diff options
Diffstat (limited to 'lib/rbcodec/codecs/libwmavoice/rdft.c')
-rw-r--r-- | lib/rbcodec/codecs/libwmavoice/rdft.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libwmavoice/rdft.c b/lib/rbcodec/codecs/libwmavoice/rdft.c new file mode 100644 index 0000000000..bc44f5aef2 --- /dev/null +++ b/lib/rbcodec/codecs/libwmavoice/rdft.c | |||
@@ -0,0 +1,133 @@ | |||
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 <stdlib.h> | ||
22 | #include <math.h> | ||
23 | #include "libavutil/mathematics.h" | ||
24 | #include "fft.h" | ||
25 | |||
26 | /** | ||
27 | * @file | ||
28 | * (Inverse) Real Discrete Fourier Transforms. | ||
29 | */ | ||
30 | |||
31 | /* sin(2*pi*x/n) for 0<=x<n/4, followed by n/2<=x<3n/4 */ | ||
32 | #if !CONFIG_HARDCODED_TABLES | ||
33 | SINTABLE(16); | ||
34 | SINTABLE(32); | ||
35 | SINTABLE(64); | ||
36 | SINTABLE(128); | ||
37 | SINTABLE(256); | ||
38 | SINTABLE(512); | ||
39 | SINTABLE(1024); | ||
40 | SINTABLE(2048); | ||
41 | SINTABLE(4096); | ||
42 | SINTABLE(8192); | ||
43 | SINTABLE(16384); | ||
44 | SINTABLE(32768); | ||
45 | SINTABLE(65536); | ||
46 | #endif | ||
47 | SINTABLE_CONST FFTSample * const ff_sin_tabs[] = { | ||
48 | NULL, NULL, NULL, NULL, | ||
49 | ff_sin_16, ff_sin_32, ff_sin_64, ff_sin_128, ff_sin_256, ff_sin_512, ff_sin_1024, | ||
50 | ff_sin_2048, ff_sin_4096, ff_sin_8192, ff_sin_16384, ff_sin_32768, ff_sin_65536, | ||
51 | }; | ||
52 | |||
53 | /** Map one real FFT into two parallel real even and odd FFTs. Then interleave | ||
54 | * the two real FFTs into one complex FFT. Unmangle the results. | ||
55 | * ref: http://www.engineeringproductivitytools.com/stuff/T0001/PT10.HTM | ||
56 | */ | ||
57 | static void ff_rdft_calc_c(RDFTContext* s, FFTSample* data) | ||
58 | { | ||
59 | int i, i1, i2; | ||
60 | FFTComplex ev, od; | ||
61 | const int n = 1 << s->nbits; | ||
62 | const float k1 = 0.5; | ||
63 | const float k2 = 0.5 - s->inverse; | ||
64 | const FFTSample *tcos = s->tcos; | ||
65 | const FFTSample *tsin = s->tsin; | ||
66 | |||
67 | if (!s->inverse) { | ||
68 | ff_fft_permute(&s->fft, (FFTComplex*)data); | ||
69 | ff_fft_calc(&s->fft, (FFTComplex*)data); | ||
70 | } | ||
71 | /* i=0 is a special case because of packing, the DC term is real, so we | ||
72 | are going to throw the N/2 term (also real) in with it. */ | ||
73 | ev.re = data[0]; | ||
74 | data[0] = ev.re+data[1]; | ||
75 | data[1] = ev.re-data[1]; | ||
76 | for (i = 1; i < (n>>2); i++) { | ||
77 | i1 = 2*i; | ||
78 | i2 = n-i1; | ||
79 | /* Separate even and odd FFTs */ | ||
80 | ev.re = k1*(data[i1 ]+data[i2 ]); | ||
81 | od.im = -k2*(data[i1 ]-data[i2 ]); | ||
82 | ev.im = k1*(data[i1+1]-data[i2+1]); | ||
83 | od.re = k2*(data[i1+1]+data[i2+1]); | ||
84 | /* Apply twiddle factors to the odd FFT and add to the even FFT */ | ||
85 | data[i1 ] = ev.re + od.re*tcos[i] - od.im*tsin[i]; | ||
86 | data[i1+1] = ev.im + od.im*tcos[i] + od.re*tsin[i]; | ||
87 | data[i2 ] = ev.re - od.re*tcos[i] + od.im*tsin[i]; | ||
88 | data[i2+1] = -ev.im + od.im*tcos[i] + od.re*tsin[i]; | ||
89 | } | ||
90 | data[2*i+1]=s->sign_convention*data[2*i+1]; | ||
91 | if (s->inverse) { | ||
92 | data[0] *= k1; | ||
93 | data[1] *= k1; | ||
94 | ff_fft_permute(&s->fft, (FFTComplex*)data); | ||
95 | ff_fft_calc(&s->fft, (FFTComplex*)data); | ||
96 | } | ||
97 | } | ||
98 | |||
99 | av_cold int ff_rdft_init(RDFTContext *s, int nbits, enum RDFTransformType trans) | ||
100 | { | ||
101 | int n = 1 << nbits; | ||
102 | int i; | ||
103 | const double theta = (trans == DFT_R2C || trans == DFT_C2R ? -1 : 1)*2*M_PI/n; | ||
104 | |||
105 | s->nbits = nbits; | ||
106 | s->inverse = trans == IDFT_C2R || trans == DFT_C2R; | ||
107 | s->sign_convention = trans == IDFT_R2C || trans == DFT_C2R ? 1 : -1; | ||
108 | |||
109 | if (nbits < 4 || nbits > 16) | ||
110 | return -1; | ||
111 | |||
112 | if (ff_fft_init(&s->fft, nbits-1, trans == IDFT_C2R || trans == IDFT_R2C) < 0) | ||
113 | return -1; | ||
114 | |||
115 | ff_init_ff_cos_tabs(nbits); | ||
116 | s->tcos = ff_cos_tabs[nbits]; | ||
117 | s->tsin = ff_sin_tabs[nbits]+(trans == DFT_R2C || trans == DFT_C2R)*(n>>2); | ||
118 | #if !CONFIG_HARDCODED_TABLES | ||
119 | for (i = 0; i < (n>>2); i++) { | ||
120 | s->tsin[i] = sin(i*theta); | ||
121 | } | ||
122 | #endif | ||
123 | s->rdft_calc = ff_rdft_calc_c; | ||
124 | |||
125 | //if (ARCH_ARM) ff_rdft_init_arm(s); | ||
126 | |||
127 | return 0; | ||
128 | } | ||
129 | |||
130 | av_cold void ff_rdft_end(RDFTContext *s) | ||
131 | { | ||
132 | ff_fft_end(&s->fft); | ||
133 | } | ||