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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] 6 .TH AUDIOCONVERT 1 "Feb 8, 2020" 7 .SH NAME 8 audioconvert \- convert audio file formats 9 .SH SYNOPSIS 10 .nf 11 \fBaudioconvert\fR [\fB-pF\fR] [\fB-f\fR \fIoutfmt\fR] [\fB-o\fR \fIoutfile\fR] 12 [ [\fB-i\fR \fIinfmt\fR] [\fIfile\fR]...] ... 13 .fi 14 15 .SH DESCRIPTION 16 \fBaudioconvert\fR converts audio data between a set of supported audio 17 encodings and file formats. It can be used to compress and decompress audio 18 data, to add audio file headers to raw audio data files, and to convert between 19 standard data encodings, such as u-law and linear PCM. 20 .sp 21 .LP 22 If no filenames are present, \fBaudioconvert\fR reads the data from the 23 standard input stream and writes an audio file to the standard output. 24 Otherwise, input files are processed in order, concatenated, and written to the 25 output file. 26 .sp 27 .LP 28 Input files are expected to contain audio file headers that identify the audio 29 data format. If the audio data does not contain a recognizable header, the 30 format must be specified with the \fB-i\fR option, using the \fBrate\fR, 31 \fBencoding\fR, and \fBchannels\fR keywords to identify the input data format. 32 .sp 33 .LP 34 The output file format is derived by updating the format of the first input 35 file with the format options in the \fB-f\fR specification. If \fB-p\fR is not 36 specified, all subsequent input files are converted to this resulting format 37 and concatenated together. The output file will contain an audio file header, 38 unless \fBformat\fR=\fIraw\fR is specified in the output format options. 39 .sp 40 .LP 41 Input files may be converted in place by using the \fB-p\fR option. When 42 \fB-p\fR is in effect, the format of each input file is modified according to 43 the \fB-f\fR option to determine the output format. The existing files are then 44 overwritten with the converted data. 45 .sp 46 .LP 47 The \fBfile\fR(1) command decodes and prints the audio data format of Sun audio 48 files. 49 .SH OPTIONS 50 The following options are supported: 51 .sp 52 .ne 2 53 .na 54 \fB\fB-p\fR\fR 55 .ad 56 .RS 14n 57 \fIIn Place\fR: The input files are individually converted to the format 58 specified by the \fB-f\fR option and rewritten. If a target file is a symbolic 59 link, the underlying file will be rewritten. The \fB-o\fR option may not be 60 specified with \fB-p\fR. 61 .RE 62 63 .sp 64 .ne 2 65 .na 66 \fB\fB-F\fR\fR 67 .ad 68 .RS 14n 69 \fIForce\fR: This option forces \fBaudioconvert\fR to ignore any file header 70 for input files whose format is specified by the \fB-i\fR option. If \fB-F\fR 71 is not specified, \fBaudioconvert\fR ignores the \fB-i\fR option for input 72 files that contain valid audio file headers. 73 .RE 74 75 .sp 76 .ne 2 77 .na 78 \fB\fB-f\fR \fIoutfmt\fR\fR 79 .ad 80 .RS 14n 81 \fIOutput Format\fR: This option is used to specify the file format and data 82 encoding of the output file. Defaults for unspecified fields are derived from 83 the input file format. Valid keywords and values are listed in the next 84 section. 85 .RE 86 87 .sp 88 .ne 2 89 .na 90 \fB\fB-o\fR \fIoutfile\fR\fR 91 .ad 92 .RS 14n 93 \fIOutput File\fR: All input files are concatenated, converted to the output 94 format, and written to the named output file. If \fB-o\fR and \fB-p\fR are not 95 specified, the concatenated output is written to the standard output. The 96 \fB-p\fR option may not be specified with \fB-o\fR. 97 .RE 98 99 .sp 100 .ne 2 101 .na 102 \fB\fB-i\fR \fIinfmt\fR\fR 103 .ad 104 .RS 14n 105 \fIInput Format\fR: This option is used to specify the data encoding of raw 106 input files. Ordinarily, the input data format is derived from the audio file 107 header. This option is required when converting audio data that is not preceded 108 by a valid audio file header. If \fB-i\fR is specified for an input file that 109 contains an audio file header, the input format string will be ignored, unless 110 \fB-F\fR is present. The format specification syntax is the same as the 111 \fB-f\fR output file format. 112 .sp 113 Multiple input formats may be specified. An input format describes all input 114 files following that specification, until a new input format is specified. 115 .RE 116 117 .sp 118 .ne 2 119 .na 120 \fB\fIfile\fR\fR 121 .ad 122 .RS 14n 123 \fIFile Specification\fR: The named audio files are concatenated, converted to 124 the output format, and written out. If no file name is present, or if the 125 special file name `\(mi' is specified, audio data is read from the standard 126 input. 127 .RE 128 129 .sp 130 .ne 2 131 .na 132 \fB\fB-?\fR\fR 133 .ad 134 .RS 14n 135 \fIHelp\fR: Prints a command line usage message. 136 .RE 137 138 .SS "Format Specification" 139 The syntax for the input and output format specification is: 140 .sp 141 .LP 142 \fIkeyword\fR=\fIvalue\fR[,\fIkeyword\fR=\fIvalue\fR \|.\|.\|.\|] 143 .sp 144 .LP 145 with no intervening whitespace. Unambiguous values may be used without the 146 preceding \fIkeyword\fR=. 147 .sp 148 .ne 2 149 .na 150 \fB\fBrate\fR\fR 151 .ad 152 .RS 12n 153 The audio sampling rate is specified in samples per second. If a number is 154 followed by the letter \fBk\fR, it is multiplied by 1000 (for example, 44.1k = 155 44100). Standard of the commonly used sample rates are: 8k, 16k, 32k, 44.1k, 156 and 48k. 157 .RE 158 159 .sp 160 .ne 2 161 .na 162 \fB\fBchannels\fR\fR 163 .ad 164 .RS 12n 165 The number of interleaved channels is specified as an integer. The words 166 \fBmono\fR and \fBstereo\fR may also be used to specify one and two channel 167 data, respectively. 168 .RE 169 170 .sp 171 .ne 2 172 .na 173 \fB\fBencoding\fR\fR 174 .ad 175 .RS 12n 176 This option specifies the digital audio data representation. Encodings 177 determine precision implicitly (\fBulaw\fR implies 8-bit precision) or 178 explicitly as part of the name (for example, \fBlinear16\fR). Valid encoding 179 values are: 180 .sp 181 .ne 2 182 .na 183 \fB\fBulaw\fR\fR 184 .ad 185 .RS 13n 186 \fBCCITT G.711\fR u-law encoding. This is an 8-bit format primarily used for 187 telephone quality speech. 188 .RE 189 190 .sp 191 .ne 2 192 .na 193 \fB\fBalaw\fR\fR 194 .ad 195 .RS 13n 196 \fBCCITT G.711\fR A-law encoding. This is an 8-bit format primarily used for 197 telephone quality speech in Europe. 198 .RE 199 200 .sp 201 .ne 2 202 .na 203 \fB\fBlinear8\fR,\fR 204 .ad 205 .br 206 .na 207 \fB\fBlinear16\fR,\fR 208 .ad 209 .br 210 .na 211 \fB\fBlinear32\fR\fR 212 .ad 213 .RS 13n 214 Linear Pulse Code Modulation (PCM) encoding. The name identifies the number of 215 bits of precision. \fBlinear16\fR is typically used for high quality audio 216 data. 217 .RE 218 219 .sp 220 .ne 2 221 .na 222 \fB\fBpcm\fR\fR 223 .ad 224 .RS 13n 225 Same as \fBlinear16\fR. 226 .RE 227 228 .sp 229 .ne 2 230 .na 231 \fB\fBg721\fR\fR 232 .ad 233 .RS 13n 234 \fBCCITT G.721\fR compression format. This encoding uses Adaptive Delta Pulse 235 Code Modulation (ADPCM) with 4-bit precision. It is primarily used for 236 compressing u-law voice data (achieving a 2:1 compression ratio). 237 .RE 238 239 .sp 240 .ne 2 241 .na 242 \fB\fBg723\fR\fR 243 .ad 244 .RS 13n 245 \fBCCITT G.723\fR compression format. This encoding uses Adaptive Delta Pulse 246 Code Modulation (ADPCM) with 3-bit precision. It is primarily used for 247 compressing u-law voice data (achieving an 8:3 compression ratio). The audio 248 quality is similar to \fBG.721,\fR but may result in lower quality when used 249 for non-speech data. 250 .RE 251 252 The following encoding values are also accepted as shorthand to set the sample 253 rate, channels, and encoding: 254 .sp 255 .ne 2 256 .na 257 \fB\fBvoice\fR\fR 258 .ad 259 .RS 9n 260 Equivalent to \fBencoding=ulaw,rate=8k,channels=mono\fR. 261 .RE 262 263 .sp 264 .ne 2 265 .na 266 \fB\fBcd\fR\fR 267 .ad 268 .RS 9n 269 Equivalent to \fBencoding=linear16,rate=44.1k,channels=stereo\fR. 270 .RE 271 272 .sp 273 .ne 2 274 .na 275 \fB\fBdat\fR\fR 276 .ad 277 .RS 9n 278 Equivalent to \fBencoding=linear16,rate=48k,channels=stereo\fR. 279 .RE 280 281 .RE 282 283 .sp 284 .ne 2 285 .na 286 \fB\fBformat\fR\fR 287 .ad 288 .RS 12n 289 This option specifies the audio file format. Valid formats are: 290 .sp 291 .ne 2 292 .na 293 \fB\fBsun\fR\fR 294 .ad 295 .RS 7n 296 Sun compatible file format (the default). 297 .RE 298 299 .sp 300 .ne 2 301 .na 302 \fB\fBraw\fR\fR 303 .ad 304 .RS 7n 305 Use this format when reading or writing raw audio data (with no audio header), 306 or in conjunction with an \fBoffset\fR to import a foreign audio file format. 307 .RE 308 309 .RE 310 311 .sp 312 .ne 2 313 .na 314 \fB\fBoffset\fR\fR 315 .ad 316 .RS 12n 317 (\fB-i\fR \fIonly\fR) Specifies a byte offset to locate the start of the audio 318 data. This option may be used to import audio data that contains an 319 unrecognized file header. 320 .RE 321 322 .SH USAGE 323 See \fBlargefile\fR(5) for the description of the behavior of 324 \fBaudioconvert\fR when encountering files greater than or equal to 2 Gbyte 325 (2^31 bytes). 326 .SH EXAMPLES 327 \fBExample 1 \fRRecording and compressing voice data before storing it 328 .sp 329 .LP 330 Record voice data and compress it before storing it to a file: 331 332 .sp 333 .in +2 334 .nf 335 example% \fBaudiorecord | audioconvert -f g721 > mydata.au\fR 336 .fi 337 .in -2 338 .sp 339 340 .LP 341 \fBExample 2 \fRConcatenating two audio files 342 .sp 343 .LP 344 Concatenate two Sun format audio files, regardless of their data format, and 345 output an 8-bit ulaw, 16 kHz, mono file: 346 347 .sp 348 .in +2 349 .nf 350 example% \fBaudioconvert -f ulaw,rate=16k,mono -o outfile.au infile1 infile2\fR 351 .fi 352 .in -2 353 .sp 354 355 .LP 356 \fBExample 3 \fRConverting a directory to Sun format 357 .sp 358 .LP 359 Convert a directory containing raw voice data files, in place, to Sun format 360 (adds a file header to each file): 361 362 .sp 363 .in +2 364 .nf 365 example% \fBaudioconvert -p -i voice -f sun *.au\fR 366 .fi 367 .in -2 368 .sp 369 370 .SH SEE ALSO 371 \fBaudioplay\fR(1), \fBaudiorecord\fR(1), \fBfile\fR(1), 372 \fBlargefile\fR(5) 373 .SH NOTES 374 The algorithm used for converting multi-channel data to mono is implemented by 375 simply summing the channels together. If the input data is perfectly in phase 376 (as would be the case if a mono file is converted to stereo and back to mono), 377 the resulting data may contain some distortion.