Rename ffmpeg-4.2-fit to ffmpeg-4-fit

trunk/3rdparty/ffmpeg-4-fit/libavcodec/mdct_template.c

@@ -0,0 +1,213 @@
+/*
+ * 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 <stdlib.h>
+#include <string.h>
+#include "libavutil/common.h"
+#include "libavutil/libm.h"
+#include "libavutil/mathematics.h"
+#include "fft.h"
+#include "fft-internal.h"
+
+/**
+ * @file
+ * MDCT/IMDCT transforms.
+ */
+
+#if FFT_FLOAT
+#   define RSCALE(x, y) ((x) + (y))
+#else
+#if FFT_FIXED_32
+#   define RSCALE(x, y) ((int)((x) + (unsigned)(y) + 32) >> 6)
+#else /* FFT_FIXED_32 */
+#   define RSCALE(x, y) ((int)((x) + (unsigned)(y)) >> 1)
+#endif /* FFT_FIXED_32 */
+#endif
+
+/**
+ * init MDCT or IMDCT computation.
+ */
+av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
+{
+    int n, n4, i;
+    double alpha, theta;
+    int tstep;
+
+    memset(s, 0, sizeof(*s));
+    n = 1 << nbits;
+    s->mdct_bits = nbits;
+    s->mdct_size = n;
+    n4 = n >> 2;
+    s->mdct_permutation = FF_MDCT_PERM_NONE;
+
+    if (ff_fft_init(s, s->mdct_bits - 2, inverse) < 0)
+        goto fail;
+
+    s->tcos = av_malloc_array(n/2, sizeof(FFTSample));
+    if (!s->tcos)
+        goto fail;
+
+    switch (s->mdct_permutation) {
+    case FF_MDCT_PERM_NONE:
+        s->tsin = s->tcos + n4;
+        tstep = 1;
+        break;
+    case FF_MDCT_PERM_INTERLEAVE:
+        s->tsin = s->tcos + 1;
+        tstep = 2;
+        break;
+    default:
+        goto fail;
+    }
+
+    theta = 1.0 / 8.0 + (scale < 0 ? n4 : 0);
+    scale = sqrt(fabs(scale));
+    for(i=0;i<n4;i++) {
+        alpha = 2 * M_PI * (i + theta) / n;
+#if FFT_FIXED_32
+        s->tcos[i*tstep] = lrint(-cos(alpha) * 2147483648.0);
+        s->tsin[i*tstep] = lrint(-sin(alpha) * 2147483648.0);
+#else
+        s->tcos[i*tstep] = FIX15(-cos(alpha) * scale);
+        s->tsin[i*tstep] = FIX15(-sin(alpha) * scale);
+#endif
+    }
+    return 0;
+ fail:
+    ff_mdct_end(s);
+    return -1;
+}
+
+/**
+ * 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(FFTContext *s, FFTSample *output, const FFTSample *input)
+{
+    int k, n8, n4, n2, n, j;
+    const uint16_t *revtab = s->revtab;
+    const FFTSample *tcos = s->tcos;
+    const FFTSample *tsin = s->tsin;
+    const FFTSample *in1, *in2;
+    FFTComplex *z = (FFTComplex *)output;
+
+    n = 1 << s->mdct_bits;
+    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;
+    }
+    s->fft_calc(s, z);
+
+    /* post rotation + reordering */
+    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(FFTContext *s, FFTSample *output, const FFTSample *input)
+{
+    int k;
+    int n = 1 << s->mdct_bits;
+    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_c(FFTContext *s, FFTSample *out, const FFTSample *input)
+{
+    int i, j, n, n8, n4, n2, n3;
+    FFTDouble re, im;
+    const uint16_t *revtab = s->revtab;
+    const FFTSample *tcos = s->tcos;
+    const FFTSample *tsin = s->tsin;
+    FFTComplex *x = (FFTComplex *)out;
+
+    n = 1 << s->mdct_bits;
+    n2 = n >> 1;
+    n4 = n >> 2;
+    n8 = n >> 3;
+    n3 = 3 * n4;
+
+    /* pre rotation */
+    for(i=0;i<n8;i++) {
+        re = RSCALE(-input[2*i+n3], - input[n3-1-2*i]);
+        im = RSCALE(-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 = RSCALE( input[2*i]   , - input[n2-1-2*i]);
+        im = RSCALE(-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]);
+    }
+
+    s->fft_calc(s, 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(FFTContext *s)
+{
+    av_freep(&s->tcos);
+    ff_fft_end(s);
+}