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Added tool to measure the end to end latency in loopback configuration to investigate #53

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The script run_latency_test.sh can be used to run the test.
The latency utility measures the end to end latency by adding timestamps in the stream at playback time and checking the timestamps when the packets are received on the capture device.
The average measured end to end latency is printed at the end of the test.
The latency utility is based on a modified version of the original ALSA latency tool.
This commit is contained in:
Andrea Bondavalli 2021-12-05 11:07:06 +01:00
parent 77de7ac28f
commit 9725a73cfb
3 changed files with 884 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

137
run_latency_test.sh Executable file
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#!/bin/bash
#
# Tested on Ubuntu 18.04
#
function cleanup {
#kill and wait for previous daemon instances to exit
sudo killall -q ptp4l
killall -q aes67-daemon
while killall -0 aes67-daemon 2>/dev/null ; do
sleep 1
done
}
function usage {
echo 'Usage run_latenvy_test.sh sample_format sample_rate channels duration' >&2
echo ' sample_format can be one of S16_LE, S24_3LE, S32_LE' >&2
echo ' sample_rate can be one of 44100, 48000, 96000' >&2
echo ' channels can be one of 1, 2, 4' >&2
echo ' duration in seconds' >&2
exit 1
}
if [ "$#" -ne 4 ]; then
usage
fi
if ! [ -x "$(command -v /usr/sbin/ptp4l)" ]; then
echo 'Error: ptp4l is not installed.' >&2
exit 1
fi
if ! [ -x "$(command -v arecord)" ]; then
echo 'Error: arecord is not installed.' >&2
exit 1
fi
if ! [ -x "$(command -v aplay)" ]; then
echo 'Error: aplay is not installed.' >&2
exit 1
fi
if ! [ -x "$(command -v ./daemon/aes67-daemon)" ]; then
echo 'Error: aes67-daemon is not compiled.' >&2
exit 1
fi
if ! [ -r "3rdparty/ravenna-alsa-lkm/driver/MergingRavennaALSA.ko" ]; then
echo 'Error: MergingRavennaALSA.ko module is not compiled.' >&2
exit 1
fi
cd test
echo 'Compiling tools ...' >&2
make
cd ..
SAMPLE_FORMAT=$1
SAMPLE_RATE=$2
CHANNELS=$3
DURATION=$4
if [ $SAMPLE_FORMAT == "S16_LE" ]; then
CODEC="L16"
elif [ $SAMPLE_FORMAT == "S24_3LE" ]; then
CODEC="L24"
elif [ $SAMPLE_FORMAT == "S32_LE" ] ; then
CODEC="AM824"
else
usage
fi
if [ $SAMPLE_RATE == "44100" ]; then
PTIME="1.08843537415"
elif [ $SAMPLE_RATE == "48000" ]; then
PTIME="1"
elif [ $SAMPLE_RATE == "96000" ]; then
PTIME="0.5"
else
usage
fi
MAP="[ "
for (( ch=0; ch<$CHANNELS; ch++ ))
do
MAP+=$ch
if (( ch != ($CHANNELS - 1) )); then
MAP+=","
fi
done
MAP+=" ]"
echo 'Creating configuration files ..' >&2
sed 's/48000/'"$SAMPLE_RATE"'/g;s/status.json/status_.json/g;' test/daemon.conf > test/daemon_.conf
sed 's/\/2/\/'"$CHANNELS"'/g;s/48000/'"$SAMPLE_RATE"'/g;s/L24/'"$CODEC"'/g;s/ptime:1/ptime:'"$PTIME"'/;s/\[ 0, 1 \]/'"$MAP"'/g' test/status.json > test/status_.json
trap cleanup EXIT
#configure system parms
sudo sysctl -w net/ipv4/igmp_max_memberships=66
if [ -x /usr/bin/pulseaudio ]; then
#stop pulseaudio, this seems to open/close ALSA continuosly
echo autospawn = no > $HOME/.config/pulse/client.conf
pulseaudio --kill >/dev/null 2>&1
rm $HOME/.config/pulse/client.conf
#disable pulseaudio
systemctl --user stop pulseaudio.socket > /dev/null 2>&1
systemctl --user stop pulseaudio.sservice > /dev/null 2>&1
fi
#uninstall kernel module
if sudo lsmod | grep MergingRavennaALSA > /dev/null 2>&1 ; then
sudo rmmod MergingRavennaALSA
fi
#install kernel module
sudo insmod 3rdparty/ravenna-alsa-lkm/driver/MergingRavennaALSA.ko
cleanup
echo "Starting PTP master ..."
sudo /usr/sbin/ptp4l -i lo -l7 -E -S &
echo "Starting AES67 daemon ..."
./daemon/aes67-daemon -c ./test/daemon_.conf &
echo "Waiting for PTP slave to sync ..."
sleep 30
echo "Running 10 secs latency test"
cd test
./latency -P hw:RAVENNA -C hw:RAVENNA -f $SAMPLE_FORMAT -r $SAMPLE_RATE -c $CHANNELS -M 128 -m 128 -s $DURATION
cd ..
echo "Terminating processes ..."

7
test/Makefile
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@ -1,8 +1,11 @@
CXX=g++
CC=g++
all: check createtest
LIBS=-lpthread -lasound
all: check createtest latency
createtest: createtest.o
check: check.o
latency: latency.o
$(CXX) $< -o latency $(LIBS)
clean:
rm *.o
rm check createtest
rm check createtest latency

742
test/latency.cc Normal file
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/*
* Latency test program
*
* Author: Jaroslav Kysela <perex@perex.cz>
*
* Author of bandpass filter sweep 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 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#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>
#include <chrono>
static unsigned char header[4] = { 0xff, 0xff, 0xff, 0xff };
const char *pdevice = "hw:0,0";
const 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;
uint64_t end_to_end_latency = 0;
uint64_t end_to_end_samples = 0;
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;
//printf("p period_time = %u\n", p_time);
//printf("p period_size = %lu\n", p_size);
//printf("c period_time = %u\n", c_time);
//printf("c period_size = %lu\n", c_size);
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);
//printf("p period_min = %u\n", val);
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);
//printf("c period_min = %u\n", val);
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);
}
uint64_t sentMs, recvMs =
std::chrono::duration_cast<std::chrono::milliseconds>(
std::chrono::system_clock::now().time_since_epoch()).count();
for (int i = 0; i < (r - 12); i++) {
if (!memcmp(buf + i, header, 4)) {
memcpy(&sentMs, buf + i + 4, 8);
//printf("elpased %lu ms\n", recvMs - sentMs);
if ((recvMs - sentMs) < 1000) {
end_to_end_latency += recvMs - sentMs;
end_to_end_samples++;
}
}
}
// showstat(handle, 0);
return r;
}
long writebuf(snd_pcm_t *handle, char *buf, long len, size_t *frames)
{
long r;
int frame_bytes = (snd_pcm_format_width(format) / 8) * channels;
uint64_t ms =
std::chrono::duration_cast<std::chrono::milliseconds>(
std::chrono::system_clock::now().time_since_epoch()).count();
memcpy(buf, header, 4);
memcpy(buf + 4, &ms, sizeof(ms));
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 * frame_bytes;
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((snd_pcm_format_t)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 = (char*)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 %lu 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 == c_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);
}
printf("End to end latency: %lu ms\n", end_to_end_latency / end_to_end_samples);
snd_pcm_close(phandle);
snd_pcm_close(chandle);
return 0;
}