+/*
+ * Latency test program
+ *
+ * Author: Jaroslav Kysela <perex@suse.cz>
+ *
+ * Author of bandpass filtersweep effect:
+ * Maarten de Boer <mdeboer@iua.upf.es>
+ *
+ * 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 library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library 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 Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include "../include/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 latency_min = 32; /* in frames */
-int latency_max = 2048; /* in frames */
+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 tick_time = 0; /* disabled, otherwise in us */
+int tick_time_ok = 0;
+int use_poll = 0;
unsigned long loop_limit;
snd_output_t *output = NULL;
-#if 0
-static char *xitoa(int aaa)
-{
- static char str[12];
-
- sprintf(str, "%i", aaa);
- return str;
-}
-#endif
-
-/*
- * 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.
- *
- * Used format is 44100Hz, Signed Little Endian 16-bit, Stereo.
- */
-
int setparams_stream(snd_pcm_t *handle,
snd_pcm_hw_params_t *params,
const char *id)
snd_pcm_sw_params_t *swparams,
const char *id)
{
- int err;
+ int err, val, sleep_min = 0;
err = snd_pcm_hw_params(handle, params);
if (err < 0) {
printf("Unable to set start threshold mode for %s: %s\n", id, snd_strerror(err));
return err;
}
- err = snd_pcm_sw_params_set_avail_min(handle, swparams, !block ? 4 : snd_pcm_hw_params_get_period_size(params, NULL));
+ tick_time_ok = 0;
+ if (tick_time > 0) {
+ int time, ttime;
+ time = snd_pcm_hw_params_get_period_time(params, NULL);
+ ttime = snd_pcm_hw_params_get_tick_time(params, NULL);
+ if (time < ttime) {
+ printf("Skipping to set minimal sleep: period time < tick time\n");
+ } else if (ttime <= 0) {
+ printf("Skipping to set minimal sleep: tick time <= 0 (%i)\n", ttime);
+ } else {
+ sleep_min = tick_time / ttime;
+ if (sleep_min <= 0)
+ sleep_min = 1;
+ err = snd_pcm_sw_params_set_sleep_min(handle, swparams, sleep_min);
+ if (err < 0) {
+ printf("Unable to set minimal sleep %i for %s: %s\n", sleep_min, id, snd_strerror(err));
+ return err;
+ }
+ tick_time_ok = sleep_min * ttime;
+ }
+ }
+ val = !block ? 4 : snd_pcm_hw_params_get_period_size(params, NULL);
+ if (tick_time_ok > 0)
+ val = 16;
+ 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_set_xfer_align(handle, swparams, !block ? 4 : 1);
+ val = !block ? 4 : 1;
+ err = snd_pcm_sw_params_set_xfer_align(handle, swparams, val);
if (err < 0) {
printf("Unable to set transfer align for %s: %s\n", id, snd_strerror(err));
return err;
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;
return (t1.tv_sec * 1000000) + l;
}
-long readbuf(snd_pcm_t *handle, char *buf, long len, size_t *frames)
+long readbuf(snd_pcm_t *handle, char *buf, long len, size_t *frames, size_t *max)
{
long r;
do {
r = snd_pcm_readi(handle, buf, len);
} while (r == -EAGAIN);
- if (r > 0)
+ if (r > 0) {
*frames += r;
+ if (*max < r)
+ *max = r;
+ }
// printf("read = %li\n", r);
} else {
int frame_bytes = (snd_pcm_format_width(format) / 8) * channels;
buf += r * frame_bytes;
len -= r;
*frames += r;
+ if (*max < r)
+ *max = r;
}
// printf("r = %li, len = %li\n", r, len);
} while (r >= 1 && len > 0);
}
return 0;
}
+
+#define FILTERSWEEP_LFO_CENTER 2000.
+#define FILTERSWEEP_LFO_DEPTH 1800.
+#define FILTERSWEEP_LFO_FREQ 0.2
+#define FILTER_BANDWIDTH 50
+
+/* filter 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)
{
-r,--rate rate
-s,--seconds duration of test in seconds
-b,--block block mode
+-t,--time maximal tick time in us
+-p,--poll use poll (wait for event - reduces CPU usage)
+-e,--effect apply an effect (bandpass filtersweep)
");
printf("Recognized sample formats are:");
for (k = 0; k < SND_PCM_FORMAT_LAST; ++(unsigned long) k) {
if (s)
printf(" %s", s);
}
- printf("\n");
+ printf("\n\n");
+ printf("\
+Tip #1 (useable latency with large periods, non-blocking mode, good CPU usage,
+ superb xrun prevention):
+ latency -m 8192 -M 8192 -t 1 -p
+Tip #2 (superb latency, non-blocking mode, but heavy CPU usage):
+ latency -m 128 -M 128
+");
}
int main(int argc, char *argv[])
{"rate", 1, NULL, 'r'},
{"seconds", 1, NULL, 's'},
{"block", 0, NULL, 'b'},
+ {"time", 1, NULL, 't'},
+ {"poll", 0, NULL, 'p'},
+ {"effect", 0, NULL, 'e'},
{NULL, 0, NULL, 0},
};
snd_pcm_t *phandle, *chandle;
char *buffer;
int err, latency, morehelp;
- int size, ok;
+ int ok;
snd_timestamp_t p_tstamp, c_tstamp;
ssize_t r;
- size_t frames_in, frames_out;
-
+ 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:s:b", long_option, NULL)) < 0)
+ if ((c = getopt_long(argc, argv, "hP:C:m:M:F:f:c:r:s:bt:pe", long_option, NULL)) < 0)
break;
switch (c) {
case 'h':
cdevice = strdup(optarg);
break;
case 'm':
- err = atoi(optarg);
+ 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);
+ err = atoi(optarg) / 2;
latency_max = latency_min > err ? latency_min : err;
break;
case 'F':
case 'b':
block = 1;
break;
+ case 't':
+ tick_time = atoi(optarg);
+ tick_time = tick_time < 0 ? 0 : tick_time;
+ break;
+ case 'p':
+ use_poll = 1;
+ break;
+ case 'e':
+ effect = 1;
+ break;
}
}
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("Loop limit is %li frames, minimum latency = %i, maximum latency = %i\n", loop_limit, latency_min, latency_max);
+ printf("Wanted tick time: %ius, poll mode: %s\n", tick_time, 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));
printf("Record open error: %s\n", snd_strerror(err));
return 0;
}
-
+
+ /* initialize 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;
- printf("Trying latency %i frames...\n", latency);
+ showlatency(latency);
+ if (tick_time_ok)
+ printf("Using tick time %ius\n", tick_time_ok);
if ((err = snd_pcm_link(chandle, phandle)) < 0) {
printf("Streams link error: %s\n", snd_strerror(err));
exit(0);
printf("Capture:\n");
showstat(chandle, frames_in);
#endif
+
ok = 1;
- size = 0;
+ in_max = 0;
while (ok && frames_in < loop_limit) {
- if ((r = readbuf(chandle, buffer, latency, &frames_in)) < 0)
- ok = 0;
- else if (writebuf(phandle, buffer, r, &frames_out) < 0)
+ 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");
git://git.alsa-project.org / alsa-lib.git / commitdiff