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FFmpeg/libavcodec/fft-internal.h
Nedeljko Babic 18d7074b4e libavcodec: Implementation of 32 bit fixed point FFT
Iterative implementation of 32 bit fixed point split-radix FFT.
Max FFT that can be calculated currently is 2^12.

Signed-off-by: Nedeljko Babic <nbabic@mips.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2013-08-04 14:01:41 +02:00

95 lines
3.2 KiB
C

/*
* 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
*/
#ifndef AVCODEC_FFT_INTERNAL_H
#define AVCODEC_FFT_INTERNAL_H
#if CONFIG_FFT_FLOAT
#define FIX15(v) (v)
#define sqrthalf (float)M_SQRT1_2
#define BF(x, y, a, b) do { \
x = a - b; \
y = a + b; \
} while (0)
#define CMUL(dre, dim, are, aim, bre, bim) do { \
(dre) = (are) * (bre) - (aim) * (bim); \
(dim) = (are) * (bim) + (aim) * (bre); \
} while (0)
#else
#define SCALE_FLOAT(a, bits) lrint((a) * (double)(1 << (bits)))
#if CONFIG_FFT_FIXED_32
#define CMUL(dre, dim, are, aim, bre, bim) do { \
int64_t accu; \
(accu) = (int64_t)(bre) * (are); \
(accu) -= (int64_t)(bim) * (aim); \
(dre) = (int)(((accu) + 0x40000000) >> 31); \
(accu) = (int64_t)(bre) * (aim); \
(accu) += (int64_t)(bim) * (are); \
(dim) = (int)(((accu) + 0x40000000) >> 31); \
} while (0)
#define FIX15(a) av_clip(SCALE_FLOAT(a, 31), -2147483647, 2147483647)
#else /* CONFIG_FFT_FIXED_32 */
#include "fft.h"
#include "mathops.h"
void ff_mdct_calcw_c(FFTContext *s, FFTDouble *output, const FFTSample *input);
#define FIX15(a) av_clip(SCALE_FLOAT(a, 15), -32767, 32767)
#define sqrthalf ((int16_t)((1<<15)*M_SQRT1_2))
#define BF(x, y, a, b) do { \
x = (a - b) >> 1; \
y = (a + b) >> 1; \
} while (0)
#define CMULS(dre, dim, are, aim, bre, bim, sh) do { \
(dre) = (MUL16(are, bre) - MUL16(aim, bim)) >> sh; \
(dim) = (MUL16(are, bim) + MUL16(aim, bre)) >> sh; \
} while (0)
#define CMUL(dre, dim, are, aim, bre, bim) \
CMULS(dre, dim, are, aim, bre, bim, 15)
#define CMULL(dre, dim, are, aim, bre, bim) \
CMULS(dre, dim, are, aim, bre, bim, 0)
#endif /* CONFIG_FFT_FIXED_32 */
#endif /* CONFIG_FFT_FLOAT */
#define ff_imdct_calc_c FFT_NAME(ff_imdct_calc_c)
#define ff_imdct_half_c FFT_NAME(ff_imdct_half_c)
#define ff_mdct_calc_c FFT_NAME(ff_mdct_calc_c)
void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input);
void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input);
void ff_mdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input);
#endif /* AVCODEC_FFT_INTERNAL_H */