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![Nedeljko Babic](/assets/img/avatar_default.png)
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>
95 lines
3.2 KiB
C
95 lines
3.2 KiB
C
/*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVCODEC_FFT_INTERNAL_H
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#define AVCODEC_FFT_INTERNAL_H
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#if CONFIG_FFT_FLOAT
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#define FIX15(v) (v)
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#define sqrthalf (float)M_SQRT1_2
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#define BF(x, y, a, b) do { \
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x = a - b; \
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y = a + b; \
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} while (0)
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#define CMUL(dre, dim, are, aim, bre, bim) do { \
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(dre) = (are) * (bre) - (aim) * (bim); \
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(dim) = (are) * (bim) + (aim) * (bre); \
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} while (0)
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#else
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#define SCALE_FLOAT(a, bits) lrint((a) * (double)(1 << (bits)))
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#if CONFIG_FFT_FIXED_32
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#define CMUL(dre, dim, are, aim, bre, bim) do { \
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int64_t accu; \
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(accu) = (int64_t)(bre) * (are); \
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(accu) -= (int64_t)(bim) * (aim); \
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(dre) = (int)(((accu) + 0x40000000) >> 31); \
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(accu) = (int64_t)(bre) * (aim); \
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(accu) += (int64_t)(bim) * (are); \
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(dim) = (int)(((accu) + 0x40000000) >> 31); \
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} while (0)
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#define FIX15(a) av_clip(SCALE_FLOAT(a, 31), -2147483647, 2147483647)
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#else /* CONFIG_FFT_FIXED_32 */
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#include "fft.h"
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#include "mathops.h"
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void ff_mdct_calcw_c(FFTContext *s, FFTDouble *output, const FFTSample *input);
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#define FIX15(a) av_clip(SCALE_FLOAT(a, 15), -32767, 32767)
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#define sqrthalf ((int16_t)((1<<15)*M_SQRT1_2))
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#define BF(x, y, a, b) do { \
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x = (a - b) >> 1; \
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y = (a + b) >> 1; \
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} while (0)
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#define CMULS(dre, dim, are, aim, bre, bim, sh) do { \
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(dre) = (MUL16(are, bre) - MUL16(aim, bim)) >> sh; \
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(dim) = (MUL16(are, bim) + MUL16(aim, bre)) >> sh; \
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} while (0)
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#define CMUL(dre, dim, are, aim, bre, bim) \
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CMULS(dre, dim, are, aim, bre, bim, 15)
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#define CMULL(dre, dim, are, aim, bre, bim) \
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CMULS(dre, dim, are, aim, bre, bim, 0)
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#endif /* CONFIG_FFT_FIXED_32 */
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#endif /* CONFIG_FFT_FLOAT */
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#define ff_imdct_calc_c FFT_NAME(ff_imdct_calc_c)
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#define ff_imdct_half_c FFT_NAME(ff_imdct_half_c)
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#define ff_mdct_calc_c FFT_NAME(ff_mdct_calc_c)
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void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input);
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void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input);
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void ff_mdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input);
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#endif /* AVCODEC_FFT_INTERNAL_H */
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