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authorKlaus Schmidinger <vdr@tvdr.de>2001-08-09 11:41:39 +0200
committerKlaus Schmidinger <vdr@tvdr.de>2001-08-09 11:41:39 +0200
commitc50dc5e888627bd1644f46585a44dc118c865127 (patch)
tree1dc5a28da106e3404863fc0234891142a5c29b2f /ac3dec/imdct_c.c
parent85a027791063dfd7e94ccef45ea9e755df63d29a (diff)
downloadvdr-c50dc5e888627bd1644f46585a44dc118c865127.tar.gz
vdr-c50dc5e888627bd1644f46585a44dc118c865127.tar.bz2
Improvements from Matjaz Thaler
Diffstat (limited to 'ac3dec/imdct_c.c')
-rw-r--r--ac3dec/imdct_c.c218
1 files changed, 218 insertions, 0 deletions
diff --git a/ac3dec/imdct_c.c b/ac3dec/imdct_c.c
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+++ b/ac3dec/imdct_c.c
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+/*
+ * imdct.c
+ *
+ * Copyright (C) Aaron Holtzman - May 1999
+ *
+ * This file is part of ac3dec, a free Dolby AC-3 stream decoder.
+ *
+ * ac3dec is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * ac3dec 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Make; see the file COPYING. If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ *
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+#include "ac3.h"
+#include "ac3_internal.h"
+
+#include "downmix.h"
+#include "imdct_c.h"
+#include "srfft.h"
+
+
+#define N 512
+
+extern void (*imdct_do_512) (float data[],float delay[]);
+extern void (*imdct_do_512_nol) (float data[], float delay[]);
+extern void (*fft_64p) (complex_t *);
+
+extern const int pm128[];
+extern float window[];
+extern complex_t buf[128];
+
+extern void fft_64p_c (complex_t *);
+extern void fft_128p_c (complex_t *);
+
+static void imdct_do_512_c (float data[],float delay[]);
+static void imdct_do_512_nol_c (float data[], float delay[]);
+
+/* Twiddle factors for IMDCT */
+static float xcos1[128] __attribute__((aligned(16)));
+static float xsin1[128] __attribute__((aligned(16)));
+
+
+int imdct_init_c (void)
+{
+ int i;
+ float scale = 255.99609372;
+
+ imdct_do_512 = imdct_do_512_c;
+ imdct_do_512_nol = imdct_do_512_nol_c;
+ fft_64p = fft_64p_c;
+
+ /* Twiddle factors to turn IFFT into IMDCT */
+
+ for (i=0; i < 128; i++) {
+ xcos1[i] = cos(2.0f * M_PI * (8*i+1)/(8*N)) * scale;
+ xsin1[i] = sin(2.0f * M_PI * (8*i+1)/(8*N)) * scale;
+ }
+
+ return 0;
+}
+
+
+static void imdct_do_512_c (float data[], float delay[])
+{
+ int i, j;
+ float tmp_a_r, tmp_a_i;
+ float *data_ptr;
+ float *delay_ptr;
+ float *window_ptr;
+
+// 512 IMDCT with source and dest data in 'data'
+// Pre IFFT complex multiply plus IFFT complex conjugate
+
+ for( i=0; i < 128; i++) {
+ j = pm128[i];
+ //a = (data[256-2*j-1] - data[2*j]) * (xcos1[j] + xsin1[j]);
+ //c = data[2*j] * xcos1[j];
+ //b = data[256-2*j-1] * xsin1[j];
+ //buf1[i].re = a - b + c;
+ //buf1[i].im = b + c;
+ buf[i].re = (data[256-2*j-1] * xcos1[j]) - (data[2*j] * xsin1[j]);
+ buf[i].im = -1.0 * (data[2*j] * xcos1[j] + data[256-2*j-1] * xsin1[j]);
+ }
+
+ fft_128p_c (&buf[0]);
+
+// Post IFFT complex multiply plus IFFT complex conjugate
+ for (i=0; i < 128; i++) {
+ tmp_a_r = buf[i].re;
+ tmp_a_i = buf[i].im;
+ //a = (tmp_a_r - tmp_a_i) * (xcos1[j] + xsin1[j]);
+ //b = tmp_a_r * xsin1[j];
+ //c = tmp_a_i * xcos1[j];
+ //buf[j].re = a - b + c;
+ //buf[j].im = b + c;
+ buf[i].re =(tmp_a_r * xcos1[i]) + (tmp_a_i * xsin1[i]);
+ buf[i].im =(tmp_a_r * xsin1[i]) - (tmp_a_i * xcos1[i]);
+ }
+
+ data_ptr = data;
+ delay_ptr = delay;
+ window_ptr = window;
+
+// Window and convert to real valued signal
+ for (i=0; i< 64; i++) {
+ *data_ptr++ = -buf[64+i].im * *window_ptr++ + *delay_ptr++;
+ *data_ptr++ = buf[64-i-1].re * *window_ptr++ + *delay_ptr++;
+ }
+
+ for(i=0; i< 64; i++) {
+ *data_ptr++ = -buf[i].re * *window_ptr++ + *delay_ptr++;
+ *data_ptr++ = buf[128-i-1].im * *window_ptr++ + *delay_ptr++;
+ }
+
+// The trailing edge of the window goes into the delay line
+ delay_ptr = delay;
+
+ for(i=0; i< 64; i++) {
+ *delay_ptr++ = -buf[64+i].re * *--window_ptr;
+ *delay_ptr++ = buf[64-i-1].im * *--window_ptr;
+ }
+
+ for(i=0; i<64; i++) {
+ *delay_ptr++ = buf[i].im * *--window_ptr;
+ *delay_ptr++ = -buf[128-i-1].re * *--window_ptr;
+ }
+}
+
+
+static void imdct_do_512_nol_c (float data[], float delay[])
+{
+ int i, j;
+
+ float tmp_a_i;
+ float tmp_a_r;
+
+ float *data_ptr;
+ float *delay_ptr;
+ float *window_ptr;
+
+ //
+ // 512 IMDCT with source and dest data in 'data'
+ //
+
+ // Pre IFFT complex multiply plus IFFT cmplx conjugate
+
+ for( i=0; i < 128; i++) {
+ /* z[i] = (X[256-2*i-1] + j * X[2*i]) * (xcos1[i] + j * xsin1[i]) */
+ j = pm128[i];
+ //a = (data[256-2*j-1] - data[2*j]) * (xcos1[j] + xsin1[j]);
+ //c = data[2*j] * xcos1[j];
+ //b = data[256-2*j-1] * xsin1[j];
+ //buf1[i].re = a - b + c;
+
+ //buf1[i].im = b + c;
+ buf[i].re = (data[256-2*j-1] * xcos1[j]) - (data[2*j] * xsin1[j]);
+ buf[i].im = -1.0 * (data[2*j] * xcos1[j] + data[256-2*j-1] * xsin1[j]);
+ }
+
+ fft_128p_c (&buf[0]);
+
+ /* Post IFFT complex multiply plus IFFT complex conjugate*/
+ for (i=0; i < 128; i++) {
+ /* y[n] = z[n] * (xcos1[n] + j * xsin1[n]) ; */
+ /* int j1 = i; */
+ tmp_a_r = buf[i].re;
+ tmp_a_i = buf[i].im;
+ //a = (tmp_a_r - tmp_a_i) * (xcos1[j] + xsin1[j]);
+ //b = tmp_a_r * xsin1[j];
+ //c = tmp_a_i * xcos1[j];
+ //buf[j].re = a - b + c;
+ //buf[j].im = b + c;
+ buf[i].re =(tmp_a_r * xcos1[i]) + (tmp_a_i * xsin1[i]);
+ buf[i].im =(tmp_a_r * xsin1[i]) - (tmp_a_i * xcos1[i]);
+ }
+
+ data_ptr = data;
+ delay_ptr = delay;
+ window_ptr = window;
+
+ /* Window and convert to real valued signal, no overlap here*/
+ for (i=0; i< 64; i++) {
+ *data_ptr++ = -buf[64+i].im * *window_ptr++;
+ *data_ptr++ = buf[64-i-1].re * *window_ptr++;
+ }
+
+ for(i=0; i< 64; i++) {
+ *data_ptr++ = -buf[i].re * *window_ptr++;
+ *data_ptr++ = buf[128-i-1].im * *window_ptr++;
+ }
+
+ /* The trailing edge of the window goes into the delay line */
+ delay_ptr = delay;
+
+ for(i=0; i< 64; i++) {
+ *delay_ptr++ = -buf[64+i].re * *--window_ptr;
+ *delay_ptr++ = buf[64-i-1].im * *--window_ptr;
+ }
+
+ for(i=0; i<64; i++) {
+ *delay_ptr++ = buf[i].im * *--window_ptr;
+ *delay_ptr++ = -buf[128-i-1].re * *--window_ptr;
+ }
+}