FFmpeg: tests/audiogen.c Source File

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audiogen.c

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1 /*

2 * Generate a synthetic stereo sound.

3 * NOTE: No floats are used to guarantee bitexact output.

4 *

6 *

7 * This file is part of FFmpeg.

8 *

9 * FFmpeg is free software; you can redistribute it and/or

10 * modify it under the terms of the GNU Lesser General Public

11 * License as published by the Free Software Foundation; either

12 * version 2.1 of the License, or (at your option) any later version.

13 *

14 * FFmpeg is distributed in the hope that it will be useful,

15 * but WITHOUT ANY WARRANTY; without even the implied warranty of

16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

17 * Lesser General Public License for more details.

18 *

19 * You should have received a copy of the GNU Lesser General Public

20 * License along with FFmpeg; if not, write to the Free Software

21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

22 */

24 #include <stdlib.h>

25 #include <stdint.h>

26 #include <stdio.h>

27 #include <string.h>

29 #define MAX_CHANNELS 12

31 static unsigned int myrnd(unsigned int *seed_ptr, int n)

32 {

33 unsigned int seed, val;

35 seed = *seed_ptr;

36 seed = (seed * 314159) + 1;

37 if (n == 256) {

38 val = seed >> 24;

39 } else {

40 val = seed % n;

41 }

42 *seed_ptr = seed;

43 return val;

44 }

46 #define FRAC_BITS 16

47 #define FRAC_ONE (1 << FRAC_BITS)

49 #define COS_TABLE_BITS 7

51 /* integer cosine */

52 static const unsigned short cos_table[(1 << COS_TABLE_BITS) + 2] = {

53 0x8000, 0x7ffe, 0x7ff6, 0x7fea, 0x7fd9, 0x7fc2, 0x7fa7, 0x7f87,

54 0x7f62, 0x7f38, 0x7f0a, 0x7ed6, 0x7e9d, 0x7e60, 0x7e1e, 0x7dd6,

55 0x7d8a, 0x7d3a, 0x7ce4, 0x7c89, 0x7c2a, 0x7bc6, 0x7b5d, 0x7aef,

56 0x7a7d, 0x7a06, 0x798a, 0x790a, 0x7885, 0x77fb, 0x776c, 0x76d9,

57 0x7642, 0x75a6, 0x7505, 0x7460, 0x73b6, 0x7308, 0x7255, 0x719e,

58 0x70e3, 0x7023, 0x6f5f, 0x6e97, 0x6dca, 0x6cf9, 0x6c24, 0x6b4b,

59 0x6a6e, 0x698c, 0x68a7, 0x67bd, 0x66d0, 0x65de, 0x64e9, 0x63ef,

60 0x62f2, 0x61f1, 0x60ec, 0x5fe4, 0x5ed7, 0x5dc8, 0x5cb4, 0x5b9d,

61 0x5a82, 0x5964, 0x5843, 0x571e, 0x55f6, 0x54ca, 0x539b, 0x5269,

62 0x5134, 0x4ffb, 0x4ec0, 0x4d81, 0x4c40, 0x4afb, 0x49b4, 0x486a,

63 0x471d, 0x45cd, 0x447b, 0x4326, 0x41ce, 0x4074, 0x3f17, 0x3db8,

64 0x3c57, 0x3af3, 0x398d, 0x3825, 0x36ba, 0x354e, 0x33df, 0x326e,

65 0x30fc, 0x2f87, 0x2e11, 0x2c99, 0x2b1f, 0x29a4, 0x2827, 0x26a8,

66 0x2528, 0x23a7, 0x2224, 0x209f, 0x1f1a, 0x1d93, 0x1c0c, 0x1a83,

67 0x18f9, 0x176e, 0x15e2, 0x1455, 0x12c8, 0x113a, 0x0fab, 0x0e1c,

68 0x0c8c, 0x0afb, 0x096b, 0x07d9, 0x0648, 0x04b6, 0x0324, 0x0192,

69 0x0000, 0x0000,

70 };

72 #define CSHIFT (FRAC_BITS - COS_TABLE_BITS - 2)

74 static int int_cos(int a)

75 {

76 int neg, v, f;

77 const unsigned short *p;

79 a = a & (FRAC_ONE - 1); /* modulo 2 * pi */

80 if (a >= (FRAC_ONE / 2))

81 a = FRAC_ONE - a;

82 neg = 0;

83 if (a > (FRAC_ONE / 4)) {

84 neg = -1;

85 a = (FRAC_ONE / 2) - a;

86 }

87 p = cos_table + (a >> CSHIFT);

88 /* linear interpolation */

89 f = a & ((1 << CSHIFT) - 1);

90 v = p[0] + (((p[1] - p[0]) * f + (1 << (CSHIFT - 1))) >> CSHIFT);

91 v = (v ^ neg) - neg;

92 v = v << (FRAC_BITS - 15);

93 return v;

94 }

96 FILE *outfile;

98 static void put16(int16_t v)

99 {

100 fputc( v & 0xff, outfile);

101 fputc((v >> 8) & 0xff, outfile);

102 }

103

104 static void put32(uint32_t v)

105 {

106 fputc( v & 0xff, outfile);

107 fputc((v >> 8) & 0xff, outfile);

108 fputc((v >> 16) & 0xff, outfile);

109 fputc((v >> 24) & 0xff, outfile);

110 }

111

112 #define HEADER_SIZE 46

113 #define FMT_SIZE 18

114 #define SAMPLE_SIZE 2

115 #define WFORMAT_PCM 0x0001

116

117 static void put_wav_header(int sample_rate, int channels, int nb_samples)

118 {

119 int block_align = SAMPLE_SIZE * channels;

120 int data_size = block_align * nb_samples;

121

122 fputs("RIFF", outfile);

123 put32(HEADER_SIZE + data_size);

124 fputs("WAVEfmt ", outfile);

125 put32(FMT_SIZE);

126 put16(WFORMAT_PCM);

127 put16(channels);

128 put32(sample_rate);

129 put32(block_align * sample_rate);

130 put16(block_align);

131 put16(SAMPLE_SIZE * 8);

132 put16(0);

133 fputs("data", outfile);

134 put32(data_size);

135 }

136

137 int main(int argc, char **argv)

138 {

139 int i, a, v, j, f, amp, ampa;

140 unsigned int seed = 1;

141 int tabf1[MAX_CHANNELS], tabf2[MAX_CHANNELS];

142 int taba[MAX_CHANNELS];

143 int sample_rate = 44100;

144 int nb_channels = 2;

145 char *ext;

146

147 if (argc < 2 || argc > 5) {

148 printf("usage: %s file [<sample rate> [<channels>] [<random seed>]]\n"

149 "generate a test raw 16 bit audio stream\n"

150 "If the file extension is .wav a WAVE header will be added.\n"

151 "default: 44100 Hz stereo\n", argv[0]);

152 exit(1);

153 }

154

155 if (argc > 2) {

156 sample_rate = atoi(argv[2]);

157 if (sample_rate <= 0) {

158 fprintf(stderr, "invalid sample rate: %d\n", sample_rate);

159 return 1;

160 }

161 }

162

163 if (argc > 3) {

164 nb_channels = atoi(argv[3]);

165 if (nb_channels < 1 || nb_channels > MAX_CHANNELS) {

166 fprintf(stderr, "invalid number of channels: %d\n", nb_channels);

167 return 1;

168 }

169 }

170

171 if (argc > 4)

172 seed = atoi(argv[4]);

173

174 outfile = fopen(argv[1], "wb");

175 if (!outfile) {

176 perror(argv[1]);

177 return 1;

178 }

179

180 if ((ext = strrchr(argv[1], '.')) && !strcmp(ext, ".wav"))

181 put_wav_header(sample_rate, nb_channels, 6 * sample_rate);

182

183 /* 1 second of single freq sine at 1000 Hz */

184 a = 0;

185 for (i = 0; i < 1 * sample_rate; i++) {

186 v = (int_cos(a) * 10000) >> FRAC_BITS;

187 for (j = 0; j < nb_channels; j++)

188 put16(v);

189 a += (1000 * FRAC_ONE) / sample_rate;

190 }

191

192 /* 1 second of varying frequency between 100 and 10000 Hz */

193 a = 0;

194 for (i = 0; i < 1 * sample_rate; i++) {

195 v = (int_cos(a) * 10000) >> FRAC_BITS;

196 for (j = 0; j < nb_channels; j++)

197 put16(v);

198 f = 100 + (((10000 - 100) * i) / sample_rate);

199 a += (f * FRAC_ONE) / sample_rate;

200 }

201

202 /* 0.5 second of low amplitude white noise */

203 for (i = 0; i < sample_rate / 2; i++) {

204 v = myrnd(&seed, 20000) - 10000;

205 for (j = 0; j < nb_channels; j++)

206 put16(v);

207 }

208

209 /* 0.5 second of high amplitude white noise */

210 for (i = 0; i < sample_rate / 2; i++) {

211 v = myrnd(&seed, 65535) - 32768;

212 for (j = 0; j < nb_channels; j++)

213 put16(v);

214 }

215

216 /* 1 second of unrelated ramps for each channel */

217 for (j = 0; j < nb_channels; j++) {

218 taba[j] = 0;

219 tabf1[j] = 100 + myrnd(&seed, 5000);

220 tabf2[j] = 100 + myrnd(&seed, 5000);

221 }

222 for (i = 0; i < 1 * sample_rate; i++) {

223 for (j = 0; j < nb_channels; j++) {

224 v = (int_cos(taba[j]) * 10000) >> FRAC_BITS;

225 put16(v);

226 f = tabf1[j] + (((tabf2[j] - tabf1[j]) * i) / sample_rate);

227 taba[j] += (f * FRAC_ONE) / sample_rate;

228 }

229 }

230

231 /* 2 seconds of 500 Hz with varying volume */

232 a = 0;

233 ampa = 0;

234 for (i = 0; i < 2 * sample_rate; i++) {

235 for (j = 0; j < nb_channels; j++) {

236 amp = ((FRAC_ONE + int_cos(ampa)) * 5000) >> FRAC_BITS;

237 if (j & 1)

238 amp = 10000 - amp;

239 v = (int_cos(a) * amp) >> FRAC_BITS;

240 put16(v);

241 a += (500 * FRAC_ONE) / sample_rate;

242 ampa += (2 * FRAC_ONE) / sample_rate;

243 }

244 }

245

246 fclose(outfile);

247 return 0;

248 }

FRAC_BITS

#define FRAC_BITS

Definition: audiogen.c:46

outfile

FILE * outfile

Definition: audiogen.c:96

sample_rate

Definition: ffmpeg_filter.c:153

SAMPLE_SIZE

#define SAMPLE_SIZE

Definition: audiogen.c:114

FMT_SIZE

#define FMT_SIZE

Definition: audiogen.c:113

val

static double val(void *priv, double ch)

Definition: aeval.c:76

put16

static void put16(int16_t v)

Definition: audiogen.c:98

int_cos

static int int_cos(int a)

Definition: audiogen.c:74

cos_table

static const unsigned short cos_table[(1<< COS_TABLE_BITS)+2]

Definition: audiogen.c:52

CSHIFT

#define CSHIFT

Definition: audiogen.c:72

channels

Definition: aptx.h:33

WFORMAT_PCM

#define WFORMAT_PCM

Definition: audiogen.c:115

#define f(width, name)

Definition: cbs_vp9.c:255

seed

static unsigned int seed

Definition: videogen.c:78

printf

printf("static const uint8_t my_array[100] = {\n")

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

FRAC_ONE

#define FRAC_ONE

Definition: audiogen.c:47

main

int main(int argc, char **argv)

Definition: audiogen.c:137

COS_TABLE_BITS

#define COS_TABLE_BITS

Definition: audiogen.c:49

#define i(width, name, range_min, range_max)

Definition: cbs_h2645.c:271