-
Notifications
You must be signed in to change notification settings - Fork 0
/
latency.c
655 lines (650 loc) · 25.1 KB
/
latency.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
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
/*
* Latency test program
*
* Author: Jaroslav Kysela <[email protected]>
*
* Author of bandpass filter sweep effect:
* Maarten de Boer <[email protected]>
*
* This small demo program can be used for measuring latency between
* capture and playback. This latency is measured from driver (diff when
* playback and capture was started). Scheduler is set to SCHED_RR.
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/* Compile with gcc -o latency latency.c -lasound -lm */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sched.h>
#include <errno.h>
#include <getopt.h>
#include <alsa/asoundlib.h>
#include <sys/time.h>
#include <math.h>
char *pdevice = "hw:0,0";
char *cdevice = "hw:0,0";
snd_pcm_format_t format = SND_PCM_FORMAT_S16_LE;
int rate = 22050;
int channels = 2;
int buffer_size = 0; /* auto */
int period_size = 0; /* auto */
int latency_min = 32; /* in frames / 2 */
int latency_max = 2048; /* in frames / 2 */
int loop_sec = 30; /* seconds */
int block = 0; /* block mode */
int use_poll = 0;
int resample = 1;
unsigned long loop_limit;
snd_output_t *output = NULL;
int setparams_stream(snd_pcm_t *handle,
snd_pcm_hw_params_t *params,
const char *id)
{
int err;
unsigned int rrate;
err = snd_pcm_hw_params_any(handle, params);
if (err < 0) {
printf("Broken configuration for %s PCM: no configurations available: %s\n", snd_strerror(err), id);
return err;
}
err = snd_pcm_hw_params_set_rate_resample(handle, params, resample);
if (err < 0) {
printf("Resample setup failed for %s (val %i): %s\n", id, resample, snd_strerror(err));
return err;
}
err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
if (err < 0) {
printf("Access type not available for %s: %s\n", id, snd_strerror(err));
return err;
}
err = snd_pcm_hw_params_set_format(handle, params, format);
if (err < 0) {
printf("Sample format not available for %s: %s\n", id, snd_strerror(err));
return err;
}
err = snd_pcm_hw_params_set_channels(handle, params, channels);
if (err < 0) {
printf("Channels count (%i) not available for %s: %s\n", channels, id, snd_strerror(err));
return err;
}
rrate = rate;
err = snd_pcm_hw_params_set_rate_near(handle, params, &rrate, 0);
if (err < 0) {
printf("Rate %iHz not available for %s: %s\n", rate, id, snd_strerror(err));
return err;
}
if ((int)rrate != rate) {
printf("Rate doesn't match (requested %iHz, get %iHz)\n", rate, err);
return -EINVAL;
}
return 0;
}
int setparams_bufsize(snd_pcm_t *handle,
snd_pcm_hw_params_t *params,
snd_pcm_hw_params_t *tparams,
snd_pcm_uframes_t bufsize,
const char *id)
{
int err;
snd_pcm_uframes_t periodsize;
snd_pcm_hw_params_copy(params, tparams);
periodsize = bufsize * 2;
err = snd_pcm_hw_params_set_buffer_size_near(handle, params, &periodsize);
if (err < 0) {
printf("Unable to set buffer size %li for %s: %s\n", bufsize * 2, id, snd_strerror(err));
return err;
}
if (period_size > 0)
periodsize = period_size;
else
periodsize /= 2;
err = snd_pcm_hw_params_set_period_size_near(handle, params, &periodsize, 0);
if (err < 0) {
printf("Unable to set period size %li for %s: %s\n", periodsize, id, snd_strerror(err));
return err;
}
return 0;
}
int setparams_set(snd_pcm_t *handle,
snd_pcm_hw_params_t *params,
snd_pcm_sw_params_t *swparams,
const char *id)
{
int err;
snd_pcm_uframes_t val;
err = snd_pcm_hw_params(handle, params);
if (err < 0) {
printf("Unable to set hw params for %s: %s\n", id, snd_strerror(err));
return err;
}
err = snd_pcm_sw_params_current(handle, swparams);
if (err < 0) {
printf("Unable to determine current swparams for %s: %s\n", id, snd_strerror(err));
return err;
}
err = snd_pcm_sw_params_set_start_threshold(handle, swparams, 0x7fffffff);
if (err < 0) {
printf("Unable to set start threshold mode for %s: %s\n", id, snd_strerror(err));
return err;
}
if (!block)
val = 4;
else
snd_pcm_hw_params_get_period_size(params, &val, NULL);
err = snd_pcm_sw_params_set_avail_min(handle, swparams, val);
if (err < 0) {
printf("Unable to set avail min for %s: %s\n", id, snd_strerror(err));
return err;
}
err = snd_pcm_sw_params(handle, swparams);
if (err < 0) {
printf("Unable to set sw params for %s: %s\n", id, snd_strerror(err));
return err;
}
return 0;
}
int setparams(snd_pcm_t *phandle, snd_pcm_t *chandle, int *bufsize)
{
int err, last_bufsize = *bufsize;
snd_pcm_hw_params_t *pt_params, *ct_params; /* templates with rate, format and channels */
snd_pcm_hw_params_t *p_params, *c_params;
snd_pcm_sw_params_t *p_swparams, *c_swparams;
snd_pcm_uframes_t p_size, c_size, p_psize, c_psize;
unsigned int p_time, c_time;
unsigned int val;
snd_pcm_hw_params_alloca(&p_params);
snd_pcm_hw_params_alloca(&c_params);
snd_pcm_hw_params_alloca(&pt_params);
snd_pcm_hw_params_alloca(&ct_params);
snd_pcm_sw_params_alloca(&p_swparams);
snd_pcm_sw_params_alloca(&c_swparams);
if ((err = setparams_stream(phandle, pt_params, "playback")) < 0) {
printf("Unable to set parameters for playback stream: %s\n", snd_strerror(err));
exit(0);
}
if ((err = setparams_stream(chandle, ct_params, "capture")) < 0) {
printf("Unable to set parameters for playback stream: %s\n", snd_strerror(err));
exit(0);
}
if (buffer_size > 0) {
*bufsize = buffer_size;
goto __set_it;
}
__again:
if (buffer_size > 0)
return -1;
if (last_bufsize == *bufsize)
*bufsize += 4;
last_bufsize = *bufsize;
if (*bufsize > latency_max)
return -1;
__set_it:
if ((err = setparams_bufsize(phandle, p_params, pt_params, *bufsize, "playback")) < 0) {
printf("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err));
exit(0);
}
if ((err = setparams_bufsize(chandle, c_params, ct_params, *bufsize, "capture")) < 0) {
printf("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err));
exit(0);
}
snd_pcm_hw_params_get_period_size(p_params, &p_psize, NULL);
if (p_psize > (unsigned int)*bufsize)
*bufsize = p_psize;
snd_pcm_hw_params_get_period_size(c_params, &c_psize, NULL);
if (c_psize > (unsigned int)*bufsize)
*bufsize = c_psize;
snd_pcm_hw_params_get_period_time(p_params, &p_time, NULL);
snd_pcm_hw_params_get_period_time(c_params, &c_time, NULL);
if (p_time != c_time)
goto __again;
snd_pcm_hw_params_get_buffer_size(p_params, &p_size);
if (p_psize * 2 < p_size) {
snd_pcm_hw_params_get_periods_min(p_params, &val, NULL);
if (val > 2) {
printf("playback device does not support 2 periods per buffer\n");
exit(0);
}
goto __again;
}
snd_pcm_hw_params_get_buffer_size(c_params, &c_size);
if (c_psize * 2 < c_size) {
snd_pcm_hw_params_get_periods_min(c_params, &val, NULL);
if (val > 2 ) {
printf("capture device does not support 2 periods per buffer\n");
exit(0);
}
goto __again;
}
if ((err = setparams_set(phandle, p_params, p_swparams, "playback")) < 0) {
printf("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err));
exit(0);
}
if ((err = setparams_set(chandle, c_params, c_swparams, "capture")) < 0) {
printf("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err));
exit(0);
}
if ((err = snd_pcm_prepare(phandle)) < 0) {
printf("Prepare error: %s\n", snd_strerror(err));
exit(0);
}
snd_pcm_dump(phandle, output);
snd_pcm_dump(chandle, output);
fflush(stdout);
return 0;
}
void showstat(snd_pcm_t *handle, size_t frames)
{
int err;
snd_pcm_status_t *status;
snd_pcm_status_alloca(&status);
if ((err = snd_pcm_status(handle, status)) < 0) {
printf("Stream status error: %s\n", snd_strerror(err));
exit(0);
}
printf("*** frames = %li ***\n", (long)frames);
snd_pcm_status_dump(status, output);
}
void showlatency(size_t latency)
{
double d;
latency *= 2;
d = (double)latency / (double)rate;
printf("Trying latency %li frames, %.3fus, %.6fms (%.4fHz)\n", (long)latency, d * 1000000, d * 1000, (double)1 / d);
}
void showinmax(size_t in_max)
{
double d;
printf("Maximum read: %li frames\n", (long)in_max);
d = (double)in_max / (double)rate;
printf("Maximum read latency: %.3fus, %.6fms (%.4fHz)\n", d * 1000000, d * 1000, (double)1 / d);
}
void gettimestamp(snd_pcm_t *handle, snd_timestamp_t *timestamp)
{
int err;
snd_pcm_status_t *status;
snd_pcm_status_alloca(&status);
if ((err = snd_pcm_status(handle, status)) < 0) {
printf("Stream status error: %s\n", snd_strerror(err));
exit(0);
}
snd_pcm_status_get_trigger_tstamp(status, timestamp);
}
void setscheduler(void)
{
struct sched_param sched_param;
if (sched_getparam(0, &sched_param) < 0) {
printf("Scheduler getparam failed...\n");
return;
}
sched_param.sched_priority = sched_get_priority_max(SCHED_RR);
if (!sched_setscheduler(0, SCHED_RR, &sched_param)) {
printf("Scheduler set to Round Robin with priority %i...\n", sched_param.sched_priority);
fflush(stdout);
return;
}
printf("!!!Scheduler set to Round Robin with priority %i FAILED!!!\n", sched_param.sched_priority);
}
long timediff(snd_timestamp_t t1, snd_timestamp_t t2)
{
signed long l;
t1.tv_sec -= t2.tv_sec;
l = (signed long) t1.tv_usec - (signed long) t2.tv_usec;
if (l < 0) {
t1.tv_sec--;
l = 1000000 + l;
l %= 1000000;
}
return (t1.tv_sec * 1000000) + l;
}
long readbuf(snd_pcm_t *handle, char *buf, long len, size_t *frames, size_t *max)
{
long r;
if (!block) {
do {
r = snd_pcm_readi(handle, buf, len);
} while (r == -EAGAIN);
if (r > 0) {
*frames += r;
if ((long)*max < r)
*max = r;
}
// printf("read = %li\n", r);
} else {
int frame_bytes = (snd_pcm_format_width(format) / 8) * channels;
do {
r = snd_pcm_readi(handle, buf, len);
if (r > 0) {
buf += r * frame_bytes;
len -= r;
*frames += r;
if ((long)*max < r)
*max = r;
}
// printf("r = %li, len = %li\n", r, len);
} while (r >= 1 && len > 0);
}
// showstat(handle, 0);
return r;
}
long writebuf(snd_pcm_t *handle, char *buf, long len, size_t *frames)
{
long r;
while (len > 0) {
r = snd_pcm_writei(handle, buf, len);
if (r == -EAGAIN)
continue;
// printf("write = %li\n", r);
if (r < 0)
return r;
// showstat(handle, 0);
buf += r * 4;
len -= r;
*frames += r;
}
return 0;
}
#define FILTERSWEEP_LFO_CENTER 2000.
#define FILTERSWEEP_LFO_DEPTH 1800.
#define FILTERSWEEP_LFO_FREQ 0.2
#define FILTER_BANDWIDTH 50
/* filter the sweep variables */
float lfo,dlfo,fs,fc,BW,C,D,a0,a1,a2,b1,b2,*x[3],*y[3];
void applyeffect(char* buffer,int r)
{
short* samples = (short*) buffer;
int i;
for (i=0;i<r;i++)
{
int chn;
fc = sin(lfo)*FILTERSWEEP_LFO_DEPTH+FILTERSWEEP_LFO_CENTER;
lfo += dlfo;
if (lfo>2.*M_PI) lfo -= 2.*M_PI;
C = 1./tan(M_PI*BW/fs);
D = 2.*cos(2*M_PI*fc/fs);
a0 = 1./(1.+C);
a1 = 0;
a2 = -a0;
b1 = -C*D*a0;
b2 = (C-1)*a0;
for (chn=0;chn<channels;chn++)
{
x[chn][2] = x[chn][1];
x[chn][1] = x[chn][0];
y[chn][2] = y[chn][1];
y[chn][1] = y[chn][0];
x[chn][0] = samples[i*channels+chn];
y[chn][0] = a0*x[chn][0] + a1*x[chn][1] + a2*x[chn][2]
- b1*y[chn][1] - b2*y[chn][2];
samples[i*channels+chn] = y[chn][0];
}
}
}
void help(void)
{
int k;
printf(
"Usage: latency [OPTION]... [FILE]...\n"
"-h,--help help\n"
"-P,--pdevice playback device\n"
"-C,--cdevice capture device\n"
"-m,--min minimum latency in frames\n"
"-M,--max maximum latency in frames\n"
"-F,--frames frames to transfer\n"
"-f,--format sample format\n"
"-c,--channels channels\n"
"-r,--rate rate\n"
"-B,--buffer buffer size in frames\n"
"-E,--period period size in frames\n"
"-s,--seconds duration of test in seconds\n"
"-b,--block block mode\n"
"-p,--poll use poll (wait for event - reduces CPU usage)\n"
"-e,--effect apply an effect (bandpass filter sweep)\n"
);
printf("Recognized sample formats are:");
for (k = 0; k < SND_PCM_FORMAT_LAST; ++k) {
const char *s = snd_pcm_format_name(k);
if (s)
printf(" %s", s);
}
printf("\n\n");
printf(
"Tip #1 (usable latency with large periods, non-blocking mode, good CPU usage,\n"
" superb xrun prevention):\n"
" latency -m 8192 -M 8192 -t 1 -p\n"
"Tip #2 (superb latency, non-blocking mode, but heavy CPU usage):\n"
" latency -m 128 -M 128\n"
);
}
int main(int argc, char *argv[])
{
struct option long_option[] =
{
{"help", 0, NULL, 'h'},
{"pdevice", 1, NULL, 'P'},
{"cdevice", 1, NULL, 'C'},
{"min", 1, NULL, 'm'},
{"max", 1, NULL, 'M'},
{"frames", 1, NULL, 'F'},
{"format", 1, NULL, 'f'},
{"channels", 1, NULL, 'c'},
{"rate", 1, NULL, 'r'},
{"buffer", 1, NULL, 'B'},
{"period", 1, NULL, 'E'},
{"seconds", 1, NULL, 's'},
{"block", 0, NULL, 'b'},
{"poll", 0, NULL, 'p'},
{"effect", 0, NULL, 'e'},
{NULL, 0, NULL, 0},
};
snd_pcm_t *phandle, *chandle;
char *buffer;
int err, latency, morehelp;
int ok;
snd_timestamp_t p_tstamp, c_tstamp;
ssize_t r;
size_t frames_in, frames_out, in_max;
int effect = 0;
morehelp = 0;
while (1) {
int c;
if ((c = getopt_long(argc, argv, "hP:C:m:M:F:f:c:r:B:E:s:bpen", long_option, NULL)) < 0)
break;
switch (c) {
case 'h':
morehelp++;
break;
case 'P':
pdevice = strdup(optarg);
break;
case 'C':
cdevice = strdup(optarg);
break;
case 'm':
err = atoi(optarg) / 2;
latency_min = err >= 4 ? err : 4;
if (latency_max < latency_min)
latency_max = latency_min;
break;
case 'M':
err = atoi(optarg) / 2;
latency_max = latency_min > err ? latency_min : err;
break;
case 'f':
format = snd_pcm_format_value(optarg);
if (format == SND_PCM_FORMAT_UNKNOWN) {
printf("Unknown format, setting to default S16_LE\n");
format = SND_PCM_FORMAT_S16_LE;
}
break;
case 'c':
err = atoi(optarg);
channels = err >= 1 && err < 1024 ? err : 1;
break;
case 'r':
err = atoi(optarg);
rate = err >= 4000 && err < 200000 ? err : 44100;
break;
case 'B':
err = atoi(optarg);
buffer_size = err >= 32 && err < 200000 ? err : 0;
break;
case 'E':
err = atoi(optarg);
period_size = err >= 32 && err < 200000 ? err : 0;
break;
case 's':
err = atoi(optarg);
loop_sec = err >= 1 && err <= 100000 ? err : 30;
break;
case 'b':
block = 1;
break;
case 'p':
use_poll = 1;
break;
case 'e':
effect = 1;
break;
case 'n':
resample = 0;
break;
}
}
if (morehelp) {
help();
return 0;
}
err = snd_output_stdio_attach(&output, stdout, 0);
if (err < 0) {
printf("Output failed: %s\n", snd_strerror(err));
return 0;
}
loop_limit = loop_sec * rate;
latency = latency_min - 4;
buffer = malloc((latency_max * snd_pcm_format_width(format) / 8) * 2);
setscheduler();
printf("Playback device is %s\n", pdevice);
printf("Capture device is %s\n", cdevice);
printf("Parameters are %iHz, %s, %i channels, %s mode\n", rate, snd_pcm_format_name(format), channels, block ? "blocking" : "non-blocking");
printf("Poll mode: %s\n", use_poll ? "yes" : "no");
printf("Loop limit is %li frames, minimum latency = %i, maximum latency = %i\n", loop_limit, latency_min * 2, latency_max * 2);
if ((err = snd_pcm_open(&phandle, pdevice, SND_PCM_STREAM_PLAYBACK, block ? 0 : SND_PCM_NONBLOCK)) < 0) {
printf("Playback open error: %s\n", snd_strerror(err));
return 0;
}
if ((err = snd_pcm_open(&chandle, cdevice, SND_PCM_STREAM_CAPTURE, block ? 0 : SND_PCM_NONBLOCK)) < 0) {
printf("Record open error: %s\n", snd_strerror(err));
return 0;
}
/* initialize the filter sweep variables */
if (effect) {
fs = (float) rate;
BW = FILTER_BANDWIDTH;
lfo = 0;
dlfo = 2.*M_PI*FILTERSWEEP_LFO_FREQ/fs;
x[0] = (float*) malloc(channels*sizeof(float));
x[1] = (float*) malloc(channels*sizeof(float));
x[2] = (float*) malloc(channels*sizeof(float));
y[0] = (float*) malloc(channels*sizeof(float));
y[1] = (float*) malloc(channels*sizeof(float));
y[2] = (float*) malloc(channels*sizeof(float));
}
while (1) {
frames_in = frames_out = 0;
if (setparams(phandle, chandle, &latency) < 0)
break;
showlatency(latency);
if ((err = snd_pcm_link(chandle, phandle)) < 0) {
printf("Streams link error: %s\n", snd_strerror(err));
exit(0);
}
if (snd_pcm_format_set_silence(format, buffer, latency*channels) < 0) {
fprintf(stderr, "silence error\n");
break;
}
if (writebuf(phandle, buffer, latency, &frames_out) < 0) {
fprintf(stderr, "write error\n");
break;
}
if (writebuf(phandle, buffer, latency, &frames_out) < 0) {
fprintf(stderr, "write error\n");
break;
}
if ((err = snd_pcm_start(chandle)) < 0) {
printf("Go error: %s\n", snd_strerror(err));
exit(0);
}
gettimestamp(phandle, &p_tstamp);
gettimestamp(chandle, &c_tstamp);
#if 0
printf("Playback:\n");
showstat(phandle, frames_out);
printf("Capture:\n");
showstat(chandle, frames_in);
#endif
ok = 1;
in_max = 0;
while (ok && frames_in < loop_limit) {
if (use_poll) {
/* use poll to wait for next event */
snd_pcm_wait(chandle, 1000);
}
if ((r = readbuf(chandle, buffer, latency, &frames_in, &in_max)) < 0)
ok = 0;
else {
if (effect)
applyeffect(buffer,r);
if (writebuf(phandle, buffer, r, &frames_out) < 0)
ok = 0;
}
}
if (ok)
printf("Success\n");
else
printf("Failure\n");
printf("Playback:\n");
showstat(phandle, frames_out);
printf("Capture:\n");
showstat(chandle, frames_in);
showinmax(in_max);
if (p_tstamp.tv_sec == p_tstamp.tv_sec &&
p_tstamp.tv_usec == c_tstamp.tv_usec)
printf("Hardware sync\n");
snd_pcm_drop(chandle);
snd_pcm_nonblock(phandle, 0);
snd_pcm_drain(phandle);
snd_pcm_nonblock(phandle, !block ? 1 : 0);
if (ok) {
#if 1
printf("Playback time = %li.%i, Record time = %li.%i, diff = %li\n",
p_tstamp.tv_sec,
(int)p_tstamp.tv_usec,
c_tstamp.tv_sec,
(int)c_tstamp.tv_usec,
timediff(p_tstamp, c_tstamp));
#endif
break;
}
snd_pcm_unlink(chandle);
snd_pcm_hw_free(phandle);
snd_pcm_hw_free(chandle);
}
snd_pcm_close(phandle);
snd_pcm_close(chandle);
return 0;
}