* Copyright (c) 2010 Alex Converse <alex.converse@gmail.com>
* Copyright (c) 2010 Vitor Sessak
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * 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 2.1 of the License, or (at your option) any later version.
*
- * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
- * @file libavcodec/dct.c
+ * @file
* (Inverse) Discrete Cosine Transforms. These are also known as the
* type II and type III DCTs respectively.
*/
#include <math.h>
+#include <string.h>
+
#include "libavutil/mathematics.h"
-#include "fft.h"
+#include "dct.h"
+#include "dct32.h"
-/* sin((M_PI * x / (2*n)) */
-#define SIN(s,n,x) (s->costab[(n) - (x)])
+/* sin((M_PI * x / (2 * n)) */
+#define SIN(s, n, x) (s->costab[(n) - (x)])
-/* cos((M_PI * x / (2*n)) */
-#define COS(s,n,x) (s->costab[x])
+/* cos((M_PI * x / (2 * n)) */
+#define COS(s, n, x) (s->costab[x])
-static void ff_dct_calc_III_c(DCTContext *ctx, FFTSample *data)
+static void dst_calc_I_c(DCTContext *ctx, FFTSample *data)
{
int n = 1 << ctx->nbits;
int i;
- float next = data[n - 1];
- float inv_n = 1.0f / n;
+ data[0] = 0;
+ for (i = 1; i < n / 2; i++) {
+ float tmp1 = data[i ];
+ float tmp2 = data[n - i];
+ float s = SIN(ctx, n, 2 * i);
- for (i = n - 2; i >= 2; i -= 2) {
- float val1 = data[i ];
- float val2 = data[i - 1] - data[i + 1];
- float c = COS(ctx, n, i);
- float s = SIN(ctx, n, i);
+ s *= tmp1 + tmp2;
+ tmp1 = (tmp1 - tmp2) * 0.5f;
+ data[i] = s + tmp1;
+ data[n - i] = s - tmp1;
+ }
- data[i ] = c * val1 + s * val2;
- data[i + 1] = s * val1 - c * val2;
- }
+ data[n / 2] *= 2;
+ ctx->rdft.rdft_calc(&ctx->rdft, data);
- data[1] = 2 * next;
+ data[0] *= 0.5f;
+
+ for (i = 1; i < n - 2; i += 2) {
+ data[i + 1] += data[i - 1];
+ data[i] = -data[i + 2];
+ }
- ff_rdft_calc(&ctx->rdft, data);
+ data[n - 1] = 0;
+}
- for (i = 0; i < n / 2; i++) {
- float tmp1 = data[i ] * inv_n;
- float tmp2 = data[n - i - 1] * inv_n;
- float csc = ctx->csc2[i] * (tmp1 - tmp2);
+static void dct_calc_I_c(DCTContext *ctx, FFTSample *data)
+{
+ int n = 1 << ctx->nbits;
+ int i;
+ float next = -0.5f * (data[0] - data[n]);
- tmp1 += tmp2;
- data[i ] = tmp1 + csc;
- data[n - i - 1] = tmp1 - csc;
- }
+ for (i = 0; i < n / 2; i++) {
+ float tmp1 = data[i];
+ float tmp2 = data[n - i];
+ float s = SIN(ctx, n, 2 * i);
+ float c = COS(ctx, n, 2 * i);
+
+ c *= tmp1 - tmp2;
+ s *= tmp1 - tmp2;
+
+ next += c;
+
+ tmp1 = (tmp1 + tmp2) * 0.5f;
+ data[i] = tmp1 - s;
+ data[n - i] = tmp1 + s;
+ }
+
+ ctx->rdft.rdft_calc(&ctx->rdft, data);
+ data[n] = data[1];
+ data[1] = next;
+
+ for (i = 3; i <= n; i += 2)
+ data[i] = data[i - 2] - data[i];
}
-static void ff_dct_calc_II_c(DCTContext *ctx, FFTSample *data)
+static void dct_calc_III_c(DCTContext *ctx, FFTSample *data)
{
int n = 1 << ctx->nbits;
int i;
- float next;
- for (i=0; i < n/2; i++) {
- float tmp1 = data[i ];
- float tmp2 = data[n - i - 1];
- float s = SIN(ctx, n, 2*i + 1);
- s *= tmp1 - tmp2;
- tmp1 = (tmp1 + tmp2) * 0.5f;
+ float next = data[n - 1];
+ float inv_n = 1.0f / n;
- data[i ] = tmp1 + s;
- data[n-i-1] = tmp1 - s;
- }
+ for (i = n - 2; i >= 2; i -= 2) {
+ float val1 = data[i];
+ float val2 = data[i - 1] - data[i + 1];
+ float c = COS(ctx, n, i);
+ float s = SIN(ctx, n, i);
- ff_rdft_calc(&ctx->rdft, data);
+ data[i] = c * val1 + s * val2;
+ data[i + 1] = s * val1 - c * val2;
+ }
- next = data[1] * 0.5;
- data[1] *= -1;
+ data[1] = 2 * next;
- for (i = n - 2; i >= 0; i -= 2) {
- float inr = data[i ];
- float ini = data[i + 1];
- float c = COS(ctx, n, i);
- float s = SIN(ctx, n, i);
+ ctx->rdft.rdft_calc(&ctx->rdft, data);
- data[i ] = c * inr + s * ini;
+ for (i = 0; i < n / 2; i++) {
+ float tmp1 = data[i] * inv_n;
+ float tmp2 = data[n - i - 1] * inv_n;
+ float csc = ctx->csc2[i] * (tmp1 - tmp2);
- data[i+1] = next;
+ tmp1 += tmp2;
+ data[i] = tmp1 + csc;
+ data[n - i - 1] = tmp1 - csc;
+ }
+}
- next += s * inr - c * ini;
- }
+static void dct_calc_II_c(DCTContext *ctx, FFTSample *data)
+{
+ int n = 1 << ctx->nbits;
+ int i;
+ float next;
+
+ for (i = 0; i < n / 2; i++) {
+ float tmp1 = data[i];
+ float tmp2 = data[n - i - 1];
+ float s = SIN(ctx, n, 2 * i + 1);
+
+ s *= tmp1 - tmp2;
+ tmp1 = (tmp1 + tmp2) * 0.5f;
+
+ data[i] = tmp1 + s;
+ data[n-i-1] = tmp1 - s;
+ }
+
+ ctx->rdft.rdft_calc(&ctx->rdft, data);
+
+ next = data[1] * 0.5;
+ data[1] *= -1;
+
+ for (i = n - 2; i >= 0; i -= 2) {
+ float inr = data[i ];
+ float ini = data[i + 1];
+ float c = COS(ctx, n, i);
+ float s = SIN(ctx, n, i);
+
+ data[i] = c * inr + s * ini;
+ data[i + 1] = next;
+
+ next += s * inr - c * ini;
+ }
}
-void ff_dct_calc(DCTContext *s, FFTSample *data)
+static void dct32_func(DCTContext *ctx, FFTSample *data)
{
- s->dct_calc(s, data);
+ ctx->dct32(data, data);
}
-av_cold int ff_dct_init(DCTContext *s, int nbits, int inverse)
+av_cold int ff_dct_init(DCTContext *s, int nbits, enum DCTTransformType inverse)
{
int n = 1 << nbits;
int i;
- s->nbits = nbits;
- s->inverse = inverse;
+ memset(s, 0, sizeof(*s));
- ff_init_ff_cos_tabs(nbits+2);
+ s->nbits = nbits;
+ s->inverse = inverse;
- s->costab = ff_cos_tabs[nbits+2];
+ if (inverse == DCT_II && nbits == 5) {
+ s->dct_calc = dct32_func;
+ } else {
+ ff_init_ff_cos_tabs(nbits + 2);
- s->csc2 = av_malloc(n/2 * sizeof(FFTSample));
+ s->costab = ff_cos_tabs[nbits + 2];
+ s->csc2 = av_malloc(n / 2 * sizeof(FFTSample));
+ if (!s->csc2)
+ return AVERROR(ENOMEM);
- if (ff_rdft_init(&s->rdft, nbits, inverse) < 0) {
- av_free(s->csc2);
- return -1;
- }
+ if (ff_rdft_init(&s->rdft, nbits, inverse == DCT_III) < 0) {
+ av_free(s->csc2);
+ return -1;
+ }
+
+ for (i = 0; i < n / 2; i++)
+ s->csc2[i] = 0.5 / sin((M_PI / (2 * n) * (2 * i + 1)));
- for (i = 0; i < n/2; i++)
- s->csc2[i] = 0.5 / sin((M_PI / (2*n) * (2*i + 1)));
+ switch (inverse) {
+ case DCT_I : s->dct_calc = dct_calc_I_c; break;
+ case DCT_II : s->dct_calc = dct_calc_II_c; break;
+ case DCT_III: s->dct_calc = dct_calc_III_c; break;
+ case DST_I : s->dct_calc = dst_calc_I_c; break;
+ }
+ }
- if(inverse) {
- s->dct_calc = ff_dct_calc_III_c;
- } else
- s->dct_calc = ff_dct_calc_II_c;
+ s->dct32 = ff_dct32_float;
+ if (ARCH_X86)
+ ff_dct_init_x86(s);
return 0;
}
projects / ffmpeg / blobdiff