1 files changed, 229 insertions, 0 deletions

diff --git a/apps/codecs/libcook/mdct.c b/apps/codecs/libcook/mdct.c
new file mode 100644
index 0000000000..cb3388f6ff
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+++ b/apps/codecs/libcook/mdct.c
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+/*
+ * MDCT/IMDCT transforms
+ * Copyright (c) 2002 Fabrice Bellard
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include "dsputil.h"
+
+/**
+ * @file libavcodec/mdct.c
+ * MDCT/IMDCT transforms.
+ */
+
+// Generate a Kaiser-Bessel Derived Window.
+#define BESSEL_I0_ITER 50 // default: 50 iterations of Bessel I0 approximation
+av_cold void ff_kbd_window_init(float *window, float alpha, int n)
+{
+   int i, j;
+   double sum = 0.0, bessel, tmp;
+   double local_window[n];
+   double alpha2 = (alpha * M_PI / n) * (alpha * M_PI / n);
+
+   for (i = 0; i < n; i++) {
+       tmp = i * (n - i) * alpha2;
+       bessel = 1.0;
+       for (j = BESSEL_I0_ITER; j > 0; j--)
+           bessel = bessel * tmp / (j * j) + 1;
+       sum += bessel;
+       local_window[i] = sum;
+   }
+
+   sum++;
+   for (i = 0; i < n; i++)
+       window[i] = sqrt(local_window[i] / sum);
+}
+
+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.
+av_cold void ff_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.
+ */
+av_cold int ff_mdct_init(MDCTContext *s, int nbits, int inverse)
+{
+    int n, n4, i;
+    double alpha;
+
+    memset(s, 0, sizeof(*s));
+    n = 1 << nbits;
+    s->nbits = nbits;
+    s->n = n;
+    n4 = n >> 2;
+    s->tcos = av_malloc(n4 * sizeof(FFTSample));
+    if (!s->tcos)
+        goto fail;
+    s->tsin = av_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 (ff_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) \
+{\
+    FFTSample _are = (are);\
+    FFTSample _aim = (aim);\
+    FFTSample _bre = (bre);\
+    FFTSample _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
+ */
+void ff_imdct_half_c(MDCTContext *s, FFTSample *output, const FFTSample *input)
+{
+    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 *)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;
+    }
+    ff_fft_calc(&s->fft, z);
+
+    /* post rotation + reordering */
+    output += n4;
+    for(k = 0; k < n8; k++) {
+        FFTSample 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 inverse MDCT of size N = 2^nbits
+ * @param output N samples
+ * @param input N/2 samples
+ */
+void ff_imdct_calc_c(MDCTContext *s, FFTSample *output, const FFTSample *input)
+{
+    int k;
+    int n = 1 << s->nbits;
+    int n2 = n >> 1;
+    int n4 = n >> 2;
+
+    ff_imdct_half_c(s, output+n4, input);
+
+    for(k = 0; k < n4; k++) {
+        output[k] = -output[n2-k-1];
+        output[n-k-1] = output[n2+k];
+    }
+}
+
+/**
+ * Compute MDCT of size N = 2^nbits
+ * @param input N samples
+ * @param out N/2 samples
+ */
+void ff_mdct_calc(MDCTContext *s, FFTSample *out, const FFTSample *input)
+{
+    int i, j, n, n8, n4, n2, n3;
+    FFTSample re, im;
+    const uint16_t *revtab = s->fft.revtab;
+    const FFTSample *tcos = s->tcos;
+    const FFTSample *tsin = s->tsin;
+    FFTComplex *x = (FFTComplex *)out;
+
+    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]);
+    }
+
+    ff_fft_calc(&s->fft, x);
+
+    /* post rotation */
+    for(i=0;i<n8;i++) {
+        FFTSample r0, i0, r1, i1;
+        CMUL(i1, r0, x[n8-i-1].re, x[n8-i-1].im, -tsin[n8-i-1], -tcos[n8-i-1]);
+        CMUL(i0, r1, x[n8+i  ].re, x[n8+i  ].im, -tsin[n8+i  ], -tcos[n8+i  ]);
+        x[n8-i-1].re = r0;
+        x[n8-i-1].im = i0;
+        x[n8+i  ].re = r1;
+        x[n8+i  ].im = i1;
+    }
+}
+
+av_cold void ff_mdct_end(MDCTContext *s)
+{
+    av_freep(&s->tcos);
+    av_freep(&s->tsin);
+    ff_fft_end(&s->fft);
+}