09c2d08c
 Hu Chunming
arm交付版
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/*
* Copyright (c) 2011 Mans Rullgard
*
* 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 "config.h"
#include "libavutil/attributes.h"
#include "libavutil/thread.h"
#include "mpegaudio.h"
#include "mpegaudiodsp.h"
#include "dct.h"
#include "dct32.h"
static AVOnce mpadsp_table_init = AV_ONCE_INIT;
static av_cold void mpadsp_init_tabs(void)
{
int i, j;
/* compute mdct windows */
for (i = 0; i < 36; i++) {
for (j = 0; j < 4; j++) {
double d;
if (j == 2 && i % 3 != 1)
continue;
d = sin(M_PI * (i + 0.5) / 36.0);
if (j == 1) {
if (i >= 30) d = 0;
else if (i >= 24) d = sin(M_PI * (i - 18 + 0.5) / 12.0);
else if (i >= 18) d = 1;
} else if (j == 3) {
if (i < 6) d = 0;
else if (i < 12) d = sin(M_PI * (i - 6 + 0.5) / 12.0);
else if (i < 18) d = 1;
}
//merge last stage of imdct into the window coefficients
d *= 0.5 * IMDCT_SCALAR / cos(M_PI * (2 * i + 19) / 72);
if (j == 2) {
ff_mdct_win_float[j][i/3] = d / (1 << 5);
ff_mdct_win_fixed[j][i/3] = d / (1 << 5) * (1LL << 32) + 0.5;
} else {
int idx = i < 18 ? i : i + (MDCT_BUF_SIZE/2 - 18);
ff_mdct_win_float[j][idx] = d / (1 << 5);
ff_mdct_win_fixed[j][idx] = d / (1 << 5) * (1LL << 32) + 0.5;
}
}
}
/* NOTE: we do frequency inversion after the MDCT by changing
the sign of the right window coefs */
for (j = 0; j < 4; j++) {
for (i = 0; i < MDCT_BUF_SIZE; i += 2) {
ff_mdct_win_float[j + 4][i ] = ff_mdct_win_float[j][i ];
ff_mdct_win_float[j + 4][i + 1] = -ff_mdct_win_float[j][i + 1];
ff_mdct_win_fixed[j + 4][i ] = ff_mdct_win_fixed[j][i ];
ff_mdct_win_fixed[j + 4][i + 1] = -ff_mdct_win_fixed[j][i + 1];
}
}
if (ARCH_X86)
ff_mpadsp_init_x86_tabs();
}
av_cold void ff_mpadsp_init(MPADSPContext *s)
{
DCTContext dct;
ff_dct_init(&dct, 5, DCT_II);
ff_thread_once(&mpadsp_table_init, &mpadsp_init_tabs);
s->apply_window_float = ff_mpadsp_apply_window_float;
s->apply_window_fixed = ff_mpadsp_apply_window_fixed;
s->dct32_float = dct.dct32;
s->dct32_fixed = ff_dct32_fixed;
s->imdct36_blocks_float = ff_imdct36_blocks_float;
s->imdct36_blocks_fixed = ff_imdct36_blocks_fixed;
if (ARCH_AARCH64) ff_mpadsp_init_aarch64(s);
if (ARCH_ARM) ff_mpadsp_init_arm(s);
if (ARCH_PPC) ff_mpadsp_init_ppc(s);
if (ARCH_X86) ff_mpadsp_init_x86(s);
if (HAVE_MIPSFPU) ff_mpadsp_init_mipsfpu(s);
if (HAVE_MIPSDSP) ff_mpadsp_init_mipsdsp(s);
}
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