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91e1625db1
INT32_MAX (2147483647) isn't exactly representable by a floating point value, with the closest being 2147483648.0. So when rescaling a value of 1.0, this could overflow when casting the 64-bit value returned from lrintf() into 32 bits. Unfortunately the properties of integer overflows don't match up well with how a Fourier Transform operates. So clip the value before casting to a 32-bit int. Should be noted we don't have overflows with the table values we're currently using. However, converting a Kaiser-Bessel window function with a length of 256 and a parameter of 5.0 to fixed point did create overflows. So this is more of insurance to save debugging time in case something changes in the future. The macro is only used during init, so it being a little slower is not a problem.
156 lines
5.7 KiB
C
156 lines
5.7 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 AVUTIL_TX_PRIV_H
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#define AVUTIL_TX_PRIV_H
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#include "tx.h"
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#include <stddef.h>
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#include "thread.h"
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#include "mem.h"
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#include "mem_internal.h"
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#include "avassert.h"
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#include "attributes.h"
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#ifdef TX_FLOAT
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#define TX_NAME(x) x ## _float
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#define SCALE_TYPE float
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typedef float FFTSample;
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typedef AVComplexFloat FFTComplex;
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#elif defined(TX_DOUBLE)
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#define TX_NAME(x) x ## _double
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#define SCALE_TYPE double
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typedef double FFTSample;
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typedef AVComplexDouble FFTComplex;
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#elif defined(TX_INT32)
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#define TX_NAME(x) x ## _int32
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#define SCALE_TYPE float
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typedef int32_t FFTSample;
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typedef AVComplexInt32 FFTComplex;
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#else
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typedef void FFTComplex;
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#endif
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#if defined(TX_FLOAT) || defined(TX_DOUBLE)
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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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#define SMUL(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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#define RESCALE(x) (x)
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#define FOLD(a, b) ((a) + (b))
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#elif defined(TX_INT32)
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/* Properly rounds the result */
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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)(bim) * (are); \
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(accu) += (int64_t)(bre) * (aim); \
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(dim) = (int)(((accu) + 0x40000000) >> 31); \
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} while (0)
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#define SMUL(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)(bim) * (are); \
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(accu) -= (int64_t)(bre) * (aim); \
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(dim) = (int)(((accu) + 0x40000000) >> 31); \
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} while (0)
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#define RESCALE(x) (av_clip64(lrintf((x) * 2147483648.0), INT32_MIN, INT32_MAX))
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#define FOLD(x, y) ((int)((x) + (unsigned)(y) + 32) >> 6)
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#endif
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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 CMUL3(c, a, b) \
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CMUL((c).re, (c).im, (a).re, (a).im, (b).re, (b).im)
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#define COSTABLE(size) \
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DECLARE_ALIGNED(32, FFTSample, TX_NAME(ff_cos_##size))[size/2]
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/* Used by asm, reorder with care */
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struct AVTXContext {
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int n; /* Nptwo part */
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int m; /* Ptwo part */
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int inv; /* Is inverted */
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int type; /* Type */
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FFTComplex *exptab; /* MDCT exptab */
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FFTComplex *tmp; /* Temporary buffer needed for all compound transforms */
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int *pfatab; /* Input/Output mapping for compound transforms */
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int *revtab; /* Input mapping for power of two transforms */
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};
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/* Shared functions */
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int ff_tx_type_is_mdct(enum AVTXType type);
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int ff_tx_gen_compound_mapping(AVTXContext *s);
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int ff_tx_gen_ptwo_revtab(AVTXContext *s);
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/* Also used by SIMD init */
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static inline int split_radix_permutation(int i, int n, int inverse)
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{
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int m;
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if (n <= 2)
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return i & 1;
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m = n >> 1;
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if (!(i & m))
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return split_radix_permutation(i, m, inverse)*2;
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m >>= 1;
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if (inverse == !(i & m))
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return split_radix_permutation(i, m, inverse)*4 + 1;
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else
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return split_radix_permutation(i, m, inverse)*4 - 1;
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}
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/* Templated functions */
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int ff_tx_init_mdct_fft_float(AVTXContext *s, av_tx_fn *tx,
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enum AVTXType type, int inv, int len,
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const void *scale, uint64_t flags);
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int ff_tx_init_mdct_fft_double(AVTXContext *s, av_tx_fn *tx,
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enum AVTXType type, int inv, int len,
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const void *scale, uint64_t flags);
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int ff_tx_init_mdct_fft_int32(AVTXContext *s, av_tx_fn *tx,
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enum AVTXType type, int inv, int len,
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const void *scale, uint64_t flags);
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typedef struct CosTabsInitOnce {
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void (*func)(void);
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AVOnce control;
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} CosTabsInitOnce;
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#endif /* AVUTIL_TX_PRIV_H */
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