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record.c revision 1.21
      1 /*	$NetBSD: record.c,v 1.21 2002/01/15 23:48:53 mrg Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1999 Matthew R. Green
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. The name of the author may not be used to endorse or promote products
     16  *    derived from this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     23  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     24  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     25  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     26  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  * SUCH DAMAGE.
     29  */
     30 
     31 /*
     32  * SunOS compatible audiorecord(1)
     33  */
     34 
     35 #include <sys/types.h>
     36 #include <sys/audioio.h>
     37 #include <sys/ioctl.h>
     38 #include <sys/time.h>
     39 #include <sys/uio.h>
     40 
     41 #include <err.h>
     42 #include <fcntl.h>
     43 #include <paths.h>
     44 #include <signal.h>
     45 #include <stdio.h>
     46 #include <stdlib.h>
     47 #include <string.h>
     48 #include <unistd.h>
     49 
     50 #include "libaudio.h"
     51 #include "auconv.h"
     52 
     53 audio_info_t info, oinfo;
     54 ssize_t	total_size = -1;
     55 const char *device;
     56 const char *ctldev;
     57 int	format = AUDIO_FORMAT_SUN;
     58 char	*header_info;
     59 char	default_info[8] = { '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0' };
     60 int	audiofd, ctlfd, outfd;
     61 int	qflag, aflag, fflag;
     62 int	verbose;
     63 int	monitor_gain, omonitor_gain;
     64 int	gain;
     65 int	balance;
     66 int	port;
     67 int	encoding;
     68 char	*encoding_str;
     69 int	precision;
     70 int	sample_rate;
     71 int	channels;
     72 struct timeval record_time;
     73 struct timeval start_time;	/* XXX because that's what gettimeofday returns */
     74 
     75 void (*conv_func) (u_char *, size_t);
     76 
     77 void usage (void);
     78 int main (int, char *[]);
     79 int timeleft (struct timeval *, struct timeval *);
     80 void cleanup (int) __attribute__((__noreturn__));
     81 int write_header_sun (void **, size_t *, int *);
     82 int write_header_wav (void **, size_t *, int *);
     83 void write_header (void);
     84 void rewrite_header (void);
     85 
     86 int
     87 main(argc, argv)
     88 	int argc;
     89 	char *argv[];
     90 {
     91 	char	*buffer;
     92 	size_t	len, bufsize;
     93 	int	ch, no_time_limit = 1;
     94 
     95 	while ((ch = getopt(argc, argv, "ab:C:F:c:d:e:fhi:m:P:p:qt:s:Vv:")) != -1) {
     96 		switch (ch) {
     97 		case 'a':
     98 			aflag++;
     99 			break;
    100 		case 'b':
    101 			decode_int(optarg, &balance);
    102 			if (balance < 0 || balance > 63)
    103 				errx(1, "balance must be between 0 and 63\n");
    104 			break;
    105 		case 'C':
    106 			ctldev = optarg;
    107 			break;
    108 		case 'F':
    109 			format = audio_format_from_str(optarg);
    110 			if (format < 0)
    111 				errx(1, "Unknown audio format; "
    112 				    "supported formats: \"sun\" and \"wav\"");
    113 			break;
    114 		case 'c':
    115 			decode_int(optarg, &channels);
    116 			if (channels < 0 || channels > 16)
    117 				errx(1, "channels must be between 0 and 16\n");
    118 			break;
    119 		case 'd':
    120 			device = optarg;
    121 			break;
    122 		case 'e':
    123 			encoding_str = optarg;
    124 			break;
    125 		case 'f':
    126 			fflag++;
    127 			break;
    128 		case 'i':
    129 			header_info = optarg;
    130 			break;
    131 		case 'm':
    132 			decode_int(optarg, &monitor_gain);
    133 			if (monitor_gain < 0 || monitor_gain > 255)
    134 				errx(1, "monitor volume must be between 0 and 255\n");
    135 			break;
    136 		case 'P':
    137 			decode_int(optarg, &precision);
    138 			if (precision != 4 && precision != 8 &&
    139 			    precision != 16 && precision != 24 &&
    140 			    precision != 32)
    141 				errx(1, "precision must be between 4, 8, 16, 24 or 32");
    142 			break;
    143 		case 'p':
    144 			len = strlen(optarg);
    145 
    146 			if (strncmp(optarg, "mic", len) == 0)
    147 				port |= AUDIO_MICROPHONE;
    148 			else if (strncmp(optarg, "cd", len) == 0 ||
    149 			           strncmp(optarg, "internal-cd", len) == 0)
    150 				port |= AUDIO_CD;
    151 			else if (strncmp(optarg, "line", len) == 0)
    152 				port |= AUDIO_LINE_IN;
    153 			else
    154 				errx(1,
    155 			    "port must be `cd', `internal-cd', `mic', or `line'");
    156 			break;
    157 		case 'q':
    158 			qflag++;
    159 			break;
    160 		case 's':
    161 			decode_int(optarg, &sample_rate);
    162 			if (sample_rate < 0 || sample_rate > 48000 * 2)	/* XXX */
    163 				errx(1, "sample rate must be between 0 and 96000\n");
    164 			break;
    165 		case 't':
    166 			no_time_limit = 0;
    167 			decode_time(optarg, &record_time);
    168 			break;
    169 		case 'V':
    170 			verbose++;
    171 			break;
    172 		case 'v':
    173 			decode_int(optarg, &gain);
    174 			if (gain < 0 || gain > 255)
    175 				errx(1, "volume must be between 0 and 255\n");
    176 			break;
    177 		/* case 'h': */
    178 		default:
    179 			usage();
    180 			/* NOTREACHED */
    181 		}
    182 	}
    183 	argc -= optind;
    184 	argv += optind;
    185 
    186 	/*
    187 	 * open the audio device, and control device
    188 	 */
    189 	if (device == NULL && (device = getenv("AUDIODEVICE")) == NULL &&
    190 	    (device = getenv("AUDIODEV")) == NULL) /* Sun compatibility */
    191 		device = _PATH_AUDIO;
    192 	if (ctldev == NULL && (ctldev = getenv("AUDIOCTLDEVICE")) == NULL)
    193 		ctldev = _PATH_AUDIOCTL;
    194 
    195 	audiofd = open(device, O_RDONLY);
    196 	if (audiofd < 0)
    197 		err(1, "failed to open %s", device);
    198 	ctlfd = open(ctldev, O_RDWR);
    199 	if (ctlfd < 0)
    200 		err(1, "failed to open %s", ctldev);
    201 
    202 	/*
    203 	 * work out the buffer size to use, and allocate it.  also work out
    204 	 * what the old monitor gain value is, so that we can reset it later.
    205 	 */
    206 	if (ioctl(ctlfd, AUDIO_GETINFO, &oinfo) < 0)
    207 		err(1, "failed to get audio info");
    208 	bufsize = oinfo.record.buffer_size;
    209 	if (bufsize < 32 * 1024)
    210 		bufsize = 32 * 1024;
    211 	omonitor_gain = oinfo.monitor_gain;
    212 
    213 	buffer = malloc(bufsize);
    214 	if (buffer == NULL)
    215 		err(1, "couldn't malloc buffer of %d size", (int)bufsize);
    216 
    217 	/*
    218 	 * open the output file
    219 	 */
    220 	if (argc != 1)
    221 		usage();
    222 	if (argv[0][0] != '-' && argv[0][1] != '\0') {
    223 		outfd = open(*argv, O_CREAT|(aflag ? O_APPEND : O_TRUNC)|O_WRONLY, 0666);
    224 		if (outfd < 0)
    225 			err(1, "could not open %s", *argv);
    226 	} else
    227 		outfd = STDOUT_FILENO;
    228 
    229 	/*
    230 	 * convert the encoding string into a value.
    231 	 */
    232 	if (encoding_str) {
    233 		encoding = audio_enc_to_val(encoding_str);
    234 		if (encoding == -1)
    235 			errx(1, "unknown encoding, bailing...");
    236 	}
    237 	else
    238 		encoding = AUDIO_ENCODING_ULAW;
    239 
    240 	/*
    241 	 * set up audio device for recording with the speified parameters
    242 	 */
    243 	AUDIO_INITINFO(&info);
    244 
    245 	/*
    246 	 * for these, get the current values for stuffing into the header
    247 	 */
    248 #define SETINFO(x)	if (x) info.record.x = x; else x = oinfo.record.x
    249 	SETINFO (sample_rate);
    250 	SETINFO (channels);
    251 	SETINFO (precision);
    252 	SETINFO (encoding);
    253 	SETINFO (gain);
    254 	SETINFO (port);
    255 	SETINFO (balance);
    256 #undef SETINFO
    257 
    258 	if (monitor_gain)
    259 		info.monitor_gain = monitor_gain;
    260 	else
    261 		monitor_gain = oinfo.monitor_gain;
    262 
    263 	info.mode = AUMODE_RECORD;
    264 	if (ioctl(ctlfd, AUDIO_SETINFO, &info) < 0)
    265 		err(1, "failed to reset audio info");
    266 
    267 	signal(SIGINT, cleanup);
    268 	write_header();
    269 	total_size = 0;
    270 
    271 	(void)gettimeofday(&start_time, NULL);
    272 	while (no_time_limit || timeleft(&start_time, &record_time)) {
    273 		if (read(audiofd, buffer, bufsize) != bufsize)
    274 			err(1, "read failed");
    275 		if (conv_func)
    276 			(*conv_func)(buffer, bufsize);
    277 		if (write(outfd, buffer, bufsize) != bufsize)
    278 			err(1, "write failed");
    279 		total_size += bufsize;
    280 	}
    281 	cleanup(0);
    282 }
    283 
    284 int
    285 timeleft(start_tvp, record_tvp)
    286 	struct timeval *start_tvp;
    287 	struct timeval *record_tvp;
    288 {
    289 	struct timeval now, diff;
    290 
    291 	(void)gettimeofday(&now, NULL);
    292 	timersub(&now, start_tvp, &diff);
    293 	timersub(record_tvp, &diff, &now);
    294 
    295 	return (now.tv_sec > 0 || (now.tv_sec == 0 && now.tv_usec > 0));
    296 }
    297 
    298 void
    299 cleanup(signo)
    300 	int signo;
    301 {
    302 
    303 	close(audiofd);
    304 	rewrite_header();
    305 	close(outfd);
    306 	if (omonitor_gain) {
    307 		AUDIO_INITINFO(&info);
    308 		info.monitor_gain = omonitor_gain;
    309 		if (ioctl(ctlfd, AUDIO_SETINFO, &info) < 0)
    310 			err(1, "failed to reset audio info");
    311 	}
    312 	close(ctlfd);
    313 	exit(0);
    314 }
    315 
    316 int
    317 write_header_sun(hdrp, lenp, leftp)
    318 	void **hdrp;
    319 	size_t *lenp;
    320 	int *leftp;
    321 {
    322 	static int warned = 0;
    323 	static sun_audioheader auh;
    324 	int sunenc, oencoding = encoding;
    325 
    326 	if (encoding == AUDIO_ENCODING_ULINEAR_LE) {
    327 		if (precision == 16)
    328 			conv_func = swap_bytes;
    329 		else if (precision == 32)
    330 			conv_func = swap_bytes32;
    331 		if (conv_func)
    332 			encoding = AUDIO_ENCODING_SLINEAR_BE;
    333 	} else if (encoding == AUDIO_ENCODING_ULINEAR_BE) {
    334 		if (precision == 16)
    335 			conv_func = change_sign16_be;
    336 		else if (precision == 32)
    337 			conv_func = change_sign32_be;
    338 		if (conv_func)
    339 			encoding = AUDIO_ENCODING_SLINEAR_BE;
    340 	} else if (encoding == AUDIO_ENCODING_SLINEAR_LE) {
    341 		if (precision == 16)
    342 			conv_func = change_sign16_swap_bytes_le;
    343 		else if (precision == 32)
    344 			conv_func = change_sign32_swap_bytes_le;
    345 		if (conv_func)
    346 			encoding = AUDIO_ENCODING_SLINEAR_BE;
    347 	}
    348 
    349 	/* if we can't express this as a Sun header, don't write any */
    350 	if (audio_encoding_to_sun(encoding, precision, &sunenc) != 0) {
    351 		if (!qflag && !warned)
    352 			warnx("failed to convert to sun encoding from %d:%d; "
    353 			      "Sun audio header not written",
    354 			      oencoding, precision);
    355 		conv_func = 0;
    356 		warned = 1;
    357 		return -1;
    358 	}
    359 
    360 	auh.magic = htonl(AUDIO_FILE_MAGIC);
    361 	if (outfd == STDOUT_FILENO)
    362 		auh.data_size = htonl(AUDIO_UNKNOWN_SIZE);
    363 	else
    364 		auh.data_size = htonl(total_size);
    365 	auh.encoding = htonl(sunenc);
    366 	auh.sample_rate = htonl(sample_rate);
    367 	auh.channels = htonl(channels);
    368 	if (header_info) {
    369 		int 	len, infolen;
    370 
    371 		infolen = ((len = strlen(header_info)) + 7) & 0xfffffff8;
    372 		*leftp = infolen - len;
    373 		auh.hdr_size = htonl(sizeof(auh) + infolen);
    374 	} else {
    375 		*leftp = sizeof(default_info);
    376 		auh.hdr_size = htonl(sizeof(auh) + *leftp);
    377 	}
    378 	*(sun_audioheader **)hdrp = &auh;
    379 	*lenp = sizeof auh;
    380 	return 0;
    381 }
    382 
    383 int
    384 write_header_wav(hdrp, lenp, leftp)
    385 	void **hdrp;
    386 	size_t *lenp;
    387 	int *leftp;
    388 {
    389 	/*
    390 	 * WAV header we write looks like this:
    391 	 *
    392 	 *      bytes   purpose
    393 	 *      0-3     "RIFF"
    394 	 *      4-7     file length (minus 8)
    395 	 *      8-15    "WAVEfmt "
    396 	 *      16-19   format size
    397 	 *      20-21   format tag
    398 	 *      22-23   number of channels
    399 	 *      24-27   sample rate
    400 	 *      28-31   average bytes per second
    401 	 *      32-33   block alignment
    402 	 *      34-35   bits per sample
    403 	 *
    404 	 * then for ULAW and ALAW outputs, we have an extended chunk size
    405 	 * and a WAV "fact" to add:
    406 	 *
    407 	 *      36-37   length of extension (== 0)
    408 	 *      38-41   "fact"
    409 	 *      42-45   fact size
    410 	 *      46-49   number of samples written
    411 	 *      50-53   "data"
    412 	 *      54-57   data length
    413 	 *      58-     raw audio data
    414 	 *
    415 	 * for PCM outputs we have just the data remaining:
    416 	 *
    417 	 *      36-39   "data"
    418 	 *      40-43   data length
    419 	 *      44-     raw audio data
    420 	 *
    421 	 *	RIFF\^@^C^@WAVEfmt ^P^@^@^@^A^@^B^@D<AC>^@^@^P<B1>^B^@^D^@^P^@data^@^@^C^@^@^@^@^@^@^@^@^@^@
    422 	 */
    423 	char	wavheaderbuf[64], *p = wavheaderbuf;
    424 	const char *riff = "RIFF",
    425 	    *wavefmt = "WAVEfmt ",
    426 	    *fact = "fact",
    427 	    *data = "data";
    428 	u_int32_t filelen, fmtsz, sps, abps, factsz = 4, nsample, datalen;
    429 	u_int16_t fmttag, nchan, align, bps, extln = 0;
    430 
    431 	if (header_info)
    432 		warnx("header information not supported for WAV");
    433 	*leftp = NULL;
    434 
    435 	switch (precision) {
    436 	case 8:
    437 		bps = 8;
    438 		break;
    439 	case 16:
    440 		bps = 16;
    441 		break;
    442 	case 32:
    443 		bps = 32;
    444 		break;
    445 	default:
    446 		{
    447 			static int warned = 0;
    448 
    449 			if (warned == 0) {
    450 				warnx("can not support precision of %d\n", precision);
    451 				warned = 1;
    452 			}
    453 		}
    454 		return (-1);
    455 	}
    456 
    457 	switch (encoding) {
    458 	case AUDIO_ENCODING_ULAW:
    459 		fmttag = WAVE_FORMAT_MULAW;
    460 		fmtsz = 18;
    461 		align = channels;
    462 		break;
    463 	case AUDIO_ENCODING_ALAW:
    464 		fmttag = WAVE_FORMAT_ALAW;
    465 		fmtsz = 18;
    466 		align = channels;
    467 		break;
    468 	/*
    469 	 * we could try to support RIFX but it seems to be more portable
    470 	 * to output little-endian data for WAV files.
    471 	 */
    472 	case AUDIO_ENCODING_ULINEAR_BE:
    473 		if (bps == 16)
    474 			conv_func = change_sign16_swap_bytes_be;
    475 		else if (bps == 32)
    476 			conv_func = change_sign32_swap_bytes_be;
    477 		goto fmt_pcm;
    478 	case AUDIO_ENCODING_SLINEAR_BE:
    479 		if (bps == 16)
    480 			conv_func = swap_bytes;
    481 		else if (bps == 32)
    482 			conv_func = swap_bytes32;
    483 		goto fmt_pcm;
    484 	case AUDIO_ENCODING_ULINEAR_LE:
    485 		if (bps == 16)
    486 			conv_func = change_sign16_le;
    487 		else if (bps == 32)
    488 			conv_func = change_sign32_le;
    489 		/* FALLTHROUGH */
    490 	case AUDIO_ENCODING_SLINEAR_LE:
    491 	case AUDIO_ENCODING_PCM16:
    492 fmt_pcm:
    493 		fmttag = WAVE_FORMAT_PCM;
    494 		fmtsz = 16;
    495 		align = channels * (bps / 8);
    496 		break;
    497 	default:
    498 		{
    499 			static int warned = 0;
    500 
    501 			if (warned == 0) {
    502 				warnx("can not support encoding of %s\n", wav_enc_from_val(encoding));
    503 				warned = 1;
    504 			}
    505 		}
    506 		return (-1);
    507 	}
    508 
    509 	nchan = channels;
    510 	sps = sample_rate;
    511 
    512 	/* data length */
    513 	if (outfd == STDOUT_FILENO)
    514 		datalen = 0;
    515 	else
    516 		datalen = total_size;
    517 
    518 	/* file length */
    519 	filelen = 4 + (8 + fmtsz) + (8 + datalen);
    520 	if (fmttag != WAVE_FORMAT_PCM)
    521 		filelen += 8 + factsz;
    522 
    523 	abps = (double)align*sample_rate / (double)1 + 0.5;
    524 
    525 	nsample = (datalen / bps) / sample_rate;
    526 
    527 	/*
    528 	 * now we've calculated the info, write it out!
    529 	 */
    530 #define put32(x) do { \
    531 	u_int32_t _f; \
    532 	putle32(_f, (x)); \
    533 	memcpy(p, &_f, 4); \
    534 } while (0)
    535 #define put16(x) do { \
    536 	u_int16_t _f; \
    537 	putle16(_f, (x)); \
    538 	memcpy(p, &_f, 2); \
    539 } while (0)
    540 	memcpy(p, riff, 4);
    541 	p += 4;				/* 4 */
    542 	put32(filelen);
    543 	p += 4;				/* 8 */
    544 	memcpy(p, wavefmt, 8);
    545 	p += 8;				/* 16 */
    546 	put32(fmtsz);
    547 	p += 4;				/* 20 */
    548 	put16(fmttag);
    549 	p += 2;				/* 22 */
    550 	put16(nchan);
    551 	p += 2;				/* 24 */
    552 	put32(sps);
    553 	p += 4;				/* 28 */
    554 	put32(abps);
    555 	p += 4;				/* 32 */
    556 	put16(align);
    557 	p += 2;				/* 34 */
    558 	put16(bps);
    559 	p += 2;				/* 36 */
    560 	/* NON PCM formats have an extended chunk; write it */
    561 	if (fmttag != WAVE_FORMAT_PCM) {
    562 		put16(extln);
    563 		p += 2;			/* 38 */
    564 		memcpy(p, fact, 4);
    565 		p += 4;			/* 42 */
    566 		put32(factsz);
    567 		p += 4;			/* 46 */
    568 		put32(nsample);
    569 		p += 4;			/* 50 */
    570 	}
    571 	memcpy(p, data, 4);
    572 	p += 4;				/* 40/54 */
    573 	put32(datalen);
    574 	p += 4;				/* 44/58 */
    575 #undef put32
    576 #undef put16
    577 
    578 	*hdrp = wavheaderbuf;
    579 	*lenp = (p - wavheaderbuf);
    580 
    581 	return 0;
    582 }
    583 
    584 void
    585 write_header()
    586 {
    587 	struct iovec iv[3];
    588 	int veclen, left, tlen;
    589 	void *hdr;
    590 	size_t hdrlen;
    591 
    592 	switch (format) {
    593 	case AUDIO_FORMAT_SUN:
    594 		if (write_header_sun(&hdr, &hdrlen, &left) != 0)
    595 			return;
    596 		break;
    597 	case AUDIO_FORMAT_WAV:
    598 		if (write_header_wav(&hdr, &hdrlen, &left) != 0)
    599 			return;
    600 		break;
    601 	case AUDIO_FORMAT_NONE:
    602 		return;
    603 	default:
    604 		errx(1, "unknown audio format");
    605 	}
    606 
    607 	veclen = 0;
    608 	tlen = 0;
    609 
    610 	if (hdrlen != 0) {
    611 		iv[veclen].iov_base = hdr;
    612 		iv[veclen].iov_len = hdrlen;
    613 		tlen += iv[veclen++].iov_len;
    614 	}
    615 	if (header_info) {
    616 		iv[veclen].iov_base = header_info;
    617 		iv[veclen].iov_len = (int)strlen(header_info) + 1;
    618 		tlen += iv[veclen++].iov_len;
    619 	}
    620 	if (left) {
    621 		iv[veclen].iov_base = default_info;
    622 		iv[veclen].iov_len = left;
    623 		tlen += iv[veclen++].iov_len;
    624 	}
    625 
    626 	if (tlen == 0)
    627 		return;
    628 
    629 	if (writev(outfd, iv, veclen) != tlen)
    630 		err(1, "could not write audio header");
    631 }
    632 
    633 void
    634 rewrite_header()
    635 {
    636 
    637 	/* can't do this here! */
    638 	if (outfd == STDOUT_FILENO)
    639 		return;
    640 
    641 	if (lseek(outfd, SEEK_SET, 0) < 0)
    642 		err(1, "could not seek to start of file for header rewrite");
    643 	write_header();
    644 }
    645 
    646 void
    647 usage()
    648 {
    649 
    650 	fprintf(stderr, "Usage: %s [-afhqV] [options] {files ...|-}\n",
    651 	    getprogname());
    652 	fprintf(stderr, "Options:\n\t"
    653 	    "-C audio control device\n\t"
    654 	    "-F format\n\t"
    655 	    "-b balance (0-63)\n\t"
    656 	    "-c channels\n\t"
    657 	    "-d audio device\n\t"
    658 	    "-e encoding\n\t"
    659 	    "-i header information\n\t"
    660 	    "-m monitor volume\n\t"
    661 	    "-P precision bits (4, 8, 16, 24 or 32)\n\t"
    662 	    "-p input port\n\t"
    663 	    "-s sample rate\n\t"
    664 	    "-t recording time\n\t"
    665 	    "-v volume\n");
    666 	exit(EXIT_FAILURE);
    667 }
    668