--- /dev/null
+/*
+ * FFT/IFFT transforms.
+ *
+ * Extracted 2009 from mplayer 2009-02-10 libavcodec/fft.c and libavcodec/mdct.c
+ *
+ * Copyright (c) 2008 Loren Merritt
+ * Copyright (c) 2002 Fabrice Bellard
+ * Partly based on libdjbfft by D. J. Bernstein
+ *
+ * Licensed under the GNU Lesser General Public License.
+ * For licencing details see COPYING.LIB.
+ */
+
+/**
+ * \file fft.c FFT/MDCT transforms.
+ */
+
+#include <inttypes.h>
+#include <math.h>
+#include <string.h>
+#include <stdlib.h>
+#include <regex.h>
+
+#include "para.h"
+#include "error.h"
+#include "string.h"
+#include "mdct.h"
+#include "wma.h"
+
+typedef float fftsample_t;
+
+#define DECLARE_ALIGNED(n,t,v) t v __attribute__ ((aligned (n)))
+#define DECLARE_ALIGNED_16(t, v) DECLARE_ALIGNED(16, t, v)
+#define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */
+
+struct fft_complex {
+ fftsample_t re, im;
+};
+
+struct fft_context {
+ int nbits;
+ int inverse;
+ uint16_t *revtab;
+ struct fft_complex *exptab;
+ struct fft_complex *exptab1; /* only used by SSE code */
+ struct fft_complex *tmp_buf;
+};
+
+struct mdct_context {
+ /** Size of MDCT (i.e. number of input data * 2). */
+ int n;
+ /** n = 2^n bits. */
+ int nbits;
+ /** pre/post rotation tables */
+ fftsample_t *tcos;
+ fftsample_t *tsin;
+ struct fft_context fft;
+};
+
+/* cos(2*pi*x/n) for 0<=x<=n/4, followed by its reverse */
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_16[8]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_32[16]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_64[32]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_128[64]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_256[128]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_512[256]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_1024[512]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_2048[1024]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_4096[2048]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_8192[4096]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_16384[8192]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_32768[16384]);
+DECLARE_ALIGNED_16(fftsample_t, ff_cos_65536[32768]);
+
+static fftsample_t *ff_cos_tabs[] = {
+ ff_cos_16, ff_cos_32, ff_cos_64, ff_cos_128, ff_cos_256,
+ ff_cos_512, ff_cos_1024, ff_cos_2048, ff_cos_4096, ff_cos_8192,
+ ff_cos_16384, ff_cos_32768, ff_cos_65536,
+};
+
+static int split_radix_permutation(int i, int n, int inverse)
+{
+ 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;
+}
+
+#define sqrthalf (float)M_SQRT1_2
+
+#define BF(x,y,a,b) {\
+ x = a - b;\
+ y = a + b;\
+}
+
+#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_t 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) {\
+ t1 = a2.re * wre + a2.im * wim;\
+ t2 = a2.im * wre - a2.re * wim;\
+ t5 = a3.re * wre - a3.im * wim;\
+ t6 = a3.im * wre + a3.re * 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(struct fft_complex *z, const fftsample_t *wre, unsigned int n)\
+{\
+ fftsample_t t1, t2, t3, t4, t5, t6;\
+ int o1 = 2*n;\
+ int o2 = 4*n;\
+ int o3 = 6*n;\
+ const fftsample_t *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);\
+}
+
+PASS(pass)
+#undef BUTTERFLIES
+#define BUTTERFLIES BUTTERFLIES_BIG
+
+#define DECL_FFT(n,n2,n4)\
+static void fft##n(struct fft_complex *z)\
+{\
+ fft##n2(z);\
+ fft##n4(z+n4*2);\
+ fft##n4(z+n4*3);\
+ pass(z,ff_cos_##n,n4/2);\
+}
+static void fft4(struct fft_complex *z)
+{
+ fftsample_t t1, t2, t3, t4, t5, t6, t7, t8;
+
+ 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);
+}
+
+static void fft8(struct fft_complex *z)
+{
+ fftsample_t t1, t2, t3, t4, t5, t6, t7, t8;
+
+ 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(t3, z[7].re, z[6].re, -z[7].re);
+ BF(t4, z[7].im, z[6].im, -z[7].im);
+ BF(t8, t1, t3, t1);
+ BF(t7, t2, t2, t4);
+ BF(z[4].re, z[0].re, z[0].re, t1);
+ BF(z[4].im, z[0].im, z[0].im, t2);
+ BF(z[6].re, z[2].re, z[2].re, t7);
+ BF(z[6].im, z[2].im, z[2].im, t8);
+
+ TRANSFORM(z[1], z[3], z[5], z[7], sqrthalf, sqrthalf);
+}
+
+static void fft16(struct fft_complex *z)
+{
+ fftsample_t t1, t2, t3, t4, t5, t6;
+
+ 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], ff_cos_16[1], ff_cos_16[3]);
+ TRANSFORM(z[3], z[7], z[11], z[15], ff_cos_16[3], ff_cos_16[1]);
+}
+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)
+
+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 (*fft_dispatch[]) (struct fft_complex *) =
+{
+ fft4, fft8, fft16, fft32, fft64, fft128, fft256, fft512, fft1024,
+ fft2048, fft4096, fft8192, fft16384, fft32768, fft65536,
+};
+
+static void fft(struct fft_context *s, struct fft_complex *z)
+{
+ fft_dispatch[s->nbits - 2] (z);
+}
+
+/* complex multiplication: p = a * b */
+#define CMUL(pre, pim, are, aim, bre, bim) \
+{\
+ fftsample_t _are = (are);\
+ fftsample_t _aim = (aim);\
+ fftsample_t _bre = (bre);\
+ fftsample_t _bim = (bim);\
+ (pre) = _are * _bre - _aim * _bim;\
+ (pim) = _are * _bim + _aim * _bre;\
+}
+
+/**
+ * Compute the middle half of the inverse MDCT of size N = 2^nbits
+ *
+ * Thus excluding the parts that can be derived by symmetry.
+ *
+ * \param output N/2 samples.
+ * \param input N/2 samples.
+ */
+static void imdct_half(struct mdct_context *s, fftsample_t *output,
+ const fftsample_t *input)
+{
+ int k, n8, n4, n2, n, j;
+ const uint16_t *revtab = s->fft.revtab;
+ const fftsample_t *tcos = s->tcos;
+ const fftsample_t *tsin = s->tsin;
+ const fftsample_t *in1, *in2;
+ struct fft_complex *z = (struct fft_complex *)output;
+
+ 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(&s->fft, z);
+
+ /* post rotation + reordering */
+ output += n4;
+ for (k = 0; k < n8; k++) {
+ fftsample_t r0, i0, r1, i1;
+ CMUL(r0, i1, z[n8 - k - 1].im, z[n8 - k - 1].re,
+ tsin[n8 - k - 1], tcos[n8 - k - 1]);
+ CMUL(r1, i0, z[n8 + k].im, z[n8 + k].re, tsin[n8 + k],
+ tcos[n8 + k]);
+ z[n8 - k - 1].re = r0;
+ z[n8 - k - 1].im = i0;
+ z[n8 + k].re = r1;
+ z[n8 + k].im = i1;
+ }
+}
+
+/**
+ * Compute the inverse MDCT of size N = 2^nbits.
+ *
+ * \param output N samples.
+ * \param input N/2 samples.
+ */
+void imdct(struct mdct_context *s, float *output, const float *input)
+{
+ int k;
+ int n = 1 << s->nbits;
+ int n2 = n >> 1;
+ int n4 = n >> 2;
+
+ imdct_half(s, output + n4, input);
+
+ for (k = 0; k < n4; k++) {
+ output[k] = -output[n2 - k - 1];
+ output[n - k - 1] = output[n2 + k];
+ }
+}
+
+static int fft_init(struct fft_context *s, int nbits, int inverse)
+{
+ int i, j, m, n;
+ float alpha, c1, s1, s2;
+ int split_radix = 1;
+
+ if (nbits < 2 || nbits > 16)
+ return -E_FFT_BAD_PARAMS;
+ s->nbits = nbits;
+ n = 1 << nbits;
+
+ s->tmp_buf = NULL;
+ s->exptab = para_malloc((n / 2) * sizeof(struct fft_complex));
+ s->revtab = para_malloc(n * sizeof(uint16_t));
+ s->inverse = inverse;
+
+ s2 = inverse ? 1.0 : -1.0;
+
+ s->exptab1 = NULL;
+
+ if (split_radix) {
+ for (j = 4; j <= nbits; j++) {
+ int k = 1 << j;
+ double freq = 2 * M_PI / k;
+ fftsample_t *tab = ff_cos_tabs[j - 4];
+ for (i = 0; i <= k / 4; i++)
+ tab[i] = cos(i * freq);
+ for (i = 1; i < k / 4; i++)
+ tab[k / 2 - i] = tab[i];
+ }
+ for (i = 0; i < n; i++)
+ s->revtab[-split_radix_permutation(
+ i, n, s->inverse) & (n - 1)] = i;
+ s->tmp_buf = para_malloc(n * sizeof(struct fft_complex));
+ } else {
+ int np, nblocks, np2, l;
+ struct fft_complex *q;
+
+ 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;
+ }
+
+ np = 1 << nbits;
+ nblocks = np >> 3;
+ np2 = np >> 1;
+ s->exptab1 = para_malloc(np * 2 * sizeof(struct fft_complex));
+ 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);
+ freep(&s->exptab);
+
+ /* 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;
+}
+
+static void fft_end(struct fft_context *ctx)
+{
+ freep(&ctx->revtab);
+ freep(&ctx->exptab);
+ freep(&ctx->exptab1);
+ freep(&ctx->tmp_buf);
+}
+
+DECLARE_ALIGNED(16, float, ff_sine_128[128]);
+DECLARE_ALIGNED(16, float, ff_sine_256[256]);
+DECLARE_ALIGNED(16, float, ff_sine_512[512]);
+DECLARE_ALIGNED(16, float, ff_sine_1024[1024]);
+DECLARE_ALIGNED(16, float, ff_sine_2048[2048]);
+DECLARE_ALIGNED(16, float, ff_sine_4096[4096]);
+
+float *ff_sine_windows[6] = {
+ ff_sine_128, ff_sine_256, ff_sine_512, ff_sine_1024,
+ ff_sine_2048, ff_sine_4096
+};
+
+// Generate a sine window.
+void sine_window_init(float *window, int n)
+{
+ int i;
+
+ for (i = 0; i < n; i++)
+ window[i] = sinf((i + 0.5) * (M_PI / (2.0 * n)));
+}
+
+/**
+ * Init MDCT or IMDCT computation.
+ */
+int mdct_init(int nbits, int inverse, struct mdct_context **result)
+{
+ int ret, n, n4, i;
+ double alpha;
+ struct mdct_context *s;
+
+ s = para_malloc(sizeof(*s));
+ memset(s, 0, sizeof(*s));
+ n = 1 << nbits;
+ s->nbits = nbits;
+ s->n = n;
+ n4 = n >> 2;
+ s->tcos = para_malloc(n4 * sizeof(fftsample_t));
+ s->tsin = para_malloc(n4 * sizeof(fftsample_t));
+
+ 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);
+ }
+ ret = fft_init(&s->fft, s->nbits - 2, inverse);
+ if (ret < 0)
+ goto fail;
+ *result = s;
+ return 0;
+fail:
+ freep(&s->tcos);
+ freep(&s->tsin);
+ free(s);
+ return ret;
+}
+
+void mdct_end(struct mdct_context *ctx)
+{
+ freep(&ctx->tcos);
+ freep(&ctx->tsin);
+ fft_end(&ctx->fft);
+ free(ctx);
+}
projects / paraslash.git / blobdiff