-
Notifications
You must be signed in to change notification settings - Fork 4
/
sph2pipe.c
629 lines (582 loc) · 20.5 KB
/
sph2pipe.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
/*************************************************************
* Source File: sph2pipe.c
* Compilation: gcc -o sph2pipe sph2pipe.c shorten_x.c file_headers.c
* Authors: Dave Graff, Willie Dong; LDC, University of Pennsylvania
* Purpose: multi-platform utility for converting SPHERE waveform files
* to other common digital audio file formats
*
* Usage: sph2pipe [-f sph|wav|raw] [-t bsec:esec | -s bsamp:esamp]
* [-h hdrfile] [-c 1|2] [-p|-u|-a] infile [outfile]
*
* The NIST "SPHERE" file format for waveform data consists of a plain-text
* header that describes the file contents, followed by the raw (binary)
* sample data; the size of the sphere header is always a multiple of 1024
* bytes, and is always stated as an ASCII digit string in the second line
* of text (bytes 8-15 of the file); the description of content always
* includes the following elements, though not in any specified order:
* - sample rate
* - sample count
* - channel count
* - bytes per sample
* - byte order (when bytes per sample is > 1)
* - sample coding -- one of: mulaw|alaw|pcm (linear signed int), with
* an added qualifier when the sample data are compressed
* Other information may be contained in the header as well, but this has
* no effect on the conversion to other file formats.
*
* Apple/Macintosh and Intel/Microsoft systems typically support RIFF
* format for digital audio data, and users of these systems typically
* do not have tools that can use sphere-formatted files as input.
* `sph2pipe' will produce usable RIFF versions of sphere files so
* that the waveform data is accessible using common tools on these
* systems. It can also produce the Mac-specific AIFF file format,
* the AU format often used on Sun/sparc and Next systems, or raw
* (headerless) sample data.
*
* Input conditions:
* - input can be any valid sphere file, or any raw (headerless)
* sample data file when a suitable sphere header is provided
* separately, via the "-h hdrfile" option
* - input must be read from disk or cdrom, not from stdin
* - may be shorten compressed, or not
* - may be single- or two-channel
* - may be pcm or ulaw
* - if 2-byte pcm, may be either byte-order (HL/10 or LH/01)
* - may be any sample rate (typically 10, 11.025, 12.5, 16, 20, 22.1 KHz)
* - may be any size (from several KB to hundreds of MB)
*
* Output conditions:
* - output is written to stdout, unless an output file name is given
* - always uncompressed
* - formats: SPH,AU,WAV/RIFF,MAC/AIFF,RAW [-f sph/au/(wav|rif)/(mac|aif)/raw]
* - if two-channel, allow demux (output user-selected channel) [-c 1/2]
* - allow conversion to linear pcm [-p], alaw [-a] or mulaw [-u]
* - if writing pcm, byte order is set by output format or machine byte-order
* - allow selection (sec or samples) of start and end boundaries for output
*
* Overall method of operation:
* - determine native byte order of the machine we're running on
* - get user selections (from command line):
* -- input file name (and optional output file name)
* -- output file format (default="native" format of user's system)
* -- output channel (ignored for 1-ch input; default="both" for 2-ch)
* -- SPHERE header file (default=read SPHERE header from input file)
* -- force pcm or mular output (default=same as input)
* - read input sphere header for sample rate, etc.
* - create and output desired target file header, if any
* - loop over input data; for each buffer read from input:
* -- uncompress via "shorten extract" if necessary
* -- skip or seek past unwanted portions if necessary
* -- demux (discard one channel) if necessary
* -- convert to ulaw or to pcm if necessary
* -- invert byte order if necessary
* -- write to output
* - close input file and exit
*
* The program includes source code for "shorten-compressed" data extraction;
* the shorten source code is copyright 1991-1999, Anthony J. Robinson.
*/
/* VERSION information:
* This is version 2.4, intended to work on Wintel (MS Windows
* 95/98/NT), linux, solaris -- also works on MacOS X, but not
* intended for ealier Macintosh systems.
* Revision history:
* - v1.1 was called "sph_convert", worked on one file at a time and allowed
* output to a named file; as of v1.2, sph_convert became a very different
* application (including mac support), and sph2pipe branched off.
* - sph2pipe v1.2 added sphere-header output (not available in sph_convert)
* - sph2pipe v2.0 was a major re-organization of the code, to simplify the
* maintenance of the "separate-but-almost-equal" sph_convert utility
* - sph2pipe v2.1 fixed a subtle bug in handling two-channel data (the fix
* was also incorporated into sph_convert v2.0)
* - sph2pipe v2.2 added options for AU and AIFF output formats
* - sph2pipe v2.3 added "-s bsamp:esamp" and "-t bsec:esec" for selecting
* ranges and the "-h hdrfile" option for using "stand-off" sphere headers
* with raw sample data as input.
* - sph2pipe v2.4 added alaw support (only for non-shortened data, because
* shorten does not support alaw), and fixed a bug in the logic involving
* the use of "-h hdrfile".
*/
#define _SPH_CONVERT_MAIN_
#include "sph_convert.h"
#include "ulaw.h"
#include <getopt.h>
static double bgnsec, endsec;
static int bgnsamp, endsamp;
static char *hdrfile;
int main( int argc, char **argv )
{
int ret, n;
char *usage =
"Usage: sph2pipe [-h hdr] [-t|-s b:e] [-c 1|2] [-p|-u|-a] [-f typ] infile [outfile]\n\n\
default conditions (for 'sph2pipe infile'):\n\
* input file contains sphere header\n\
* output full duration of input file\n\
* output all channels from input file\n\
* output same sample coding as input file\n\
* output format is WAV on Wintel machines, SPH elsewhere\n\
* output is written to stdout\n\n\
optional controls (items bracketed separately above can be combined):\n\
-h hdr -- treat infile as headerless, get sphere info from file 'hdr'\n\
-t b:e -- output portion between b and e sec (floating point)\n\
-s b:e -- output portion between b and e samples (integer)\n\
-c 1 -- only output first channel\n\
-c 2 -- only output second channel\n\
-p -- force conversion to 16-bit linear pcm\n\
-u -- force conversion to 8-bit ulaw\n\
-a -- force conversion to 8-bit alaw\n\
-f typ -- select alternate output header format 'typ'\n\
five types: sph, raw, au, rif(wav), aif(mac)\n";
/* find out what the native byte order is:
*/
short_order.i2 = 1;
nativorder = ( short_order.ch[0] ) ? "01" : "10";
#ifdef MSDOS
def_outheader = "RIFF";
#else
def_outheader = "SPH";
#endif
/* command line options will decide the output conditions
*/
if ( getUserOpts( argc, argv )) {
fputs( usage, stderr );
exit(1);
}
/* make the data buffers
*/
if (( outbuf = (char *) malloc( STD_BUF_SIZE*2 )) == NULL ||
( inpbuf = (char *) malloc( STD_BUF_SIZE*2 )) == NULL ) {
fprintf( stderr, "Not enough memory for %d byte buffer\n",
STD_BUF_SIZE*4 );
exit(1);
}
/* When adapting to handle multiple files in one run, the following
* function call would need to be placed into an appropriate loop or
* directory-tree-walk function (and output filename handling would
* most likely need to be added):
*/
ret = doConversion( inpname, outname );
exit(ret);
}
/* end of main() */
int getUserOpts( int ac, char **av )
{
int i, nfn;
char *cln;
extern char *optarg;
extern int optind;
/* set initial default values for command-line controls
*/
hdrfile = NULL;
debug = 0;
endsec = bgnsec = 0;
endsamp = bgnsamp = 0;
typeout = 0; /* will be interpreted as "same as input sample type" */
chanout = 2; /* will be interpreted as "same as input channel count" */
outheader = def_outheader; /* OS dependent (see sph_convert.h) */
while (( i = getopt( ac, av, "daupf:c:t:s:h:" )) != EOF )
switch ( i )
{
case 'd':
debug = 1;
break;
case 'p': /* force pcm output, regardless of input sample type */
typeout = PCM;
break;
case 'u': /* force ulaw output, regardless of input sample type */
typeout = ULAW;
break;
case 'a': /* force alaw output, regardless of input sample type */
typeout = ALAW;
break;
case 'c': /* output just one channel, if input is two-channel */
chanout = ( *optarg == '1' ) ? 0 : ( *optarg == '2' ) ? 1 : -1;
break;
case 'h':
hdrfile = strdup( optarg );
break;
case 'f': /* force a particular output format */
if ( strncasecmp( optarg, "RIF", 3 ) == 0 ||
strncasecmp( optarg, "WAV", 3 ) == 0 )
outheader = "RIFF";
else if ( strncasecmp( optarg, "RAW", 3 ) == 0 )
outheader = "RAW";
else if ( strncasecmp( optarg, "SPH", 3 ) == 0 )
outheader = "SPH";
else if ( strncasecmp( optarg, "AU", 2 ) == 0 )
outheader = "AU";
else if ( strncasecmp( optarg, "AIF", 3 ) == 0 ||
strncasecmp( optarg, "MAC", 3 ) == 0 )
outheader = "AIF";
else
outheader = NULL;
break;
case 't': /* output only a portion of the file's timeline */
if (( cln = index( optarg, ':' )) == NULL ) {
fprintf( stderr, "invalid arg for -t -- missing ':'\n" );
return 1;
}
if ( cln > optarg ) { /* arg did not start with colon */
*cln = '\0';
if ( sscanf( optarg, "%lf", &bgnsec ) != 1 ) {
fprintf( stderr, "invalid first arg for -t\n" );
return 1;
}
}
cln++;
if ( *cln != '\0' ) { /* arg did not end with colon */
if ( sscanf( cln, "%lf", &endsec ) != 1 ) {
fprintf( stderr, "invalid second arg for -t\n" );
return 1;
}
}
if ( bgnsec > 0 && endsec > 0 && bgnsec >= endsec ) {
fprintf( stderr, "bgnsec %lf >= endsec %lf\n",
bgnsec, endsec );
return 1;
}
break;
case 's': /* output only a portion of the file's samples */
if (( cln = index( optarg, ':' )) == NULL ) {
fprintf( stderr, "invalid arg for -s -- missing ':'\n" );
return 1;
}
if ( cln > optarg ) { /* arg did not start with colon */
*cln = '\0';
if ( sscanf( optarg, "%d", &bgnsamp ) != 1 ) {
fprintf( stderr, "invalid first arg for -s\n" );
return 1;
}
}
cln++;
if ( *cln != '\0' ) { /* arg did not end with colon */
if ( sscanf( cln, "%d", &endsamp ) != 1 ) {
fprintf( stderr, "invalid second arg for -s\n" );
return 1;
}
}
if ( bgnsamp > 0 && endsamp > 0 && bgnsamp >= endsamp ) {
fprintf( stderr, "bgnsamp %d >= endsamp %d\n",
bgnsamp, endsamp );
return 1;
}
break;
default:
return 1;
}
/* A successful command line must provide one or two file names (input file,
* output file), and recognized values for "-c" and/or "-f" if these are used
*/
nfn = ac - optind;
if (( nfn + 1 )/2 != 1 || outheader == NULL || chanout < 0 )
return 1;
/* Output byte order will be HL for aif and au files, LH for riff files,
* native order otherwise
*/
outorder = ( !strcmp( outheader, "AU" ) || !strcmp( outheader, "AIF" )) ? "10" :
( !strcmp( outheader, "RIFF" )) ? "01" : nativorder;
/* Output sample coding will be PCM for aif files (aif does not support ULAW)
*/
if ( !strcmp( outheader, "AIF" ))
typeout = PCM;
if ( debug ) {
fprintf( stderr, "command-line params: sizeout=%d, typeout=%d, outorder=%s, outheader=%s,\n",
sizeout, typeout, outorder, outheader );
fprintf( stderr, " bgnsamp=%d, bgnsec=%f, endsamp=%d, endsec=%f, chanout=%d\n",
bgnsamp, bgnsec, endsamp, endsec, chanout );
}
inpname = strdup( av[optind] );
outname = ( nfn == 2 ) ? strdup( av[optind+1] ) : NULL;
return 0;
}
int doConversion( char *inpname, char *outname )
{
int ret;
if (( fpin = fopen( inpname, "rb" )) == NULL ) {
fprintf( stderr, "Unable to open %s as input\n", inpname );
return 1;
}
if ( outname == NULL ) {
fpout = stdout;
outname = "stdout";
#ifdef MSDOS
setmode(fileno(fpout), O_BINARY);
#endif
}
else if (( fpout = fopen( outname, "wb" )) == NULL ) {
fprintf( stderr, "Unable to open %s as output\n", outname );
return 1;
}
/* input file header will set the input conditions (and some global variables)
*/
if ( readSphHeader( hdrfile )) {
fprintf( stderr, "Input file %s is not a valid SPHERE file\n",
inpname );
return 1;
}
if ( bgnsec > totalsec || bgnsamp > sampcount ) {
fprintf( stderr, "start point > length of %s\n", inpname );
return 1;
}
startout = ( bgnsamp ) ? bgnsamp : (int)( bgnsec * samprate );
endout = ( endsamp > sampcount ||
endsec >= totalsec ||
endsamp + endsec == 0 ) ? sampcount :
( endsamp > 0 ) ? endsamp : (int)( endsec * samprate );
/*
fprintf( stderr, "startout=%d (bgnsec=%f) endout=%d (endsec=%f)\n",
startout, bgnsec, endout, endsec );
*/
if ( typeout == 0 ) /* if command line didn't say... */
typeout = samptype; /* keep samptype same as input */
if ( chancount == 1 ) /* if input is single-channel... */
chanout = chancount; /* "-c" option doesn't matter */
if ( endout < 0 || endout > sampcount )
endout = sampcount;
if ( startout > 0 || endout < sampcount )
sampcount = endout - startout;
sizeout = typeout & 3; /* yields 1 for ulaw/alaw, 2 for pcm */
if ( debug ) {
fprintf( stderr, "control params: sizeout=%d, typeout=%d, outorder=%s, outheader=%s, chanout=%d,\n",
sizeout, typeout, outorder, outheader, chanout );
fprintf( stderr, " bgnsamp=%d, bgnsec=%f, endsamp=%d, endsec=%f, startout=%d, endout=%d, sampcount=%d\n",
bgnsamp, bgnsec, endsamp, endsec, startout, endout, sampcount );
}
/* now that we know what's coming in and going out, write the
* appropriate output header, if any
*/
if ( !strcmp( outheader, "RIFF" ))
writeRIFFHeader();
else if ( !strcmp( outheader, "AIF" ))
writeAIFFHeader();
else if ( !strcmp( outheader, "AU" ))
writeAUHeader();
else if ( !strcmp( outheader, "SPH" ))
writeSphHeader();
/* now pass the data through */
if ( doshorten )
ret = shortenXtract();
else
ret = copySamples();
if ( ret )
fprintf( stderr, "conversion failed for %s\n", inpname );
fclose( fpin );
fclose( fpout );
return ret;
}
/*************************************************************
* pcm2ulaw
*------------------------------------------------------------
* Copied verbatim from Tony Robinson's "ulaw.c" (which in turn
* was copied from Craig Reese)
*/
/*
** This routine converts from linear to ulaw.
**
** Craig Reese: IDA/Supercomputing Research Center
** Joe Campbell: Department of Defense
** 29 September 1989
**
** References:
** 1) CCITT Recommendation G.711 (very difficult to follow)
** 2) "A New Digital Technique for Implementation of Any
** Continuous PCM Companding Law," Villeret, Michel,
** et al. 1973 IEEE Int. Conf. on Communications, Vol 1,
** 1973, pg. 11.12-11.17
** 3) MIL-STD-188-113,"Interoperability and Performance Standards
** for Analog-to_Digital Conversion Techniques,"
** 17 February 1987
**
** Input: Signed 16 bit linear sample
** Output: 8 bit ulaw sample
*/
#define ZEROTRAP /* turn on the trap as per the MIL-STD */
#undef ZEROTRAP
#define BIAS 0x84 /* define the add-in bias for 16 bit samples */
#define CLIP 32635
uchar pcm2ulaw( short int sample )
{
static int exp_lut[256] = {0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,
4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7};
int sign, exponent, mantissa;
uchar ulawbyte;
/* Get the sample into sign-magnitude. */
sign = (sample >> 8) & 0x80; /* set aside the sign */
if(sign != 0) sample = -sample; /* get magnitude */
if(sample > CLIP) sample = CLIP; /* clip the magnitude */
/* Convert from 16 bit linear to ulaw. */
sample = sample + BIAS;
exponent = exp_lut[( sample >> 7 ) & 0xFF];
mantissa = (sample >> (exponent + 3)) & 0x0F;
ulawbyte = ~(sign | (exponent << 4) | mantissa);
#ifdef ZEROTRAP
if (ulawbyte == 0) ulawbyte = 0x02; /* optional CCITT trap */
#endif
return(ulawbyte);
}
/************************************************************
* pcm2alaw
*-----------------------------------------------------------
* Adapted from "st_13linear2alaw()" function in SoX, as
* found in "g711.c"
*/
#define SEG_SHIFT (4) /* Left shift for segment number */
#define QUANT_MASK (0xf) /* Quantization field mask */
uchar pcm2alaw( short int pcmval )
{
short int mask, seg;
uchar aval;
static short int seg_end[8] = { 0x1F, 0x3F, 0x7F, 0xFF,
0x1FF,0x3FF,0x7FF,0xFFF };
pcmval = pcmval >> 3; /* shift down to 13 bits */
if ( pcmval >= 0 )
mask = 0xd5;
else {
mask = 0x55;
pcmval = -pcmval - 1;
}
for ( seg=0; seg<8; seg++ ) {
if ( pcmval <= seg_end[seg] )
break;
}
if ( seg == 8 )
return (unsigned char) (0x7F ^ mask);
else {
aval = (unsigned char) seg << SEG_SHIFT;
aval |= ( seg < 2 ) ? (pcmval >> 1) & QUANT_MASK : (pcmval >> seg) & QUANT_MASK;
return (aval ^ mask);
}
}
int copySamples( void )
{
int i, nb, ns, sampsdone;
short int *sptr, *cnvptr, s;
uchar *cptr, (*pcm2xptr)( short int );
char *wptr;
if ( startout > 0 )
fseek( fpin, startout * sampsize * chancount, SEEK_CUR );
sampsdone = 0;
while (( nb = fread( inpbuf, 1, STD_BUF_SIZE, fpin )) > 0 &&
sampsdone < sampcount )
{
ns = nb / ( chancount * sampsize );
if (( sampsdone + ns ) > sampcount ) {
ns = sampcount - sampsdone;
nb = ns * chancount * sampsize;
}
sampsdone += ns;
if ( chancount > chanout ) { /* input chancount==2, chanout=0 or 1 */
demux( nb );
nb /= 2;
}
wptr = inpbuf;
if ( sampsize < sizeout ) { /* convert ulaw or alaw to pcm */
cptr = inpbuf;
sptr = (short int *) outbuf;
cnvptr = ( samptype == ALAW ) ? alaw2pcm : ulaw2pcm;
for ( i=0; i<nb; i++ )
*sptr++ = cnvptr[*cptr++];
nb *= 2;
if ( strcmp( nativorder, outorder )) /* if output filetype needs */
swab( outbuf, inpbuf, nb ); /* it, do byte swapping too */
else
wptr = outbuf;
}
else if ( sampsize > sizeout ) { /* convert pcm to ulaw or alaw */
if ( strcmp( inporder, nativorder )) { /* if inp. filetype needs */
swab( inpbuf, outbuf, nb ); /* it, do byte swap first */
sptr = (short int *) outbuf;
cptr = inpbuf;
} else {
wptr = cptr = outbuf;
sptr = (short int *) inpbuf;
}
if ( typeout == ALAW )
pcm2xptr = pcm2alaw;
else
pcm2xptr = pcm2ulaw;
for ( i=0; i<nb; i+=2 )
*cptr++ = (*pcm2xptr)( *sptr++ );
nb /= 2;
}
else if ( samptype == ALAW && typeout == ULAW ) { /* convert alaw to ulaw */
cptr = inpbuf;
for ( i=0; i<nb; i++ ) {
s = alaw2pcm[*cptr];
*cptr++ = pcm2ulaw( s );
}
}
else if ( samptype == ULAW && typeout == ALAW ) { /* convert ulaw to alaw */
cptr = inpbuf;
for ( i=0; i<nb; i++ ) {
s = ulaw2pcm[*cptr];
*cptr++ = pcm2alaw( s );
}
}
else if ( samptype == 2 && strcmp( inporder, outorder )) {
swab( inpbuf, outbuf, nb );
wptr = outbuf;
}
if ( fwrite( wptr, 1, nb, fpout ) != nb ) {
fprintf( stderr, "Failed while writing sample data to %s\n",
outname );
exit( 1 );
}
}
if ( sampsdone != sampcount )
fprintf( stderr, "Warning: %d samples written, %d samples expected\n",
sampsdone, sampcount );
return( sampsdone != sampcount );
}
void demux( int ns )
{
int i;
short int *sptr, *sptr2;
uchar *cptr, *cptr2;
/* To demultiplex, simply move the samples of the selected channel
* so that they are adjacent starting at offset 0 of inpbuf; this
* overwrites the unselected channel data.
*/
if ( sampsize == 2 ) {
ns /= 2;
i = chanout;
sptr = (short int *) inpbuf;
sptr2 = sptr + chanout;
if ( chanout == 0 ) {
i = 2;
sptr++;
sptr2 += 2;
}
for ( ; i<ns; i+=2 ) {
*sptr++ = *sptr2;
sptr2 += 2;
}
} else { /* sampsize == 1 */
i = chanout;
cptr = inpbuf;
cptr2 = cptr + chanout;
if ( chanout == 0 ) {
i = 2;
cptr++;
cptr2 += 2;
}
for ( ; i<ns; i+=2 ) {
*cptr++ = *cptr2;
cptr2 += 2;
}
}
}