FFmpeg  4.3
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/libm.h"
26 #include "libavutil/mathematics.h"
27 #include "fft.h"
28 #include "fft-internal.h"
29 
30 /**
31  * @file
32  * MDCT/IMDCT transforms.
33  */
34 
35 #if FFT_FLOAT
36 # define RSCALE(x, y) ((x) + (y))
37 #else
38 #if FFT_FIXED_32
39 # define RSCALE(x, y) ((int)((x) + (unsigned)(y) + 32) >> 6)
40 #else /* FFT_FIXED_32 */
41 # define RSCALE(x, y) ((int)((x) + (unsigned)(y)) >> 1)
42 #endif /* FFT_FIXED_32 */
43 #endif
44 
45 /**
46  * init MDCT or IMDCT computation.
47  */
48 av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
49 {
50  int n, n4, i;
51  double alpha, theta;
52  int tstep;
53 
54  memset(s, 0, sizeof(*s));
55  n = 1 << nbits;
56  s->mdct_bits = nbits;
57  s->mdct_size = n;
58  n4 = n >> 2;
59  s->mdct_permutation = FF_MDCT_PERM_NONE;
60 
61  if (ff_fft_init(s, s->mdct_bits - 2, inverse) < 0)
62  goto fail;
63 
64  s->tcos = av_malloc_array(n/2, sizeof(FFTSample));
65  if (!s->tcos)
66  goto fail;
67 
68  switch (s->mdct_permutation) {
69  case FF_MDCT_PERM_NONE:
70  s->tsin = s->tcos + n4;
71  tstep = 1;
72  break;
74  s->tsin = s->tcos + 1;
75  tstep = 2;
76  break;
77  default:
78  goto fail;
79  }
80 
81  theta = 1.0 / 8.0 + (scale < 0 ? n4 : 0);
82  scale = sqrt(fabs(scale));
83  for(i=0;i<n4;i++) {
84  alpha = 2 * M_PI * (i + theta) / n;
85 #if FFT_FIXED_32
86  s->tcos[i*tstep] = lrint(-cos(alpha) * 2147483648.0);
87  s->tsin[i*tstep] = lrint(-sin(alpha) * 2147483648.0);
88 #else
89  s->tcos[i*tstep] = FIX15(-cos(alpha) * scale);
90  s->tsin[i*tstep] = FIX15(-sin(alpha) * scale);
91 #endif
92  }
93  return 0;
94  fail:
95  ff_mdct_end(s);
96  return -1;
97 }
98 
99 /**
100  * Compute the middle half of the inverse MDCT of size N = 2^nbits,
101  * thus excluding the parts that can be derived by symmetry
102  * @param output N/2 samples
103  * @param input N/2 samples
104  */
106 {
107  int k, n8, n4, n2, n, j;
108  const uint16_t *revtab = s->revtab;
109  const FFTSample *tcos = s->tcos;
110  const FFTSample *tsin = s->tsin;
111  const FFTSample *in1, *in2;
112  FFTComplex *z = (FFTComplex *)output;
113 
114  n = 1 << s->mdct_bits;
115  n2 = n >> 1;
116  n4 = n >> 2;
117  n8 = n >> 3;
118 
119  /* pre rotation */
120  in1 = input;
121  in2 = input + n2 - 1;
122  for(k = 0; k < n4; k++) {
123  j=revtab[k];
124  CMUL(z[j].re, z[j].im, *in2, *in1, tcos[k], tsin[k]);
125  in1 += 2;
126  in2 -= 2;
127  }
128  s->fft_calc(s, z);
129 
130  /* post rotation + reordering */
131  for(k = 0; k < n8; k++) {
132  FFTSample r0, i0, r1, i1;
133  CMUL(r0, i1, z[n8-k-1].im, z[n8-k-1].re, tsin[n8-k-1], tcos[n8-k-1]);
134  CMUL(r1, i0, z[n8+k ].im, z[n8+k ].re, tsin[n8+k ], tcos[n8+k ]);
135  z[n8-k-1].re = r0;
136  z[n8-k-1].im = i0;
137  z[n8+k ].re = r1;
138  z[n8+k ].im = i1;
139  }
140 }
141 
142 /**
143  * Compute inverse MDCT of size N = 2^nbits
144  * @param output N samples
145  * @param input N/2 samples
146  */
148 {
149  int k;
150  int n = 1 << s->mdct_bits;
151  int n2 = n >> 1;
152  int n4 = n >> 2;
153 
155 
156  for(k = 0; k < n4; k++) {
157  output[k] = -output[n2-k-1];
158  output[n-k-1] = output[n2+k];
159  }
160 }
161 
162 /**
163  * Compute MDCT of size N = 2^nbits
164  * @param input N samples
165  * @param out N/2 samples
166  */
168 {
169  int i, j, n, n8, n4, n2, n3;
170  FFTDouble re, im;
171  const uint16_t *revtab = s->revtab;
172  const FFTSample *tcos = s->tcos;
173  const FFTSample *tsin = s->tsin;
174  FFTComplex *x = (FFTComplex *)out;
175 
176  n = 1 << s->mdct_bits;
177  n2 = n >> 1;
178  n4 = n >> 2;
179  n8 = n >> 3;
180  n3 = 3 * n4;
181 
182  /* pre rotation */
183  for(i=0;i<n8;i++) {
184  re = RSCALE(-input[2*i+n3], - input[n3-1-2*i]);
185  im = RSCALE(-input[n4+2*i], + input[n4-1-2*i]);
186  j = revtab[i];
187  CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]);
188 
189  re = RSCALE( input[2*i] , - input[n2-1-2*i]);
190  im = RSCALE(-input[n2+2*i], - input[ n-1-2*i]);
191  j = revtab[n8 + i];
192  CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]);
193  }
194 
195  s->fft_calc(s, x);
196 
197  /* post rotation */
198  for(i=0;i<n8;i++) {
199  FFTSample r0, i0, r1, i1;
200  CMUL(i1, r0, x[n8-i-1].re, x[n8-i-1].im, -tsin[n8-i-1], -tcos[n8-i-1]);
201  CMUL(i0, r1, x[n8+i ].re, x[n8+i ].im, -tsin[n8+i ], -tcos[n8+i ]);
202  x[n8-i-1].re = r0;
203  x[n8-i-1].im = i0;
204  x[n8+i ].re = r1;
205  x[n8+i ].im = i1;
206  }
207 }
208 
210 {
211  av_freep(&s->tcos);
212  ff_fft_end(s);
213 }
ff_fft_init
#define ff_fft_init
Definition: fft.h:149
libm.h
out
FILE * out
Definition: movenc.c:54
output
filter_frame For filters that do not use the this method is called when a frame is pushed to the filter s input It can be called at any time except in a reentrant way If the input frame is enough to produce output
Definition: filter_design.txt:225
im
float im
Definition: fft.c:82
mathematics.h
fail
#define fail()
Definition: checkasm.h:123
x
FFmpeg Automated Testing Environment ************************************Introduction Using FATE from your FFmpeg source directory Submitting the results to the FFmpeg result aggregation server Uploading new samples to the fate suite FATE makefile targets and variables Makefile targets Makefile variables Examples Introduction **************FATE is an extended regression suite on the client side and a means for results aggregation and presentation on the server side The first part of this document explains how you can use FATE from your FFmpeg source directory to test your ffmpeg binary The second part describes how you can run FATE to submit the results to FFmpeg’s FATE server In any way you can have a look at the publicly viewable FATE results by visiting this as it can be seen if some test on some platform broke with their recent contribution This usually happens on the platforms the developers could not test on The second part of this document describes how you can run FATE to submit your results to FFmpeg’s FATE server If you want to submit your results be sure to check that your combination of OS and compiler is not already listed on the above mentioned website In the third part you can find a comprehensive listing of FATE makefile targets and variables Using FATE from your FFmpeg source directory **********************************************If you want to run FATE on your machine you need to have the samples in place You can get the samples via the build target fate rsync Use this command from the top level source this will cause FATE to fail NOTE To use a custom wrapper to run the pass ‘ target exec’ to ‘configure’ or set the TARGET_EXEC Make variable Submitting the results to the FFmpeg result aggregation server ****************************************************************To submit your results to the server you should run fate through the shell script ‘tests fate sh’ from the FFmpeg sources This script needs to be invoked with a configuration file as its first argument tests fate sh path to fate_config A configuration file template with comments describing the individual configuration variables can be found at ‘doc fate_config sh template’ Create a configuration that suits your based on the configuration template The ‘slot’ configuration variable can be any string that is not yet but it is suggested that you name it adhering to the following pattern ‘ARCH OS COMPILER COMPILER VERSION’ The configuration file itself will be sourced in a shell therefore all shell features may be used This enables you to setup the environment as you need it for your build For your first test runs the ‘fate_recv’ variable should be empty or commented out This will run everything as normal except that it will omit the submission of the results to the server The following files should be present in $workdir as specified in the configuration it may help to try out the ‘ssh’ command with one or more ‘ v’ options You should get detailed output concerning your SSH configuration and the authentication process The only thing left is to automate the execution of the fate sh script and the synchronisation of the samples directory Uploading new samples to the fate suite *****************************************If you need a sample uploaded send a mail to samples request This is for developers who have an account on the fate suite server If you upload new please make sure they are as small as space on each network bandwidth and so on benefit from smaller test cases Also keep in mind older checkouts use existing sample that means in practice generally do not remove or overwrite files as it likely would break older checkouts or releases Also all needed samples for a commit should be ideally before the push If you need an account for frequently uploading samples or you wish to help others by doing that send a mail to ffmpeg devel rsync vauL Duo x
Definition: fate.txt:150
lrint
#define lrint
Definition: tablegen.h:53
av_cold
#define av_cold
Definition: attributes.h:90
s
#define s(width, name)
Definition: cbs_vp9.c:257
ff_fft_end
#define ff_fft_end
Definition: fft.h:150
ff_mdct_end
av_cold void ff_mdct_end(FFTContext *s)
Definition: mdct_template.c:209
ff_mdct_init
av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
init MDCT or IMDCT computation.
Definition: mdct_template.c:48
RSCALE
#define RSCALE(x, y)
Definition: mdct_template.c:36
ff_mdct_calc_c
void ff_mdct_calc_c(FFTContext *s, FFTSample *out, const FFTSample *input)
Compute MDCT of size N = 2^nbits.
Definition: mdct_template.c:167
fft-internal.h
FFTSample
float FFTSample
Definition: avfft.h:35
FFTComplex::im
FFTSample im
Definition: avfft.h:38
FFTDouble
float FFTDouble
Definition: fft.h:43
FFTComplex::re
FFTSample re
Definition: avfft.h:38
input
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some input
Definition: filter_design.txt:172
M_PI
#define M_PI
Definition: mathematics.h:52
FFTContext
Definition: fft.h:88
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
FF_MDCT_PERM_INTERLEAVE
@ FF_MDCT_PERM_INTERLEAVE
Definition: fft.h:85
av_malloc_array
#define av_malloc_array(a, b)
Definition: tableprint_vlc.h:32
common.h
ff_imdct_calc_c
void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input)
Compute inverse MDCT of size N = 2^nbits.
Definition: mdct_template.c:147
fft.h
ff_imdct_half_c
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:105
alpha
static const int16_t alpha[]
Definition: ilbcdata.h:55
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
FF_MDCT_PERM_NONE
@ FF_MDCT_PERM_NONE
Definition: fft.h:84
inverse
static uint32_t inverse(uint32_t v)
find multiplicative inverse modulo 2 ^ 32
Definition: asfcrypt.c:35
FIX15
#define FIX15(a)
Definition: fft-internal.h:62
CMUL
#define CMUL(dre, dim, are, aim, bre, bim)
Definition: fft-internal.h:76
FFTComplex
Definition: avfft.h:37
re
float re
Definition: fft.c:82