Revision 68602540

View differences:

configure
102 102
  echo "  --disable-fft            disable FFT code"
103 103
  echo "  --disable-golomb         disable Golomb code"
104 104
  echo "  --disable-mdct           disable MDCT code"
105
  echo "  --disable-rdft           disable RDFT code"
105 106
  echo "  --enable-hardcoded-tables use hardcoded tables instead of runtime generation"
106 107
  echo "  --enable-memalign-hack   emulate memalign, interferes with memory debuggers"
107 108
  echo "  --enable-beos-netserver  enable BeOS netserver"
......
781 782
    nonfree
782 783
    postproc
783 784
    powerpc_perf
785
    rdft
784 786
    shared
785 787
    small
786 788
    static
libavcodec/Makefile
29 29
OBJS-$(CONFIG_FFT)                     += fft.o
30 30
OBJS-$(CONFIG_GOLOMB)                  += golomb.o
31 31
OBJS-$(CONFIG_MDCT)                    += mdct.o
32
OBJS-$(CONFIG_RDFT)                    += rdft.o
32 33
OBJS-$(CONFIG_OLDSCALER)               += imgresample.o
33 34

  
34 35
# decoders/encoders
libavcodec/dsputil.h
674 674
    void (*imdct_half)(struct MDCTContext *s, FFTSample *output, const FFTSample *input);
675 675
} FFTContext;
676 676

  
677
extern FFTSample* ff_cos_tabs[13];
678

  
677 679
/**
678 680
 * Sets up a complex FFT.
679 681
 * @param nbits           log2 of the length of the input array
......
759 761
void ff_mdct_calc(MDCTContext *s, FFTSample *out, const FFTSample *input);
760 762
void ff_mdct_end(MDCTContext *s);
761 763

  
764
/* Real Discrete Fourier Transform */
765

  
766
enum RDFTransformType {
767
    RDFT,
768
    IRDFT,
769
    RIDFT,
770
    IRIDFT,
771
};
772

  
773
typedef struct {
774
    int nbits;
775
    int inverse;
776
    int sign_convention;
777

  
778
    /* pre/post rotation tables */
779
    FFTSample *tcos;
780
    FFTSample *tsin;
781
    FFTContext fft;
782
} RDFTContext;
783

  
784
/**
785
 * Sets up a real FFT.
786
 * @param nbits           log2 of the length of the input array
787
 * @param trans           the type of transform
788
 */
789
int ff_rdft_init(RDFTContext *s, int nbits, enum RDFTransformType trans);
790
void ff_rdft_calc(RDFTContext *s, FFTSample *data);
791
void ff_rdft_end(RDFTContext *s);
792

  
762 793
#define WRAPPER8_16(name8, name16)\
763 794
static int name16(void /*MpegEncContext*/ *s, uint8_t *dst, uint8_t *src, int stride, int h){\
764 795
    return name8(s, dst           , src           , stride, h)\
libavcodec/fft.c
42 42
DECLARE_ALIGNED_16(FFTSample, ff_cos_16384[8192]);
43 43
DECLARE_ALIGNED_16(FFTSample, ff_cos_32768[16384]);
44 44
DECLARE_ALIGNED_16(FFTSample, ff_cos_65536[32768]);
45
static FFTSample *ff_cos_tabs[] = {
45
FFTSample *ff_cos_tabs[] = {
46 46
    ff_cos_16, ff_cos_32, ff_cos_64, ff_cos_128, ff_cos_256, ff_cos_512, ff_cos_1024,
47 47
    ff_cos_2048, ff_cos_4096, ff_cos_8192, ff_cos_16384, ff_cos_32768, ff_cos_65536,
48 48
};
libavcodec/rdft.c
1
/*
2
 * (I)RDFT transforms
3
 * Copyright (c) 2009 Alex Converse <alex dot converse at gmail dot com>
4
 *
5
 * This file is part of FFmpeg.
6
 *
7
 * FFmpeg is free software; you can redistribute it and/or
8
 * modify it under the terms of the GNU Lesser General Public
9
 * License as published by the Free Software Foundation; either
10
 * version 2.1 of the License, or (at your option) any later version.
11
 *
12
 * FFmpeg is distributed in the hope that it will be useful,
13
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15
 * Lesser General Public License for more details.
16
 *
17
 * You should have received a copy of the GNU Lesser General Public
18
 * License along with FFmpeg; if not, write to the Free Software
19
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
 */
21
#include <math.h>
22
#include "dsputil.h"
23

  
24
/**
25
 * @file rdft.c
26
 * (Inverse) Real Discrete Fourier Transforms.
27
 */
28

  
29
/* sin(2*pi*x/n) for 0<=x<n/4, followed by n/2<=x<3n/4 */
30
DECLARE_ALIGNED_16(FFTSample, ff_sin_16[8]);
31
DECLARE_ALIGNED_16(FFTSample, ff_sin_32[16]);
32
DECLARE_ALIGNED_16(FFTSample, ff_sin_64[32]);
33
DECLARE_ALIGNED_16(FFTSample, ff_sin_128[64]);
34
DECLARE_ALIGNED_16(FFTSample, ff_sin_256[128]);
35
DECLARE_ALIGNED_16(FFTSample, ff_sin_512[256]);
36
DECLARE_ALIGNED_16(FFTSample, ff_sin_1024[512]);
37
DECLARE_ALIGNED_16(FFTSample, ff_sin_2048[1024]);
38
DECLARE_ALIGNED_16(FFTSample, ff_sin_4096[2048]);
39
DECLARE_ALIGNED_16(FFTSample, ff_sin_8192[4096]);
40
DECLARE_ALIGNED_16(FFTSample, ff_sin_16384[8192]);
41
DECLARE_ALIGNED_16(FFTSample, ff_sin_32768[16384]);
42
DECLARE_ALIGNED_16(FFTSample, ff_sin_65536[32768]);
43
FFTSample *ff_sin_tabs[] = {
44
    ff_sin_16, ff_sin_32, ff_sin_64, ff_sin_128, ff_sin_256, ff_sin_512, ff_sin_1024,
45
    ff_sin_2048, ff_sin_4096, ff_sin_8192, ff_sin_16384, ff_sin_32768, ff_sin_65536,
46
};
47

  
48
av_cold int ff_rdft_init(RDFTContext *s, int nbits, enum RDFTransformType trans)
49
{
50
    int n = 1 << nbits;
51
    int i;
52
    const double theta = (trans == RDFT || trans == IRIDFT ? -1 : 1)*2*M_PI/n;
53

  
54
    s->nbits           = nbits;
55
    s->inverse         = trans == IRDFT || trans == IRIDFT;
56
    s->sign_convention = trans == RIDFT || trans == IRIDFT ? 1 : -1;
57

  
58
    if (nbits < 4 || nbits > 16)
59
        return -1;
60

  
61
    if (ff_fft_init(&s->fft, nbits-1, trans == IRDFT || trans == RIDFT) < 0)
62
        return -1;
63

  
64
    s->tcos = ff_cos_tabs[nbits-4];
65
    s->tsin = ff_sin_tabs[nbits-4]+(trans == RDFT || trans == IRIDFT)*(n>>2);
66
    for (i = 0; i < (n>>2); i++) {
67
        s->tcos[i] = cos(i*theta);
68
        s->tsin[i] = sin(i*theta);
69
    }
70
    return 0;
71
}
72

  
73
/** Map one real FFT into two parallel real even and odd FFTs. Then interleave
74
 * the two real FFTs into one complex FFT. Unmangle the results.
75
 * ref: http://www.engineeringproductivitytools.com/stuff/T0001/PT10.HTM
76
 */
77
void ff_rdft_calc_c(RDFTContext* s, FFTSample* data)
78
{
79
    int i, i1, i2;
80
    FFTComplex ev, od;
81
    const int n = 1 << s->nbits;
82
    const float k1 = 0.5;
83
    const float k2 = 0.5 - s->inverse;
84
    const FFTSample *tcos = s->tcos;
85
    const FFTSample *tsin = s->tsin;
86

  
87
    if (!s->inverse) {
88
        ff_fft_permute(&s->fft, (FFTComplex*)data);
89
        ff_fft_calc(&s->fft, (FFTComplex*)data);
90
    }
91
    /* i=0 is a special case because of packing, the DC term is real, so we
92
       are going to throw the N/2 term (also real) in with it. */
93
    ev.re = data[0];
94
    data[0] = ev.re+data[1];
95
    data[1] = ev.re-data[1];
96
    for (i = 1; i < (n>>2); i++) {
97
        i1 = 2*i;
98
        i2 = n-i1;
99
        /* Separate even and odd FFTs */
100
        ev.re =  k1*(data[i1  ]+data[i2  ]);
101
        od.im = -k2*(data[i1  ]-data[i2  ]);
102
        ev.im =  k1*(data[i1+1]-data[i2+1]);
103
        od.re =  k2*(data[i1+1]+data[i2+1]);
104
        /* Apply twiddle factors to the odd FFT and add to the even FFT */
105
        data[i1  ] =  ev.re + od.re*tcos[i] - od.im*tsin[i];
106
        data[i1+1] =  ev.im + od.im*tcos[i] + od.re*tsin[i];
107
        data[i2  ] =  ev.re - od.re*tcos[i] + od.im*tsin[i];
108
        data[i2+1] = -ev.im + od.im*tcos[i] + od.re*tsin[i];
109
    }
110
    data[2*i+1]=s->sign_convention*data[2*i+1];
111
    if (s->inverse) {
112
        data[0] *= k1;
113
        data[1] *= k1;
114
        ff_fft_permute(&s->fft, (FFTComplex*)data);
115
        ff_fft_calc(&s->fft, (FFTComplex*)data);
116
    }
117
}
118

  
119
void ff_rdft_calc(RDFTContext *s, FFTSample *data)
120
{
121
    ff_rdft_calc_c(s, data);
122
}
123

  
124
av_cold void ff_rdft_end(RDFTContext *s)
125
{
126
    ff_fft_end(&s->fft);
127
}

Also available in: Unified diff