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Fixed-point FFT and MDCT

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This commit is contained in:
Mans Rullgard
2011-03-26 15:20:30 +00:00
parent 2f97b12eaf
commit 7087ce08c8
10 changed files with 257 additions and 52 deletions
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10
libavcodec/Makefile
View File

@@ -31,15 +31,16 @@ OBJS-$(CONFIG_ENCODERS) += faandct.o jfdctfst.o jfdctint.o
OBJS-$(CONFIG_DCT) += dct.o
OBJS-$(CONFIG_DWT) += dwt.o
OBJS-$(CONFIG_DXVA2) += dxva2.o
FFT-OBJS-$(CONFIG_HARDCODED_TABLES) += cos_tables.o
OBJS-$(CONFIG_FFT) += avfft.o fft.o $(FFT-OBJS-yes)
FFT-OBJS-$(CONFIG_HARDCODED_TABLES) += cos_tables.o cos_fixed_tables.o
OBJS-$(CONFIG_FFT) += avfft.o fft_fixed.o fft_float.o \
$(FFT-OBJS-yes)
OBJS-$(CONFIG_GOLOMB) += golomb.o
OBJS-$(CONFIG_H264DSP) += h264dsp.o h264idct.o
OBJS-$(CONFIG_H264PRED) += h264pred.o
OBJS-$(CONFIG_HUFFMAN) += huffman.o
OBJS-$(CONFIG_LPC) += lpc.o
OBJS-$(CONFIG_LSP) += lsp.o
OBJS-$(CONFIG_MDCT) += mdct.o
OBJS-$(CONFIG_MDCT) += mdct_fixed.o mdct_float.o
RDFT-OBJS-$(CONFIG_HARDCODED_TABLES) += sin_tables.o
OBJS-$(CONFIG_RDFT) += rdft.o $(RDFT-OBJS-yes)
OBJS-$(CONFIG_SINEWIN) += sinewin.o
@@ -672,6 +673,9 @@ $(SUBDIR)dct-test$(EXESUF): $(SUBDIR)dctref.o
$(SUBDIR)cos_tables.c: $(SUBDIR)costablegen$(HOSTEXESUF)
$(M)./$< > $@
$(SUBDIR)cos_fixed_tables.c: $(SUBDIR)costablegen$(HOSTEXESUF)
$(M)./$< cos fixed > $@
$(SUBDIR)sin_tables.c: $(SUBDIR)costablegen$(HOSTEXESUF)
$(M)./$< sin > $@

26
libavcodec/costablegen.c
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@@ -29,14 +29,33 @@
#endif
#define BITS 16
#define FLOATFMT "%.18e"
#define FIXEDFMT "%6d"
static int clip_f15(int v)
{
return v < -32767 ? -32767 :
v > 32767 ? 32767 :
v;
}
static void printval(double val, int fixed)
{
if (fixed)
printf(" "FIXEDFMT",", clip_f15(lrint(val * (double)(1<<15))));
else
printf(" "FLOATFMT",", val);
}
int main(int argc, char *argv[])
{
int i, j;
int do_sin = argc == 2 && !strcmp(argv[1], "sin");
int do_sin = argc > 1 && !strcmp(argv[1], "sin");
int fixed = argc > 2 && !strcmp(argv[2], "fixed");
double (*func)(double) = do_sin ? sin : cos;
printf("/* This file was generated by libavcodec/costablegen */\n");
printf("#define CONFIG_FFT_FLOAT %d\n", !fixed);
printf("#include \"libavcodec/%s\"\n", do_sin ? "rdft.h" : "fft.h");
for (i = 4; i <= BITS; i++) {
int m = 1 << i;
@@ -46,11 +65,12 @@ int main(int argc, char *argv[])
int idx = j > m/4 ? m/2 - j : j;
if (do_sin && j >= m/4)
idx = m/4 - j;
printf(" "FLOATFMT",", func(idx*freq));
printval(func(idx*freq), fixed);
if ((j & 3) == 3)
printf("\n ");
}
printf(" "FLOATFMT"\n};\n", func(do_sin ? -(m/4 - 1)*freq : freq));
printval(func(do_sin ? -(m/4 - 1)*freq : freq), fixed);
printf("\n};\n");
}
return 0;
}

67
libavcodec/fft-internal.h Normal file
View File

@@ -0,0 +1,67 @@
/*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; 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
#include "libavutil/intmath.h"
#include "mathops.h"
#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))
#define BF(x, y, a, b) do { \
x = (a - b) >> 1; \
y = (a + b) >> 1; \
} while (0)
#define CMUL(dre, dim, are, aim, bre, bim) do { \
(dre) = (MUL16(are, bre) - MUL16(aim, bim)) >> 15; \
(dim) = (MUL16(are, bim) + MUL16(aim, bre)) >> 15; \
} while (0)
#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 */

53
libavcodec/fft.c
View File

@@ -30,6 +30,7 @@
#include <string.h>
#include "libavutil/mathematics.h"
#include "fft.h"
#include "fft-internal.h"
/* cos(2*pi*x/n) for 0<=x<=n/4, followed by its reverse */
#if !CONFIG_HARDCODED_TABLES
@@ -47,10 +48,21 @@ COSTABLE(16384);
COSTABLE(32768);
COSTABLE(65536);
#endif
COSTABLE_CONST FFTSample * const ff_cos_tabs[] = {
COSTABLE_CONST FFTSample * const FFT_NAME(ff_cos_tabs)[] = {
NULL, NULL, NULL, NULL,
ff_cos_16, ff_cos_32, ff_cos_64, ff_cos_128, ff_cos_256, ff_cos_512, ff_cos_1024,
ff_cos_2048, ff_cos_4096, ff_cos_8192, ff_cos_16384, ff_cos_32768, ff_cos_65536,
FFT_NAME(ff_cos_16),
FFT_NAME(ff_cos_32),
FFT_NAME(ff_cos_64),
FFT_NAME(ff_cos_128),
FFT_NAME(ff_cos_256),
FFT_NAME(ff_cos_512),
FFT_NAME(ff_cos_1024),
FFT_NAME(ff_cos_2048),
FFT_NAME(ff_cos_4096),
FFT_NAME(ff_cos_8192),
FFT_NAME(ff_cos_16384),
FFT_NAME(ff_cos_32768),
FFT_NAME(ff_cos_65536),
};
static void ff_fft_permute_c(FFTContext *s, FFTComplex *z);
@@ -73,9 +85,9 @@ av_cold void ff_init_ff_cos_tabs(int index)
int i;
int m = 1<<index;
double freq = 2*M_PI/m;
FFTSample *tab = ff_cos_tabs[index];
FFTSample *tab = FFT_NAME(ff_cos_tabs)[index];
for(i=0; i<=m/4; i++)
tab[i] = cos(i*freq);
tab[i] = FIX15(cos(i*freq));
for(i=1; i<m/4; i++)
tab[m/2-i] = tab[i];
#endif
@@ -107,9 +119,11 @@ av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse)
s->mdct_calc = ff_mdct_calc_c;
#endif
#if CONFIG_FFT_FLOAT
if (ARCH_ARM) ff_fft_init_arm(s);
if (HAVE_ALTIVEC) ff_fft_init_altivec(s);
if (HAVE_MMX) ff_fft_init_mmx(s);
#endif
for(j=4; j<=nbits; j++) {
ff_init_ff_cos_tabs(j);
@@ -144,13 +158,6 @@ av_cold void ff_fft_end(FFTContext *s)
av_freep(&s->tmp_buf);
}
#define sqrthalf (float)M_SQRT1_2
#define BF(x,y,a,b) {\
x = a - b;\
y = a + b;\
}
#define BUTTERFLIES(a0,a1,a2,a3) {\
BF(t3, t5, t5, t1);\
BF(a2.re, a0.re, a0.re, t5);\
@@ -174,10 +181,8 @@ av_cold void ff_fft_end(FFTContext *s)
}
#define TRANSFORM(a0,a1,a2,a3,wre,wim) {\
t1 = a2.re * wre + a2.im * wim;\
t2 = a2.im * wre - a2.re * wim;\
t5 = a3.re * wre - a3.im * wim;\
t6 = a3.im * wre + a3.re * wim;\
CMUL(t1, t2, a2.re, a2.im, wre, -wim);\
CMUL(t5, t6, a3.re, a3.im, wre, wim);\
BUTTERFLIES(a0,a1,a2,a3)\
}
@@ -193,7 +198,7 @@ av_cold void ff_fft_end(FFTContext *s)
#define PASS(name)\
static void name(FFTComplex *z, const FFTSample *wre, unsigned int n)\
{\
FFTSample t1, t2, t3, t4, t5, t6;\
FFTDouble t1, t2, t3, t4, t5, t6;\
int o1 = 2*n;\
int o2 = 4*n;\
int o3 = 6*n;\
@@ -222,12 +227,12 @@ static void fft##n(FFTComplex *z)\
fft##n2(z);\
fft##n4(z+n4*2);\
fft##n4(z+n4*3);\
pass(z,ff_cos_##n,n4/2);\
pass(z,FFT_NAME(ff_cos_##n),n4/2);\
}
static void fft4(FFTComplex *z)
{
FFTSample t1, t2, t3, t4, t5, t6, t7, t8;
FFTDouble t1, t2, t3, t4, t5, t6, t7, t8;
BF(t3, t1, z[0].re, z[1].re);
BF(t8, t6, z[3].re, z[2].re);
@@ -241,7 +246,7 @@ static void fft4(FFTComplex *z)
static void fft8(FFTComplex *z)
{
FFTSample t1, t2, t3, t4, t5, t6, t7, t8;
FFTDouble t1, t2, t3, t4, t5, t6, t7, t8;
fft4(z);
@@ -262,7 +267,9 @@ static void fft8(FFTComplex *z)
#if !CONFIG_SMALL
static void fft16(FFTComplex *z)
{
FFTSample t1, t2, t3, t4, t5, t6;
FFTDouble t1, t2, t3, t4, t5, t6;
FFTSample cos_16_1 = FFT_NAME(ff_cos_16)[1];
FFTSample cos_16_3 = FFT_NAME(ff_cos_16)[3];
fft8(z);
fft4(z+8);
@@ -270,8 +277,8 @@ static void fft16(FFTComplex *z)
TRANSFORM_ZERO(z[0],z[4],z[8],z[12]);
TRANSFORM(z[2],z[6],z[10],z[14],sqrthalf,sqrthalf);
TRANSFORM(z[1],z[5],z[9],z[13],ff_cos_16[1],ff_cos_16[3]);
TRANSFORM(z[3],z[7],z[11],z[15],ff_cos_16[3],ff_cos_16[1]);
TRANSFORM(z[1],z[5],z[9],z[13],cos_16_1,cos_16_3);
TRANSFORM(z[3],z[7],z[11],z[15],cos_16_3,cos_16_1);
}
#else
DECL_FFT(16,8,4)

41
libavcodec/fft.h
View File

@@ -22,11 +22,37 @@
#ifndef AVCODEC_FFT_H
#define AVCODEC_FFT_H
#ifndef CONFIG_FFT_FLOAT
#define CONFIG_FFT_FLOAT 1
#endif
#include <stdint.h>
#include "config.h"
#include "libavutil/mem.h"
#if CONFIG_FFT_FLOAT
#include "avfft.h"
#define FFT_NAME(x) x
typedef float FFTDouble;
#else
#define FFT_NAME(x) x ## _fixed
typedef int16_t FFTSample;
typedef int FFTDouble;
typedef struct FFTComplex {
int16_t re, im;
} FFTComplex;
typedef struct FFTContext FFTContext;
#endif /* CONFIG_FFT_FLOAT */
/* FFT computation */
struct FFTContext {
@@ -66,7 +92,7 @@ struct FFTContext {
#endif
#define COSTABLE(size) \
COSTABLE_CONST DECLARE_ALIGNED(16, FFTSample, ff_cos_##size)[size/2]
COSTABLE_CONST DECLARE_ALIGNED(16, FFTSample, FFT_NAME(ff_cos_##size))[size/2]
extern COSTABLE(16);
extern COSTABLE(32);
@@ -81,7 +107,9 @@ extern COSTABLE(8192);
extern COSTABLE(16384);
extern COSTABLE(32768);
extern COSTABLE(65536);
extern COSTABLE_CONST FFTSample* const ff_cos_tabs[17];
extern COSTABLE_CONST FFTSample* const FFT_NAME(ff_cos_tabs)[17];
#define ff_init_ff_cos_tabs FFT_NAME(ff_init_ff_cos_tabs)
/**
* Initialize the cosine table in ff_cos_tabs[index]
@@ -89,6 +117,9 @@ extern COSTABLE_CONST FFTSample* const ff_cos_tabs[17];
*/
void ff_init_ff_cos_tabs(int index);
#define ff_fft_init FFT_NAME(ff_fft_init)
#define ff_fft_end FFT_NAME(ff_fft_end)
/**
* Set up a complex FFT.
* @param nbits log2 of the length of the input array
@@ -102,10 +133,10 @@ void ff_fft_init_arm(FFTContext *s);
void ff_fft_end(FFTContext *s);
#define ff_mdct_init FFT_NAME(ff_mdct_init)
#define ff_mdct_end FFT_NAME(ff_mdct_end)
int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale);
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);
void ff_mdct_end(FFTContext *s);
#endif /* AVCODEC_FFT_H */

20
libavcodec/fft_fixed.c Normal file
View File

@@ -0,0 +1,20 @@
/*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define CONFIG_FFT_FLOAT 0
#include "fft.c"

20
libavcodec/fft_float.c Normal file
View File

@@ -0,0 +1,20 @@
/*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define CONFIG_FFT_FLOAT 1
#include "fft.c"

32
libavcodec/mdct.c
View File

@@ -24,12 +24,19 @@
#include "libavutil/common.h"
#include "libavutil/mathematics.h"
#include "fft.h"
#include "fft-internal.h"
/**
* @file
* MDCT/IMDCT transforms.
*/
#if CONFIG_FFT_FLOAT
# define RSCALE(x) (x)
#else
# define RSCALE(x) ((x) >> 1)
#endif
/**
* init MDCT or IMDCT computation.
*/
@@ -70,8 +77,8 @@ av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
scale = sqrt(fabs(scale));
for(i=0;i<n4;i++) {
alpha = 2 * M_PI * (i + theta) / n;
s->tcos[i*tstep] = -cos(alpha) * scale;
s->tsin[i*tstep] = -sin(alpha) * scale;
s->tcos[i*tstep] = FIX15(-cos(alpha) * scale);
s->tsin[i*tstep] = FIX15(-sin(alpha) * scale);
}
return 0;
fail:
@@ -79,17 +86,6 @@ av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
return -1;
}
/* complex multiplication: p = a * b */
#define CMUL(pre, pim, are, aim, bre, bim) \
{\
FFTSample _are = (are);\
FFTSample _aim = (aim);\
FFTSample _bre = (bre);\
FFTSample _bim = (bim);\
(pre) = _are * _bre - _aim * _bim;\
(pim) = _are * _bim + _aim * _bre;\
}
/**
* Compute the middle half of the inverse MDCT of size N = 2^nbits,
* thus excluding the parts that can be derived by symmetry
@@ -161,7 +157,7 @@ void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input)
void ff_mdct_calc_c(FFTContext *s, FFTSample *out, const FFTSample *input)
{
int i, j, n, n8, n4, n2, n3;
FFTSample re, im;
FFTDouble re, im;
const uint16_t *revtab = s->revtab;
const FFTSample *tcos = s->tcos;
const FFTSample *tsin = s->tsin;
@@ -175,13 +171,13 @@ void ff_mdct_calc_c(FFTContext *s, FFTSample *out, const FFTSample *input)
/* pre rotation */
for(i=0;i<n8;i++) {
re = -input[2*i+n3] - input[n3-1-2*i];
im = -input[n4+2*i] + input[n4-1-2*i];
re = RSCALE(-input[2*i+n3] - input[n3-1-2*i]);
im = RSCALE(-input[n4+2*i] + input[n4-1-2*i]);
j = revtab[i];
CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]);
re = input[2*i] - input[n2-1-2*i];
im = -(input[n2+2*i] + input[n-1-2*i]);
re = RSCALE( input[2*i] - input[n2-1-2*i]);
im = RSCALE(-input[n2+2*i] - input[ n-1-2*i]);
j = revtab[n8 + i];
CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]);
}

20
libavcodec/mdct_fixed.c Normal file
View File

@@ -0,0 +1,20 @@
/*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define CONFIG_FFT_FLOAT 0
#include "mdct.c"

20
libavcodec/mdct_float.c Normal file
View File

@@ -0,0 +1,20 @@
/*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define CONFIG_FFT_FLOAT 1
#include "mdct.c"