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libavcodec: Implementation of 32 bit fixed point FFT

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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>
This commit is contained in:
Nedeljko Babic
2013-06-03 16:11:12 +02:00
committed by Michael Niedermayer
parent 27cc3e72f8
commit 18d7074b4e
19 changed files with 543 additions and 36 deletions
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21
libavcodec/fft-internal.h
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@@ -36,12 +36,29 @@
#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 SCALE_FLOAT(a, bits) lrint((a) * (double)(1 << (bits)))
#define FIX15(a) av_clip(SCALE_FLOAT(a, 15), -32767, 32767)
#define sqrthalf ((int16_t)((1<<15)*M_SQRT1_2))
@@ -62,6 +79,8 @@ void ff_mdct_calcw_c(FFTContext *s, FFTDouble *output, const FFTSample *input);
#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)