FFmpeg  4.3
lfg.c
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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * FFmpeg is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with FFmpeg; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 #include "libavutil/log.h"
20 #include "libavutil/timer.h"
21 #include "libavutil/lfg.h"
22 
23 static const double Z_TABLE[31][10] = {
24  {0.5000, 0.5040, 0.5080, 0.5120, 0.5160, 0.5199, 0.5239, 0.5279, 0.5319, 0.5359},
25  {0.5398, 0.5438, 0.5478, 0.5517, 0.5557, 0.5596, 0.5636, 0.5675, 0.5714, 0.5753},
26  {0.5793, 0.5832, 0.5871, 0.5910, 0.5948, 0.5987, 0.6026, 0.6064, 0.6103, 0.6141},
27  {0.6179, 0.6217, 0.6255, 0.6293, 0.6331, 0.6368, 0.6406, 0.6443, 0.6480, 0.6517},
28  {0.6554, 0.6591, 0.6628, 0.6664, 0.6700, 0.6736, 0.6772, 0.6808, 0.6844, 0.6879},
29  {0.6915, 0.6950, 0.6985, 0.7019, 0.7054, 0.7088, 0.7123, 0.7157, 0.7190, 0.7224},
30  {0.7257, 0.7291, 0.7324, 0.7357, 0.7389, 0.7422, 0.7454, 0.7486, 0.7517, 0.7549},
31  {0.7580, 0.7611, 0.7642, 0.7673, 0.7704, 0.7734, 0.7764, 0.7794, 0.7823, 0.7852},
32  {0.7881, 0.7910, 0.7939, 0.7967, 0.7995, 0.8023, 0.8051, 0.8078, 0.8106, 0.8133},
33  {0.8159, 0.8186, 0.8212, 0.8238, 0.8264, 0.8289, 0.8315, 0.8340, 0.8365, 0.8389},
34  {0.8413, 0.8438, 0.8461, 0.8485, 0.8508, 0.8531, 0.8554, 0.8577, 0.8599, 0.8621},
35  {0.8643, 0.8665, 0.8686, 0.8708, 0.8729, 0.8749, 0.8770, 0.8790, 0.8810, 0.8830},
36  {0.8849, 0.8869, 0.8888, 0.8907, 0.8925, 0.8944, 0.8962, 0.8980, 0.8997, 0.9015},
37  {0.9032, 0.9049, 0.9066, 0.9082, 0.9099, 0.9115, 0.9131, 0.9147, 0.9162, 0.9177},
38  {0.9192, 0.9207, 0.9222, 0.9236, 0.9251, 0.9265, 0.9279, 0.9292, 0.9306, 0.9319},
39  {0.9332, 0.9345, 0.9357, 0.9370, 0.9382, 0.9394, 0.9406, 0.9418, 0.9429, 0.9441},
40  {0.9452, 0.9463, 0.9474, 0.9484, 0.9495, 0.9505, 0.9515, 0.9525, 0.9535, 0.9545},
41  {0.9554, 0.9564, 0.9573, 0.9582, 0.9591, 0.9599, 0.9608, 0.9616, 0.9625, 0.9633},
42  {0.9641, 0.9649, 0.9656, 0.9664, 0.9671, 0.9678, 0.9686, 0.9693, 0.9699, 0.9706},
43  {0.9713, 0.9719, 0.9726, 0.9732, 0.9738, 0.9744, 0.9750, 0.9756, 0.9761, 0.9767},
44  {0.9772, 0.9778, 0.9783, 0.9788, 0.9793, 0.9798, 0.9803, 0.9808, 0.9812, 0.9817},
45  {0.9821, 0.9826, 0.9830, 0.9834, 0.9838, 0.9842, 0.9846, 0.9850, 0.9854, 0.9857},
46  {0.9861, 0.9864, 0.9868, 0.9871, 0.9875, 0.9878, 0.9881, 0.9884, 0.9887, 0.9890},
47  {0.9893, 0.9896, 0.9898, 0.9901, 0.9904, 0.9906, 0.9909, 0.9911, 0.9913, 0.9916},
48  {0.9918, 0.9920, 0.9922, 0.9925, 0.9927, 0.9929, 0.9931, 0.9932, 0.9934, 0.9936},
49  {0.9938, 0.9940, 0.9941, 0.9943, 0.9945, 0.9946, 0.9948, 0.9949, 0.9951, 0.9952},
50  {0.9953, 0.9955, 0.9956, 0.9957, 0.9959, 0.9960, 0.9961, 0.9962, 0.9963, 0.9964},
51  {0.9965, 0.9966, 0.9967, 0.9968, 0.9969, 0.9970, 0.9971, 0.9972, 0.9973, 0.9974},
52  {0.9974, 0.9975, 0.9976, 0.9977, 0.9977, 0.9978, 0.9979, 0.9979, 0.9980, 0.9981},
53  {0.9981, 0.9982, 0.9982, 0.9983, 0.9984, 0.9984, 0.9985, 0.9985, 0.9986, 0.9986},
54  {0.9987, 0.9987, 0.9987, 0.9988, 0.9988, 0.9989, 0.9989, 0.9989, 0.9990, 0.9990} };
55 
56 // Inverse cumulative distribution function
57 static double inv_cdf(double u)
58 {
59  const double a[4] = { 2.50662823884,
60  -18.61500062529,
61  41.39119773534,
62  -25.44106049637};
63 
64  const double b[4] = {-8.47351093090,
65  23.08336743743,
66  -21.06224101826,
67  3.13082909833};
68 
69  const double c[9] = {0.3374754822726147,
70  0.9761690190917186,
71  0.1607979714918209,
72  0.0276438810333863,
73  0.0038405729373609,
74  0.0003951896511919,
75  0.0000321767881768,
76  0.0000002888167364,
77  0.0000003960315187};
78 
79  double r;
80  double x = u - 0.5;
81 
82  // Beasley-Springer
83  if (fabs(x) < 0.42) {
84 
85  double y = x * x;
86  r = x * (((a[3]*y+a[2])*y+a[1])*y+a[0]) /
87  ((((b[3]*y+b[2])*y+b[1])*y+b[0])*y+1.0);
88  }
89  else {// Moro
90  r = u;
91  if (x > 0.0)
92  r = 1.0 - u;
93  r = log(-log(r));
94  r = c[0] + r*(c[1]+r*(c[2]+r*(c[3]+r*(c[4]+r*(c[5]+r*(c[6]+
95  r*(c[7]+r*c[8])))))));
96  if (x < 0.0)
97  r = -r;
98  }
99 
100  return r;
101 }
102 int main(void)
103 {
104  int x = 0;
105  int i, j;
106  AVLFG state;
107  av_lfg_init(&state, 0xdeadbeef);
108  for (j = 0; j < 10000; j++) {
109  for (i = 0; i < 624; i++) {
110  //av_log(NULL, AV_LOG_ERROR, "%X\n", av_lfg_get(&state));
111  x += av_lfg_get(&state);
112  }
113  }
114  av_log(NULL, AV_LOG_ERROR, "final value:%X\n", x);
115 
116  /* BMG usage example */
117  {
118  double mean = 1000;
119  double stddev = 53;
120  double samp_mean = 0.0, samp_stddev = 0.0, QH = 0;
121  double Z, p_value = -1, tot_samp = 1000;
122  double *PRN_arr = av_malloc_array(tot_samp, sizeof(double));
123 
124  if (!PRN_arr) {
125  fprintf(stderr, "failed to allocate memory!\n");
126  return 1;
127  }
128 
129  av_lfg_init(&state, 42);
130  for (i = 0; i < tot_samp; i += 2) {
131  double bmg_out[2];
132  av_bmg_get(&state, bmg_out);
133  PRN_arr[i ] = bmg_out[0] * stddev + mean;
134  PRN_arr[i+1] = bmg_out[1] * stddev + mean;
135  samp_mean += PRN_arr[i] + PRN_arr[i+1];
136  samp_stddev += PRN_arr[i] * PRN_arr[i] + PRN_arr[i+1] * PRN_arr[i+1];
137  printf("PRN%d : %f\n"
138  "PRN%d : %f\n",
139  i, PRN_arr[i], i+1, PRN_arr[i+1]);
140  }
141  samp_mean /= tot_samp;
142  samp_stddev /= (tot_samp - 1);
143  samp_stddev -= (tot_samp * 1.0 / (tot_samp - 1))*samp_mean*samp_mean;
144  samp_stddev = sqrt(samp_stddev);
145  Z = (mean - samp_mean) / (stddev / sqrt(tot_samp));
146  {
147  int x, y, a, b, flag = 0;
148 
149  if (Z < 0.0) {
150  flag = !flag;
151  Z = Z * -1.0;
152  }
153 
154  a = (int)(Z * 100);
155  b = ((int)Z * 100);
156  x = Z * 10;
157  y = (b > 0) ? a % b : a;
158  y = y % 10;
159  if (x > 30 || y > 9) {
160  av_log(NULL, AV_LOG_INFO, "error: out of bounds! tried to access"
161  "Z_TABLE[%d][%d]\n", x, y);
162  goto SKIP;
163  }
164  p_value = flag ? 1 - Z_TABLE[x][y] : Z_TABLE[x][y];
165  }
166 
167 SKIP: for (i = 0; i < tot_samp; ++i) {
168 
169  if ( i < (tot_samp - 1)) {
170  double H_diff;
171  H_diff = inv_cdf((i + 2.0 - (3.0/8.0)) / (tot_samp + (1.0/4.0)));
172  H_diff -= inv_cdf((i + 1.0 - (3.0/8.0)) / (tot_samp + (1.0/4.0)));
173 
174  QH += ((PRN_arr[i + 1] - PRN_arr[i]) / H_diff);
175  }
176  }
177  QH = 1.0 - QH / ((tot_samp - 1.0) * samp_stddev);
178 
179  printf("sample mean : %f\n"
180  "true mean : %f\n"
181  "sample stddev: %f\n"
182  "true stddev : %f\n"
183  "z-score : %f\n"
184  "p-value : %f\n"
185  "QH[normality]: %f\n",
186  samp_mean, mean, samp_stddev, stddev, Z, p_value, QH);
187 
188  av_freep(&PRN_arr);
189  }
190  return 0;
191 }
av_lfg_init
av_cold void av_lfg_init(AVLFG *c, unsigned int seed)
Definition: lfg.c:32
u
#define u(width, name, range_min, range_max)
Definition: cbs_h2645.c:262
b
#define b
Definition: input.c:41
inv_cdf
static double inv_cdf(double u)
Definition: lfg.c:57
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
main
int main(void)
Definition: lfg.c:102
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
av_lfg_get
static unsigned int av_lfg_get(AVLFG *c)
Get the next random unsigned 32-bit number using an ALFG.
Definition: lfg.h:53
lfg.h
av_bmg_get
void av_bmg_get(AVLFG *lfg, double out[2])
Get the next two numbers generated by a Box-Muller Gaussian generator using the random numbers issued...
Definition: lfg.c:49
NULL
#define NULL
Definition: coverity.c:32
timer.h
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
AVLFG
Context structure for the Lagged Fibonacci PRNG.
Definition: lfg.h:33
state
static struct @314 state
printf
printf("static const uint8_t my_array[100] = {\n")
a
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:41
r
#define r
Definition: input.c:40
AV_LOG_INFO
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
Z_TABLE
static const double Z_TABLE[31][10]
Definition: lfg.c:23
flag
#define flag(name)
Definition: cbs_av1.c:556
log.h
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
av_malloc_array
#define av_malloc_array(a, b)
Definition: tableprint_vlc.h:32
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
int
int
Definition: ffmpeg_filter.c:192