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mdct_template.c
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1 /*
2  * MDCT/IMDCT transforms
3  * Copyright (c) 2002 Fabrice Bellard
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 
22 #include <stdlib.h>
23 #include <string.h>
24 #include "libavutil/common.h"
25 #include "libavutil/mathematics.h"
26 #include "fft.h"
27 #include "fft-internal.h"
28 
29 /**
30  * @file
31  * MDCT/IMDCT transforms.
32  */
33 
34 #if FFT_FLOAT
35 # define RSCALE(x) (x)
36 #else
37 #if FFT_FIXED_32
38 # define RSCALE(x) (((x) + 32) >> 6)
39 #else /* FFT_FIXED_32 */
40 # define RSCALE(x) ((x) >> 1)
41 #endif /* FFT_FIXED_32 */
42 #endif
43 
44 /**
45  * init MDCT or IMDCT computation.
46  */
47 av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
48 {
49  int n, n4, i;
50  double alpha, theta;
51  int tstep;
52 
53  memset(s, 0, sizeof(*s));
54  n = 1 << nbits;
55  s->mdct_bits = nbits;
56  s->mdct_size = n;
57  n4 = n >> 2;
59 
60  if (ff_fft_init(s, s->mdct_bits - 2, inverse) < 0)
61  goto fail;
62 
63  s->tcos = av_malloc_array(n/2, sizeof(FFTSample));
64  if (!s->tcos)
65  goto fail;
66 
67  switch (s->mdct_permutation) {
68  case FF_MDCT_PERM_NONE:
69  s->tsin = s->tcos + n4;
70  tstep = 1;
71  break;
73  s->tsin = s->tcos + 1;
74  tstep = 2;
75  break;
76  default:
77  goto fail;
78  }
79 
80  theta = 1.0 / 8.0 + (scale < 0 ? n4 : 0);
81  scale = sqrt(fabs(scale));
82  for(i=0;i<n4;i++) {
83  alpha = 2 * M_PI * (i + theta) / n;
84  s->tcos[i*tstep] = FIX15(-cos(alpha) * scale);
85  s->tsin[i*tstep] = FIX15(-sin(alpha) * scale);
86  }
87  return 0;
88  fail:
89  ff_mdct_end(s);
90  return -1;
91 }
92 
93 /**
94  * Compute the middle half of the inverse MDCT of size N = 2^nbits,
95  * thus excluding the parts that can be derived by symmetry
96  * @param output N/2 samples
97  * @param input N/2 samples
98  */
99 void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input)
100 {
101  int k, n8, n4, n2, n, j;
102  const uint16_t *revtab = s->revtab;
103  const FFTSample *tcos = s->tcos;
104  const FFTSample *tsin = s->tsin;
105  const FFTSample *in1, *in2;
106  FFTComplex *z = (FFTComplex *)output;
107 
108  n = 1 << s->mdct_bits;
109  n2 = n >> 1;
110  n4 = n >> 2;
111  n8 = n >> 3;
112 
113  /* pre rotation */
114  in1 = input;
115  in2 = input + n2 - 1;
116  for(k = 0; k < n4; k++) {
117  j=revtab[k];
118  CMUL(z[j].re, z[j].im, *in2, *in1, tcos[k], tsin[k]);
119  in1 += 2;
120  in2 -= 2;
121  }
122  s->fft_calc(s, z);
123 
124  /* post rotation + reordering */
125  for(k = 0; k < n8; k++) {
126  FFTSample r0, i0, r1, i1;
127  CMUL(r0, i1, z[n8-k-1].im, z[n8-k-1].re, tsin[n8-k-1], tcos[n8-k-1]);
128  CMUL(r1, i0, z[n8+k ].im, z[n8+k ].re, tsin[n8+k ], tcos[n8+k ]);
129  z[n8-k-1].re = r0;
130  z[n8-k-1].im = i0;
131  z[n8+k ].re = r1;
132  z[n8+k ].im = i1;
133  }
134 }
135 
136 /**
137  * Compute inverse MDCT of size N = 2^nbits
138  * @param output N samples
139  * @param input N/2 samples
140  */
141 void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input)
142 {
143  int k;
144  int n = 1 << s->mdct_bits;
145  int n2 = n >> 1;
146  int n4 = n >> 2;
147 
148  ff_imdct_half_c(s, output+n4, input);
149 
150  for(k = 0; k < n4; k++) {
151  output[k] = -output[n2-k-1];
152  output[n-k-1] = output[n2+k];
153  }
154 }
155 
156 /**
157  * Compute MDCT of size N = 2^nbits
158  * @param input N samples
159  * @param out N/2 samples
160  */
162 {
163  int i, j, n, n8, n4, n2, n3;
164  FFTDouble re, im;
165  const uint16_t *revtab = s->revtab;
166  const FFTSample *tcos = s->tcos;
167  const FFTSample *tsin = s->tsin;
168  FFTComplex *x = (FFTComplex *)out;
169 
170  n = 1 << s->mdct_bits;
171  n2 = n >> 1;
172  n4 = n >> 2;
173  n8 = n >> 3;
174  n3 = 3 * n4;
175 
176  /* pre rotation */
177  for(i=0;i<n8;i++) {
178  re = RSCALE(-input[2*i+n3] - input[n3-1-2*i]);
179  im = RSCALE(-input[n4+2*i] + input[n4-1-2*i]);
180  j = revtab[i];
181  CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]);
182 
183  re = RSCALE( input[2*i] - input[n2-1-2*i]);
184  im = RSCALE(-input[n2+2*i] - input[ n-1-2*i]);
185  j = revtab[n8 + i];
186  CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]);
187  }
188 
189  s->fft_calc(s, x);
190 
191  /* post rotation */
192  for(i=0;i<n8;i++) {
193  FFTSample r0, i0, r1, i1;
194  CMUL(i1, r0, x[n8-i-1].re, x[n8-i-1].im, -tsin[n8-i-1], -tcos[n8-i-1]);
195  CMUL(i0, r1, x[n8+i ].re, x[n8+i ].im, -tsin[n8+i ], -tcos[n8+i ]);
196  x[n8-i-1].re = r0;
197  x[n8-i-1].im = i0;
198  x[n8+i ].re = r1;
199  x[n8+i ].im = i1;
200  }
201 }
202 
204 {
205  av_freep(&s->tcos);
206  ff_fft_end(s);
207 }
float FFTDouble
Definition: fft.h:43
const char * s
Definition: avisynth_c.h:631
av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
init MDCT or IMDCT computation.
Definition: mdct_template.c:47
FFTSample re
Definition: avfft.h:38
void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input)
Compute the middle half of the inverse MDCT of size N = 2^nbits, thus excluding the parts that can be...
Definition: mdct_template.c:99
#define av_cold
Definition: attributes.h:74
#define CMUL(dre, dim, are, aim, bre, bim)
Definition: fft-internal.h:76
void ff_mdct_calc_c(FFTContext *s, FFTSample *out, const FFTSample *input)
Compute MDCT of size N = 2^nbits.
static double alpha(void *priv, double x, double y)
Definition: vf_geq.c:98
#define FIX15(a)
Definition: fft-internal.h:62
av_cold void ff_mdct_end(FFTContext *s)
float FFTSample
Definition: avfft.h:35
Definition: fft.h:88
FFTSample * tsin
Definition: fft.h:97
#define ff_fft_init
Definition: fft.h:147
int n
Definition: avisynth_c.h:547
float im
Definition: fft-test.c:73
#define RSCALE(x)
Definition: mdct_template.c:35
int mdct_bits
Definition: fft.h:94
FFTSample im
Definition: avfft.h:38
common internal and external API header
#define ff_fft_end
Definition: fft.h:148
FFTSample * tcos
Definition: fft.h:96
void(* fft_calc)(struct FFTContext *s, FFTComplex *z)
Do a complex FFT with the parameters defined in ff_fft_init().
Definition: fft.h:106
float re
Definition: fft-test.c:73
uint8_t pi<< 24) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_U8, uint8_t,(*(constuint8_t *) pi-0x80)*(1.0f/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_U8, uint8_t,(*(constuint8_t *) pi-0x80)*(1.0/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S16, int16_t,(*(constint16_t *) pi >>8)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S16, int16_t,*(constint16_t *) pi *(1.0f/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S16, int16_t,*(constint16_t *) pi *(1.0/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S32, int32_t,(*(constint32_t *) pi >>24)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S32, int32_t,*(constint32_t *) pi *(1.0f/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S32, int32_t,*(constint32_t *) pi *(1.0/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_FLT, float, av_clip_uint8(lrintf(*(constfloat *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_FLT, float, av_clip_int16(lrintf(*(constfloat *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_FLT, float, av_clipl_int32(llrintf(*(constfloat *) pi *(1U<< 31)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_DBL, double, av_clip_uint8(lrint(*(constdouble *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_DBL, double, av_clip_int16(lrint(*(constdouble *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_DBL, double, av_clipl_int32(llrint(*(constdouble *) pi *(1U<< 31))))#defineSET_CONV_FUNC_GROUP(ofmt, ifmt) staticvoidset_generic_function(AudioConvert *ac){}voidff_audio_convert_free(AudioConvert **ac){if(!*ac) return;ff_dither_free(&(*ac) ->dc);av_freep(ac);}AudioConvert *ff_audio_convert_alloc(AVAudioResampleContext *avr, enumAVSampleFormatout_fmt, enumAVSampleFormatin_fmt, intchannels, intsample_rate, intapply_map){AudioConvert *ac;intin_planar, out_planar;ac=av_mallocz(sizeof(*ac));if(!ac) returnNULL;ac->avr=avr;ac->out_fmt=out_fmt;ac->in_fmt=in_fmt;ac->channels=channels;ac->apply_map=apply_map;if(avr->dither_method!=AV_RESAMPLE_DITHER_NONE &&av_get_packed_sample_fmt(out_fmt)==AV_SAMPLE_FMT_S16 &&av_get_bytes_per_sample(in_fmt)>2){ac->dc=ff_dither_alloc(avr, out_fmt, in_fmt, channels, sample_rate, apply_map);if(!ac->dc){av_free(ac);returnNULL;}returnac;}in_planar=ff_sample_fmt_is_planar(in_fmt, channels);out_planar=ff_sample_fmt_is_planar(out_fmt, channels);if(in_planar==out_planar){ac->func_type=CONV_FUNC_TYPE_FLAT;ac->planes=in_planar?ac->channels:1;}elseif(in_planar) ac->func_type=CONV_FUNC_TYPE_INTERLEAVE;elseac->func_type=CONV_FUNC_TYPE_DEINTERLEAVE;set_generic_function(ac);if(ARCH_AARCH64) ff_audio_convert_init_aarch64(ac);if(ARCH_ARM) ff_audio_convert_init_arm(ac);if(ARCH_X86) ff_audio_convert_init_x86(ac);returnac;}intff_audio_convert(AudioConvert *ac, AudioData *out, AudioData *in){intuse_generic=1;intlen=in->nb_samples;intp;if(ac->dc){av_log(ac->avr, AV_LOG_TRACE,"%dsamples-audio_convert:%sto%s(dithered)\n", len, av_get_sample_fmt_name(ac->in_fmt), av_get_sample_fmt_name(ac->out_fmt));returnff_convert_dither(ac-> out
#define av_freep(p)
uint16_t * revtab
Definition: fft.h:91
#define M_PI
Definition: mathematics.h:46
static uint32_t inverse(uint32_t v)
find multiplicative inverse modulo 2 ^ 32
Definition: asfcrypt.c:35
#define av_malloc_array(a, b)
int mdct_size
Definition: fft.h:93
enum mdct_permutation_type mdct_permutation
Definition: fft.h:112
void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input)
Compute inverse MDCT of size N = 2^nbits.