+
+/**
+ * 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)
+{
+ 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++;
+ }
+
+ p += nloops;
+ q += nloops;
+ }
+ nblocks = nblocks >> 1;
+ nloops = nloops << 1;
+ } while (nblocks != 0);
+}
+
+/**
+ * Do the permutation needed BEFORE calling fft_calc()
+ */
+void fft_permute(FFTContext *s, 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;
+ }
+ }
+}
+
+void fft_end(FFTContext *s)
+{
+ av_freep(&s->revtab);
+ av_freep(&s->exptab);
+ av_freep(&s->exptab1);
+}
+
diff --git a/libavcodec/i386/fft_sse.c b/libavcodec/i386/fft_sse.c
new file mode 100644
index 0000000000..8e8e36b0f7
--- /dev/null
+++ b/libavcodec/i386/fft_sse.c
@@ -0,0 +1,128 @@
+/*
+ * FFT/MDCT transform with SSE optimizations
+ * Copyright (c) 2002 Fabrice Bellard.
+ *
+ * This library 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.
+ *
+ * This library 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
+ */
+#include "../dsputil.h"
+#include <math.h>
+
+#include <xmmintrin.h>
+
+static const float p1p1p1m1[4] __attribute__((aligned(16))) =
+ { 1.0, 1.0, 1.0, -1.0 };
+
+static const float p1p1m1m1[4] __attribute__((aligned(16))) =
+ { 1.0, 1.0, -1.0, -1.0 };
+
+#if 0
+static void print_v4sf(const char *str, __m128 a)
+{
+ float *p = (float *)&a;
+ printf("%s: %f %f %f %f\n",
+ str, p[0], p[1], p[2], p[3]);
+}
+#endif
+
+/* XXX: handle reverse case */
+void fft_calc_sse(FFTContext *s, FFTComplex *z)
+{
+ int ln = s->nbits;
+ int j, np, np2;
+ int nblocks, nloops;
+ register FFTComplex *p, *q;
+ FFTComplex *cptr, *cptr1;
+ int k;
+
+ np = 1 << ln;
+
+ {
+ __m128 *r, a, b, a1, c1, c2;
+
+ r = (__m128 *)&z[0];
+ c1 = *(__m128 *)p1p1m1m1;
+ c2 = *(__m128 *)p1p1p1m1;
+ j = (np >> 2);
+ do {
+ a = r[0];
+ b = _mm_shuffle_ps(a, a, _MM_SHUFFLE(1, 0, 3, 2));
+ a = _mm_mul_ps(a, c1);
+ /* do the pass 0 butterfly */
+ a = _mm_add_ps(a, b);
+
+ a1 = r[1];
+ b = _mm_shuffle_ps(a1, a1, _MM_SHUFFLE(1, 0, 3, 2));
+ a1 = _mm_mul_ps(a1, c1);
+ /* do the pass 0 butterfly */
+ b = _mm_add_ps(a1, b);
+
+ /* multiply third by -i */
+ b = _mm_shuffle_ps(b, b, _MM_SHUFFLE(2, 3, 1, 0));
+ b = _mm_mul_ps(b, c2);
+
+ /* do the pass 1 butterfly */
+ r[0] = _mm_add_ps(a, b);
+ r[1] = _mm_sub_ps(a, b);
+ r += 2;
+ } while (--j != 0);
+ }
+ /* pass 2 .. ln-1 */
+
+ nblocks = np >> 3;
+ nloops = 1 << 2;
+ np2 = np >> 1;
+
+ cptr1 = s->exptab1;
+ do {
+ p = z;
+ q = z + nloops;
+ j = nblocks;
+ do {
+ cptr = cptr1;
+ k = nloops >> 1;
+ do {
+ __m128 a, b, c, t1, t2;
+
+ a = *(__m128 *)p;
+ b = *(__m128 *)q;
+
+ /* complex mul */
+ c = *(__m128 *)cptr;
+ /* cre*re cim*re */
+ t1 = _mm_mul_ps(c,
+ _mm_shuffle_ps(b, b, _MM_SHUFFLE(2, 2, 0, 0)));
+ c = *(__m128 *)(cptr + 2);
+ /* -cim*im cre*im */
+ t2 = _mm_mul_ps(c,
+ _mm_shuffle_ps(b, b, _MM_SHUFFLE(3, 3, 1, 1)));
+ b = _mm_add_ps(t1, t2);
+
+ /* butterfly */
+ *(__m128 *)p = _mm_add_ps(a, b);
+ *(__m128 *)q = _mm_sub_ps(a, b);
+
+ p += 2;
+ q += 2;
+ cptr += 4;
+ } while (--k);
+
+ p += nloops;
+ q += nloops;
+ } while (--j);
+ cptr1 += nloops * 2;
+ nblocks = nblocks >> 1;
+ nloops = nloops << 1;
+ } while (nblocks != 0);
+}
diff --git a/libavcodec/mdct.c b/libavcodec/mdct.c
new file mode 100644
index 0000000000..baab5d3152
--- /dev/null
+++ b/libavcodec/mdct.c
@@ -0,0 +1,170 @@
+/*
+ * MDCT/IMDCT transforms
+ * Copyright (c) 2002 Fabrice Bellard.
+ *
+ * This library 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.
+ *
+ * This library 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
+ */
+#include "dsputil.h"
+
+/*
+ * init MDCT or IMDCT computation
+ */
+int mdct_init(MDCTContext *s, int nbits, int inverse)
+{
+ int n, n4, i;
+ float alpha;
+
+ memset(s, 0, sizeof(*s));
+ n = 1 << nbits;
+ s->nbits = nbits;
+ s->n = n;
+ n4 = n >> 2;
+ s->tcos = malloc(n4 * sizeof(FFTSample));
+ if (!s->tcos)
+ goto fail;
+ s->tsin = malloc(n4 * sizeof(FFTSample));
+ if (!s->tsin)
+ goto fail;
+
+ for(i=0;i<n4;i++) {
+ alpha = 2 * M_PI * (i + 1.0 / 8.0) / n;
+ s->tcos[i] = -cos(alpha);
+ s->tsin[i] = -sin(alpha);
+ }
+ if (fft_init(&s->fft, s->nbits - 2, inverse) < 0)
+ goto fail;
+ return 0;
+ fail:
+ av_freep(&s->tcos);
+ av_freep(&s->tsin);
+ return -1;
+}
+
+/* complex multiplication: p = a * b */
+#define CMUL(pre, pim, are, aim, bre, bim) \
+{\
+ float _are = (are);\
+ float _aim = (aim);\
+ float _bre = (bre);\
+ float _bim = (bim);\
+ (pre) = _are * _bre - _aim * _bim;\
+ (pim) = _are * _bim + _aim * _bre;\
+}
+
+/**
+ * Compute inverse MDCT of size N = 2^nbits
+ * @param output N samples
+ * @param input N/2 samples
+ * @param tmp N/2 samples
+ */
+void imdct_calc(MDCTContext *s, FFTSample *output,
+ const FFTSample *input, FFTSample *tmp)
+{
+ int k, n8, n4, n2, n, j;
+ const uint16_t *revtab = s->fft.revtab;
+ const FFTSample *tcos = s->tcos;
+ const FFTSample *tsin = s->tsin;
+ const FFTSample *in1, *in2;
+ FFTComplex *z = (FFTComplex *)tmp;
+
+ n = 1 << s->nbits;
+ n2 = n >> 1;
+ n4 = n >> 2;
+ n8 = n >> 3;
+
+ /* pre rotation */
+ in1 = input;
+ in2 = input + n2 - 1;
+ for(k = 0; k < n4; k++) {
+ j=revtab[k];
+ CMUL(z[j].re, z[j].im, *in2, *in1, tcos[k], tsin[k]);
+ in1 += 2;
+ in2 -= 2;
+ }
+ fft_calc(&s->fft, z);
+
+ /* post rotation + reordering */
+ /* XXX: optimize */
+ for(k = 0; k < n4; k++) {
+ CMUL(z[k].re, z[k].im, z[k].re, z[k].im, tcos[k], tsin[k]);
+ }
+ for(k = 0; k < n8; k++) {
+ output[2*k] = -z[n8 + k].im;
+ output[n2-1-2*k] = z[n8 + k].im;
+
+ output[2*k+1] = z[n8-1-k].re;
+ output[n2-1-2*k-1] = -z[n8-1-k].re;
+
+ output[n2 + 2*k]=-z[k+n8].re;
+ output[n-1- 2*k]=-z[k+n8].re;
+
+ output[n2 + 2*k+1]=z[n8-k-1].im;
+ output[n-2 - 2 * k] = z[n8-k-1].im;
+ }
+}
+
+/**
+ * Compute MDCT of size N = 2^nbits
+ * @param input N samples
+ * @param out N/2 samples
+ * @param tmp temporary storage of N/2 samples
+ */
+void mdct_calc(MDCTContext *s, FFTSample *out,
+ const FFTSample *input, FFTSample *tmp)
+{
+ int i, j, n, n8, n4, n2, n3;
+ FFTSample re, im, re1, im1;
+ const uint16_t *revtab = s->fft.revtab;
+ const FFTSample *tcos = s->tcos;
+ const FFTSample *tsin = s->tsin;
+ FFTComplex *x = (FFTComplex *)tmp;
+
+ n = 1 << s->nbits;
+ n2 = n >> 1;
+ n4 = n >> 2;
+ n8 = n >> 3;
+ n3 = 3 * n4;
+
+ /* pre rotation */
+ for(i=0;i<n8;i++) {
+ re = -input[2*i+3*n4] - input[n3-1-2*i];
+ im = -input[n4+2*i] + input[n4-1-2*i];
+ j = revtab[i];
+ CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]);
+
+ re = input[2*i] - input[n2-1-2*i];
+ im = -(input[n2+2*i] + input[n-1-2*i]);
+ j = revtab[n8 + i];
+ CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]);
+ }
+
+ fft_calc(&s->fft, x);
+
+ /* post rotation */
+ for(i=0;i<n4;i++) {
+ re = x[i].re;
+ im = x[i].im;
+ CMUL(re1, im1, re, im, -tsin[i], -tcos[i]);
+ out[2*i] = im1;
+ out[n2-1-2*i] = re1;
+ }
+}
+
+void mdct_end(MDCTContext *s)
+{
+ av_freep(&s->tcos);
+ av_freep(&s->tsin);
+ fft_end(&s->fft);
+}
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