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<hr><h1>/test/latency.c</h1>
<p>
<a name="example_test_latency"></a>
<p>
<div class="fragment"><pre><span class="comment">/*</span>
<span class="comment"> * Latency test program</span>
<span class="comment"> *</span>
<span class="comment"> * Author: Jaroslav Kysela <perex@suse.cz></span>
<span class="comment"> *</span>
<span class="comment"> * Author of bandpass filter sweep effect:</span>
<span class="comment"> * Maarten de Boer <mdeboer@iua.upf.es></span>
<span class="comment"> *</span>
<span class="comment"> * This small demo program can be used for measuring latency between</span>
<span class="comment"> * capture and playback. This latency is measured from driver (diff when</span>
<span class="comment"> * playback and capture was started). Scheduler is set to SCHED_RR.</span>
<span class="comment"> *</span>
<span class="comment"> *</span>
<span class="comment"> * This program is free software; you can redistribute it and/or modify</span>
<span class="comment"> * it under the terms of the GNU General Public License as published by</span>
<span class="comment"> * the Free Software Foundation; either version 2 of the License, or</span>
<span class="comment"> * (at your option) any later version.</span>
<span class="comment"> *</span>
<span class="comment"> * This program is distributed in the hope that it will be useful,</span>
<span class="comment"> * but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<span class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</span>
<span class="comment"> * GNU General Public License for more details.</span>
<span class="comment"> *</span>
<span class="comment"> * You should have received a copy of the GNU General Public License</span>
<span class="comment"> * along with this program; if not, write to the Free Software</span>
<span class="comment"> * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA</span>
<span class="comment"> *</span>
<span class="comment"> */</span>
<span class="preprocessor">#include <stdio.h></span>
<span class="preprocessor">#include <stdlib.h></span>
<span class="preprocessor">#include <string.h></span>
<span class="preprocessor">#include <sched.h></span>
<span class="preprocessor">#include <errno.h></span>
<span class="preprocessor">#include <getopt.h></span>
<span class="preprocessor">#define ALSA_PCM_NEW_HW_PARAMS_API</span>
<span class="preprocessor"></span><span class="preprocessor">#define ALSA_PCM_NEW_SW_PARAMS_API</span>
<span class="preprocessor"></span><span class="preprocessor">#include "../include/asoundlib.h"</span>
<span class="preprocessor">#include <sys/time.h></span>
<span class="preprocessor">#include <math.h></span>
<span class="keywordtype">char</span> *pdevice = <span class="stringliteral">"hw:0,0"</span>;
<span class="keywordtype">char</span> *cdevice = <span class="stringliteral">"hw:0,0"</span>;
<a class="code" href="group___p_c_m.html#a11">snd_pcm_format_t</a> format = <a class="code" href="group___p_c_m.html#a70a59">SND_PCM_FORMAT_S16_LE</a>;
<span class="keywordtype">int</span> rate = 22050;
<span class="keywordtype">int</span> channels = 2;
<span class="keywordtype">int</span> latency_min = 32; <span class="comment">/* in frames / 2 */</span>
<span class="keywordtype">int</span> latency_max = 2048; <span class="comment">/* in frames / 2 */</span>
<span class="keywordtype">int</span> loop_sec = 30; <span class="comment">/* seconds */</span>
<span class="keywordtype">int</span> block = 0; <span class="comment">/* block mode */</span>
<span class="keywordtype">int</span> tick_time = 0; <span class="comment">/* disabled, otherwise in us */</span>
<span class="keywordtype">int</span> tick_time_ok = 0;
<span class="keywordtype">int</span> use_poll = 0;
<span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> loop_limit;
<a class="code" href="group___output.html#a0">snd_output_t</a> *output = NULL;
<span class="keywordtype">int</span> setparams_stream(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle,
<a class="code" href="group___p_c_m.html#a1">snd_pcm_hw_params_t</a> *params,
<span class="keyword">const</span> <span class="keywordtype">char</span> *id)
{
<span class="keywordtype">int</span> err;
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> rrate;
err = <a name="a0"></a><a class="code" href="group___p_c_m___h_w___params.html#a0">snd_pcm_hw_params_any</a>(handle, params);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Broken configuration for %s PCM: no configurations available: %s\n"</span>, <a name="a1"></a><a class="code" href="group___error.html#a2">snd_strerror</a>(err), id);
<span class="keywordflow">return</span> err;
}
err = <a name="a2"></a><a class="code" href="group___p_c_m___h_w___params.html#a21">snd_pcm_hw_params_set_access</a>(handle, params, <a class="code" href="group___p_c_m.html#a69a53">SND_PCM_ACCESS_RW_INTERLEAVED</a>);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Access type not available for %s: %s\n"</span>, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
err = <a name="a3"></a><a class="code" href="group___p_c_m___h_w___params.html#a30">snd_pcm_hw_params_set_format</a>(handle, params, format);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Sample format not available for %s: %s\n"</span>, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
err = <a name="a4"></a><a class="code" href="group___p_c_m___h_w___params.html#a54">snd_pcm_hw_params_set_channels</a>(handle, params, channels);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Channels count (%i) not available for %s: %s\n"</span>, channels, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
rrate = rate;
err = <a name="a5"></a><a class="code" href="group___p_c_m___h_w___params.html#a75">snd_pcm_hw_params_set_rate_near</a>(handle, params, &rrate, 0);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Rate %iHz not available for %s: %s\n"</span>, rate, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="keywordflow">if</span> (rrate != rate) {
printf(<span class="stringliteral">"Rate doesn't match (requested %iHz, get %iHz)\n"</span>, rate, err);
<span class="keywordflow">return</span> -EINVAL;
}
<span class="keywordflow">return</span> 0;
}
<span class="keywordtype">int</span> setparams_bufsize(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle,
<a class="code" href="group___p_c_m.html#a1">snd_pcm_hw_params_t</a> *params,
<a class="code" href="group___p_c_m.html#a1">snd_pcm_hw_params_t</a> *tparams,
<a class="code" href="group___p_c_m.html#a17">snd_pcm_uframes_t</a> bufsize,
<span class="keyword">const</span> <span class="keywordtype">char</span> *id)
{
<span class="keywordtype">int</span> err;
<a class="code" href="group___p_c_m.html#a17">snd_pcm_uframes_t</a> periodsize;
<a name="a6"></a><a class="code" href="group___p_c_m___h_w___params.html#a17">snd_pcm_hw_params_copy</a>(params, tparams);
periodsize = bufsize * 2;
err = <a name="a7"></a><a class="code" href="group___p_c_m___h_w___params.html#a162">snd_pcm_hw_params_set_buffer_size_near</a>(handle, params, &periodsize);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set buffer size %li for %s: %s\n"</span>, bufsize * 2, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
periodsize /= 2;
err = <a name="a8"></a><a class="code" href="group___p_c_m___h_w___params.html#a109">snd_pcm_hw_params_set_period_size_near</a>(handle, params, &periodsize, 0);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set period size %li for %s: %s\n"</span>, periodsize, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="keywordflow">return</span> 0;
}
<span class="keywordtype">int</span> setparams_set(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle,
<a class="code" href="group___p_c_m.html#a1">snd_pcm_hw_params_t</a> *params,
<a class="code" href="group___p_c_m.html#a2">snd_pcm_sw_params_t</a> *swparams,
<span class="keyword">const</span> <span class="keywordtype">char</span> *id)
{
<span class="keywordtype">int</span> err;
<a class="code" href="group___p_c_m.html#a17">snd_pcm_uframes_t</a> val;
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> sleep_min = 0;
err = <a name="a9"></a><a class="code" href="group___p_c_m.html#a39">snd_pcm_hw_params</a>(handle, params);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set hw params for %s: %s\n"</span>, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
err = <a name="a10"></a><a class="code" href="group___p_c_m.html#a41">snd_pcm_sw_params_current</a>(handle, swparams);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to determine current swparams for %s: %s\n"</span>, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
err = <a name="a11"></a><a class="code" href="group___p_c_m___s_w___params.html#a12">snd_pcm_sw_params_set_start_threshold</a>(handle, swparams, 0x7fffffff);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set start threshold mode for %s: %s\n"</span>, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
tick_time_ok = 0;
<span class="keywordflow">if</span> (tick_time > 0) {
<span class="keywordtype">int</span> time, ttime;
<a name="a12"></a><a class="code" href="group___p_c_m___h_w___params.html#a81">snd_pcm_hw_params_get_period_time</a>(params, &time, NULL);
<a name="a13"></a><a class="code" href="group___p_c_m___h_w___params.html#a168">snd_pcm_hw_params_get_tick_time</a>(params, &ttime, NULL);
<span class="keywordflow">if</span> (time < ttime) {
printf(<span class="stringliteral">"Skipping to set minimal sleep: period time < tick time\n"</span>);
} <span class="keywordflow">else</span> <span class="keywordflow">if</span> (ttime <= 0) {
printf(<span class="stringliteral">"Skipping to set minimal sleep: tick time <= 0 (%i)\n"</span>, ttime);
} <span class="keywordflow">else</span> {
sleep_min = tick_time / ttime;
<span class="keywordflow">if</span> (sleep_min <= 0)
sleep_min = 1;
err = <a name="a14"></a><a class="code" href="group___p_c_m___s_w___params.html#a6">snd_pcm_sw_params_set_sleep_min</a>(handle, swparams, sleep_min);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set minimal sleep %i for %s: %s\n"</span>, sleep_min, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
tick_time_ok = sleep_min * ttime;
}
}
<span class="keywordflow">if</span> (!block)
val = 4;
<span class="keywordflow">else</span>
<a name="a15"></a><a class="code" href="group___p_c_m___h_w___params.html#a98">snd_pcm_hw_params_get_period_size</a>(params, &val, NULL);
<span class="keywordflow">if</span> (tick_time_ok > 0)
val = 16;
err = <a name="a16"></a><a class="code" href="group___p_c_m___s_w___params.html#a8">snd_pcm_sw_params_set_avail_min</a>(handle, swparams, val);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set avail min for %s: %s\n"</span>, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
val = !block ? 4 : 1;
err = <a name="a17"></a><a class="code" href="group___p_c_m___s_w___params.html#a10">snd_pcm_sw_params_set_xfer_align</a>(handle, swparams, val);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set transfer align for %s: %s\n"</span>, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
err = <a name="a18"></a><a class="code" href="group___p_c_m.html#a42">snd_pcm_sw_params</a>(handle, swparams);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set sw params for %s: %s\n"</span>, id, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="keywordflow">return</span> 0;
}
<span class="keywordtype">int</span> setparams(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *phandle, <a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *chandle, <span class="keywordtype">int</span> *bufsize)
{
<span class="keywordtype">int</span> err, last_bufsize = *bufsize;
<a class="code" href="group___p_c_m.html#a1">snd_pcm_hw_params_t</a> *pt_params, *ct_params; <span class="comment">/* templates with rate, format and channels */</span>
<a class="code" href="group___p_c_m.html#a1">snd_pcm_hw_params_t</a> *p_params, *c_params;
<a class="code" href="group___p_c_m.html#a2">snd_pcm_sw_params_t</a> *p_swparams, *c_swparams;
<a class="code" href="group___p_c_m.html#a17">snd_pcm_uframes_t</a> size, p_size, c_size, p_psize, c_psize;
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> p_time, c_time;
<a name="a19"></a><a class="code" href="group___p_c_m___h_w___params.html#a186">snd_pcm_hw_params_alloca</a>(&p_params);
<a class="code" href="group___p_c_m___h_w___params.html#a186">snd_pcm_hw_params_alloca</a>(&c_params);
<a class="code" href="group___p_c_m___h_w___params.html#a186">snd_pcm_hw_params_alloca</a>(&pt_params);
<a class="code" href="group___p_c_m___h_w___params.html#a186">snd_pcm_hw_params_alloca</a>(&ct_params);
<a name="a20"></a><a class="code" href="group___p_c_m___s_w___params.html#a20">snd_pcm_sw_params_alloca</a>(&p_swparams);
<a class="code" href="group___p_c_m___s_w___params.html#a20">snd_pcm_sw_params_alloca</a>(&c_swparams);
<span class="keywordflow">if</span> ((err = setparams_stream(phandle, pt_params, <span class="stringliteral">"playback"</span>)) < 0) {
printf(<span class="stringliteral">"Unable to set parameters for playback stream: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(0);
}
<span class="keywordflow">if</span> ((err = setparams_stream(chandle, ct_params, <span class="stringliteral">"capture"</span>)) < 0) {
printf(<span class="stringliteral">"Unable to set parameters for playback stream: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(0);
}
__again:
<span class="keywordflow">if</span> (last_bufsize == *bufsize)
*bufsize += 4;
last_bufsize = *bufsize;
<span class="keywordflow">if</span> (*bufsize > latency_max)
<span class="keywordflow">return</span> -1;
<span class="keywordflow">if</span> ((err = setparams_bufsize(phandle, p_params, pt_params, *bufsize, <span class="stringliteral">"playback"</span>)) < 0) {
printf(<span class="stringliteral">"Unable to set sw parameters for playback stream: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(0);
}
<span class="keywordflow">if</span> ((err = setparams_bufsize(chandle, c_params, ct_params, *bufsize, <span class="stringliteral">"capture"</span>)) < 0) {
printf(<span class="stringliteral">"Unable to set sw parameters for playback stream: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(0);
}
<a class="code" href="group___p_c_m___h_w___params.html#a98">snd_pcm_hw_params_get_period_size</a>(p_params, &size, NULL);
<span class="keywordflow">if</span> (size > *bufsize)
*bufsize = size;
<a class="code" href="group___p_c_m___h_w___params.html#a98">snd_pcm_hw_params_get_period_size</a>(c_params, &size, NULL);
<span class="keywordflow">if</span> (size > *bufsize)
*bufsize = size;
<a class="code" href="group___p_c_m___h_w___params.html#a81">snd_pcm_hw_params_get_period_time</a>(p_params, &p_time, NULL);
<a class="code" href="group___p_c_m___h_w___params.html#a81">snd_pcm_hw_params_get_period_time</a>(c_params, &c_time, NULL);
<span class="keywordflow">if</span> (p_time != c_time)
<span class="keywordflow">goto</span> __again;
<a class="code" href="group___p_c_m___h_w___params.html#a98">snd_pcm_hw_params_get_period_size</a>(p_params, &p_psize, NULL);
<a name="a21"></a><a class="code" href="group___p_c_m___h_w___params.html#a151">snd_pcm_hw_params_get_buffer_size</a>(p_params, &p_size);
<span class="keywordflow">if</span> (p_psize * 2 < p_size)
<span class="keywordflow">goto</span> __again;
<a class="code" href="group___p_c_m___h_w___params.html#a98">snd_pcm_hw_params_get_period_size</a>(c_params, &c_psize, NULL);
<a class="code" href="group___p_c_m___h_w___params.html#a151">snd_pcm_hw_params_get_buffer_size</a>(c_params, &c_size);
<span class="keywordflow">if</span> (c_psize * 2 < c_size)
<span class="keywordflow">goto</span> __again;
<span class="keywordflow">if</span> ((err = setparams_set(phandle, p_params, p_swparams, <span class="stringliteral">"playback"</span>)) < 0) {
printf(<span class="stringliteral">"Unable to set sw parameters for playback stream: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(0);
}
<span class="keywordflow">if</span> ((err = setparams_set(chandle, c_params, c_swparams, <span class="stringliteral">"capture"</span>)) < 0) {
printf(<span class="stringliteral">"Unable to set sw parameters for playback stream: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(0);
}
<span class="keywordflow">if</span> ((err = <a name="a22"></a><a class="code" href="group___p_c_m.html#a43">snd_pcm_prepare</a>(phandle)) < 0) {
printf(<span class="stringliteral">"Prepare error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(0);
}
<a name="a23"></a><a class="code" href="group___p_c_m___dump.html#a0">snd_pcm_dump</a>(phandle, output);
<a class="code" href="group___p_c_m___dump.html#a0">snd_pcm_dump</a>(chandle, output);
fflush(stdout);
<span class="keywordflow">return</span> 0;
}
<span class="keywordtype">void</span> showstat(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle, size_t frames)
{
<span class="keywordtype">int</span> err;
<a class="code" href="group___p_c_m.html#a3">snd_pcm_status_t</a> *status;
<a name="a24"></a><a class="code" href="group___p_c_m___status.html#a11">snd_pcm_status_alloca</a>(&status);
<span class="keywordflow">if</span> ((err = <a name="a25"></a><a class="code" href="group___p_c_m.html#a45">snd_pcm_status</a>(handle, status)) < 0) {
printf(<span class="stringliteral">"Stream status error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(0);
}
printf(<span class="stringliteral">"*** frames = %li ***\n"</span>, (<span class="keywordtype">long</span>)frames);
<a name="a26"></a><a class="code" href="group___p_c_m___dump.html#a6">snd_pcm_status_dump</a>(status, output);
}
<span class="keywordtype">void</span> showlatency(size_t latency)
{
<span class="keywordtype">double</span> d;
latency *= 2;
d = (double)latency / (double)rate;
printf(<span class="stringliteral">"Trying latency %li frames, %.3fus, %.6fms (%.4fHz)\n"</span>, (<span class="keywordtype">long</span>)latency, d * 1000000, d * 1000, (<span class="keywordtype">double</span>)1 / d);
}
<span class="keywordtype">void</span> showinmax(size_t in_max)
{
<span class="keywordtype">double</span> d;
printf(<span class="stringliteral">"Maximum read: %li frames\n"</span>, (<span class="keywordtype">long</span>)in_max);
d = (double)in_max / (double)rate;
printf(<span class="stringliteral">"Maximum read latency: %.3fus, %.6fms (%.4fHz)\n"</span>, d * 1000000, d * 1000, (<span class="keywordtype">double</span>)1 / d);
}
<span class="keywordtype">void</span> gettimestamp(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle, <a class="code" href="group___p_c_m.html#a19">snd_timestamp_t</a> *timestamp)
{
<span class="keywordtype">int</span> err;
<a class="code" href="group___p_c_m.html#a3">snd_pcm_status_t</a> *status;
<a class="code" href="group___p_c_m___status.html#a11">snd_pcm_status_alloca</a>(&status);
<span class="keywordflow">if</span> ((err = <a class="code" href="group___p_c_m.html#a45">snd_pcm_status</a>(handle, status)) < 0) {
printf(<span class="stringliteral">"Stream status error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(0);
}
<a name="a27"></a><a class="code" href="group___p_c_m___status.html#a5">snd_pcm_status_get_trigger_tstamp</a>(status, timestamp);
}
<span class="keywordtype">void</span> setscheduler(<span class="keywordtype">void</span>)
{
<span class="keyword">struct </span>sched_param sched_param;
<span class="keywordflow">if</span> (sched_getparam(0, &sched_param) < 0) {
printf(<span class="stringliteral">"Scheduler getparam failed...\n"</span>);
<span class="keywordflow">return</span>;
}
sched_param.sched_priority = sched_get_priority_max(SCHED_RR);
<span class="keywordflow">if</span> (!sched_setscheduler(0, SCHED_RR, &sched_param)) {
printf(<span class="stringliteral">"Scheduler set to Round Robin with priority %i...\n"</span>, sched_param.sched_priority);
fflush(stdout);
<span class="keywordflow">return</span>;
}
printf(<span class="stringliteral">"!!!Scheduler set to Round Robin with priority %i FAILED!!!\n"</span>, sched_param.sched_priority);
}
<span class="keywordtype">long</span> timediff(<a class="code" href="group___p_c_m.html#a19">snd_timestamp_t</a> t1, <a class="code" href="group___p_c_m.html#a19">snd_timestamp_t</a> t2)
{
<span class="keywordtype">signed</span> <span class="keywordtype">long</span> l;
t1.tv_sec -= t2.tv_sec;
l = (<span class="keywordtype">signed</span> <span class="keywordtype">long</span>) t1.tv_usec - (<span class="keywordtype">signed</span> <span class="keywordtype">long</span>) t2.tv_usec;
<span class="keywordflow">if</span> (l < 0) {
t1.tv_sec--;
l = -l;
l %= 1000000;
}
<span class="keywordflow">return</span> (t1.tv_sec * 1000000) + l;
}
<span class="keywordtype">long</span> readbuf(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle, <span class="keywordtype">char</span> *buf, <span class="keywordtype">long</span> len, size_t *frames, size_t *max)
{
<span class="keywordtype">long</span> r;
<span class="keywordflow">if</span> (!block) {
<span class="keywordflow">do</span> {
r = <a name="a28"></a><a class="code" href="group___p_c_m.html#a57">snd_pcm_readi</a>(handle, buf, len);
} <span class="keywordflow">while</span> (r == -EAGAIN);
<span class="keywordflow">if</span> (r > 0) {
*frames += r;
<span class="keywordflow">if</span> (*max < r)
*max = r;
}
<span class="comment">// printf("read = %li\n", r);</span>
} <span class="keywordflow">else</span> {
<span class="keywordtype">int</span> frame_bytes = (<a name="a29"></a><a class="code" href="group___p_c_m___helpers.html#a7">snd_pcm_format_width</a>(format) / 8) * channels;
<span class="keywordflow">do</span> {
r = <a class="code" href="group___p_c_m.html#a57">snd_pcm_readi</a>(handle, buf, len);
<span class="keywordflow">if</span> (r > 0) {
buf += r * frame_bytes;
len -= r;
*frames += r;
<span class="keywordflow">if</span> (*max < r)
*max = r;
}
<span class="comment">// printf("r = %li, len = %li\n", r, len);</span>
} <span class="keywordflow">while</span> (r >= 1 && len > 0);
}
<span class="comment">// showstat(handle, 0);</span>
<span class="keywordflow">return</span> r;
}
<span class="keywordtype">long</span> writebuf(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle, <span class="keywordtype">char</span> *buf, <span class="keywordtype">long</span> len, size_t *frames)
{
<span class="keywordtype">long</span> r;
<span class="keywordflow">while</span> (len > 0) {
r = <a name="a30"></a><a class="code" href="group___p_c_m.html#a56">snd_pcm_writei</a>(handle, buf, len);
<span class="keywordflow">if</span> (r == -EAGAIN)
<span class="keywordflow">continue</span>;
<span class="comment">// printf("write = %li\n", r);</span>
<span class="keywordflow">if</span> (r < 0)
<span class="keywordflow">return</span> r;
<span class="comment">// showstat(handle, 0);</span>
buf += r * 4;
len -= r;
*frames += r;
}
<span class="keywordflow">return</span> 0;
}
<span class="preprocessor">#define FILTERSWEEP_LFO_CENTER 2000.</span>
<span class="preprocessor"></span><span class="preprocessor">#define FILTERSWEEP_LFO_DEPTH 1800.</span>
<span class="preprocessor"></span><span class="preprocessor">#define FILTERSWEEP_LFO_FREQ 0.2</span>
<span class="preprocessor"></span><span class="preprocessor">#define FILTER_BANDWIDTH 50</span>
<span class="preprocessor"></span>
<span class="comment">/* filter the sweep variables */</span>
<span class="keywordtype">float</span> lfo,dlfo,fs,fc,BW,C,D,a0,a1,a2,b1,b2,*x[3],*y[3];
<span class="keywordtype">void</span> applyeffect(<span class="keywordtype">char</span>* buffer,<span class="keywordtype">int</span> r)
{
<span class="keywordtype">short</span>* samples = (<span class="keywordtype">short</span>*) buffer;
<span class="keywordtype">int</span> i;
<span class="keywordflow">for</span> (i=0;i<r;i++)
{
<span class="keywordtype">int</span> chn;
fc = sin(lfo)*FILTERSWEEP_LFO_DEPTH+FILTERSWEEP_LFO_CENTER;
lfo += dlfo;
<span class="keywordflow">if</span> (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;
<span class="keywordflow">for</span> (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];
}
}
}
<span class="keywordtype">void</span> help(<span class="keywordtype">void</span>)
{
<span class="keywordtype">int</span> k;
printf(<span class="stringliteral">"\</span>
<span class="stringliteral">Usage: latency [OPTION]... [FILE]...</span>
<span class="stringliteral">-h,--help help</span>
<span class="stringliteral">-P,--pdevice playback device</span>
<span class="stringliteral">-C,--cdevice capture device</span>
<span class="stringliteral">-m,--min minimum latency in frames</span>
<span class="stringliteral">-M,--max maximum latency in frames</span>
<span class="stringliteral">-F,--frames frames to transfer</span>
<span class="stringliteral">-f,--format sample format</span>
<span class="stringliteral">-c,--channels channels</span>
<span class="stringliteral">-r,--rate rate</span>
<span class="stringliteral">-s,--seconds duration of test in seconds</span>
<span class="stringliteral">-b,--block block mode</span>
<span class="stringliteral">-t,--time maximal tick time in us</span>
<span class="stringliteral">-p,--poll use poll (wait for event - reduces CPU usage)</span>
<span class="stringliteral">-e,--effect apply an effect (bandpass filter sweep)</span>
<span class="stringliteral">"</span>);
printf(<span class="stringliteral">"Recognized sample formats are:"</span>);
<span class="keywordflow">for</span> (k = 0; k < SND_PCM_FORMAT_LAST; ++(<span class="keywordtype">unsigned</span> <span class="keywordtype">long</span>) k) {
<span class="keyword">const</span> <span class="keywordtype">char</span> *s = <a name="a31"></a><a class="code" href="group___p_c_m___description.html#a2">snd_pcm_format_name</a>(k);
<span class="keywordflow">if</span> (s)
printf(<span class="stringliteral">" %s"</span>, s);
}
printf(<span class="stringliteral">"\n\n"</span>);
printf(<span class="stringliteral">"\</span>
<span class="stringliteral">Tip #1 (usable latency with large periods, non-blocking mode, good CPU usage,</span>
<span class="stringliteral"> superb xrun prevention):</span>
<span class="stringliteral"> latency -m 8192 -M 8192 -t 1 -p</span>
<span class="stringliteral">Tip #2 (superb latency, non-blocking mode, but heavy CPU usage):</span>
<span class="stringliteral"> latency -m 128 -M 128</span>
<span class="stringliteral">"</span>);
}
<span class="keywordtype">int</span> main(<span class="keywordtype">int</span> argc, <span class="keywordtype">char</span> *argv[])
{
<span class="keyword">struct </span>option long_option[] =
{
{<span class="stringliteral">"help"</span>, 0, NULL, <span class="charliteral">'h'</span>},
{<span class="stringliteral">"pdevice"</span>, 1, NULL, <span class="charliteral">'P'</span>},
{<span class="stringliteral">"cdevice"</span>, 1, NULL, <span class="charliteral">'C'</span>},
{<span class="stringliteral">"min"</span>, 1, NULL, <span class="charliteral">'m'</span>},
{<span class="stringliteral">"max"</span>, 1, NULL, <span class="charliteral">'M'</span>},
{<span class="stringliteral">"frames"</span>, 1, NULL, <span class="charliteral">'F'</span>},
{<span class="stringliteral">"format"</span>, 1, NULL, <span class="charliteral">'f'</span>},
{<span class="stringliteral">"channels"</span>, 1, NULL, <span class="charliteral">'c'</span>},
{<span class="stringliteral">"rate"</span>, 1, NULL, <span class="charliteral">'r'</span>},
{<span class="stringliteral">"seconds"</span>, 1, NULL, <span class="charliteral">'s'</span>},
{<span class="stringliteral">"block"</span>, 0, NULL, <span class="charliteral">'b'</span>},
{<span class="stringliteral">"time"</span>, 1, NULL, <span class="charliteral">'t'</span>},
{<span class="stringliteral">"poll"</span>, 0, NULL, <span class="charliteral">'p'</span>},
{<span class="stringliteral">"effect"</span>, 0, NULL, <span class="charliteral">'e'</span>},
{NULL, 0, NULL, 0},
};
<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *phandle, *chandle;
<span class="keywordtype">char</span> *buffer;
<span class="keywordtype">int</span> err, latency, morehelp;
<span class="keywordtype">int</span> ok;
<a class="code" href="group___p_c_m.html#a19">snd_timestamp_t</a> p_tstamp, c_tstamp;
ssize_t r;
size_t frames_in, frames_out, in_max;
<span class="keywordtype">int</span> effect = 0;
morehelp = 0;
<span class="keywordflow">while</span> (1) {
<span class="keywordtype">int</span> c;
<span class="keywordflow">if</span> ((c = getopt_long(argc, argv, <span class="stringliteral">"hP:C:m:M:F:f:c:r:s:bt:pe"</span>, long_option, NULL)) < 0)
<span class="keywordflow">break</span>;
<span class="keywordflow">switch</span> (c) {
<span class="keywordflow">case</span> <span class="charliteral">'h'</span>:
morehelp++;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'P'</span>:
pdevice = strdup(optarg);
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'C'</span>:
cdevice = strdup(optarg);
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'m'</span>:
err = atoi(optarg) / 2;
latency_min = err >= 4 ? err : 4;
<span class="keywordflow">if</span> (latency_max < latency_min)
latency_max = latency_min;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'M'</span>:
err = atoi(optarg) / 2;
latency_max = latency_min > err ? latency_min : err;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'F'</span>:
format = <a name="a32"></a><a class="code" href="group___p_c_m___description.html#a6">snd_pcm_format_value</a>(optarg);
<span class="keywordflow">if</span> (format == <a class="code" href="group___p_c_m.html#a70a56">SND_PCM_FORMAT_UNKNOWN</a>) {
printf(<span class="stringliteral">"Unknown format, setting to default S16_LE\n"</span>);
format = <a class="code" href="group___p_c_m.html#a70a59">SND_PCM_FORMAT_S16_LE</a>;
}
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'c'</span>:
err = atoi(optarg);
channels = err >= 1 && err < 1024 ? err : 1;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'r'</span>:
err = atoi(optarg);
rate = err >= 4000 && err < 200000 ? err : 44100;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'s'</span>:
err = atoi(optarg);
loop_sec = err >= 1 && err <= 100000 ? err : 30;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'b'</span>:
block = 1;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'t'</span>:
tick_time = atoi(optarg);
tick_time = tick_time < 0 ? 0 : tick_time;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'p'</span>:
use_poll = 1;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'e'</span>:
effect = 1;
<span class="keywordflow">break</span>;
}
}
<span class="keywordflow">if</span> (morehelp) {
help();
<span class="keywordflow">return</span> 0;
}
err = <a name="a33"></a><a class="code" href="group___output.html#a3">snd_output_stdio_attach</a>(&output, stdout, 0);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Output failed: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> 0;
}
loop_limit = loop_sec * rate;
latency = latency_min - 4;
buffer = malloc((latency_max * <a class="code" href="group___p_c_m___helpers.html#a7">snd_pcm_format_width</a>(format) / 8) * 2);
setscheduler();
printf(<span class="stringliteral">"Playback device is %s\n"</span>, pdevice);
printf(<span class="stringliteral">"Capture device is %s\n"</span>, cdevice);
printf(<span class="stringliteral">"Parameters are %iHz, %s, %i channels, %s mode\n"</span>, rate, <a class="code" href="group___p_c_m___description.html#a2">snd_pcm_format_name</a>(format), channels, block ? <span class="stringliteral">"blocking"</span> : <span class="stringliteral">"non-blocking"</span>);
printf(<span class="stringliteral">"Wanted tick time: %ius, poll mode: %s\n"</span>, tick_time, use_poll ? <span class="stringliteral">"yes"</span> : <span class="stringliteral">"no"</span>);
printf(<span class="stringliteral">"Loop limit is %li frames, minimum latency = %i, maximum latency = %i\n"</span>, loop_limit, latency_min * 2, latency_max * 2);
<span class="keywordflow">if</span> ((err = <a name="a34"></a><a class="code" href="group___p_c_m.html#a25">snd_pcm_open</a>(&phandle, pdevice, <a class="code" href="group___p_c_m.html#a68a47">SND_PCM_STREAM_PLAYBACK</a>, block ? 0 : <a class="code" href="group___p_c_m.html#a64">SND_PCM_NONBLOCK</a>)) < 0) {
printf(<span class="stringliteral">"Playback open error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> 0;
}
<span class="keywordflow">if</span> ((err = <a class="code" href="group___p_c_m.html#a25">snd_pcm_open</a>(&chandle, cdevice, <a class="code" href="group___p_c_m.html#a68a48">SND_PCM_STREAM_CAPTURE</a>, block ? 0 : <a class="code" href="group___p_c_m.html#a64">SND_PCM_NONBLOCK</a>)) < 0) {
printf(<span class="stringliteral">"Record open error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> 0;
}
<span class="comment">/* initialize the filter sweep variables */</span>
<span class="keywordflow">if</span> (effect) {
fs = (float) rate;
BW = FILTER_BANDWIDTH;
lfo = 0;
dlfo = 2.*M_PI*FILTERSWEEP_LFO_FREQ/fs;
x[0] = (<span class="keywordtype">float</span>*) malloc(channels*<span class="keyword">sizeof</span>(<span class="keywordtype">float</span>));
x[1] = (<span class="keywordtype">float</span>*) malloc(channels*<span class="keyword">sizeof</span>(<span class="keywordtype">float</span>));
x[2] = (<span class="keywordtype">float</span>*) malloc(channels*<span class="keyword">sizeof</span>(<span class="keywordtype">float</span>));
y[0] = (<span class="keywordtype">float</span>*) malloc(channels*<span class="keyword">sizeof</span>(<span class="keywordtype">float</span>));
y[1] = (<span class="keywordtype">float</span>*) malloc(channels*<span class="keyword">sizeof</span>(<span class="keywordtype">float</span>));
y[2] = (<span class="keywordtype">float</span>*) malloc(channels*<span class="keyword">sizeof</span>(<span class="keywordtype">float</span>));
}
<span class="keywordflow">while</span> (1) {
frames_in = frames_out = 0;
<span class="keywordflow">if</span> (setparams(phandle, chandle, &latency) < 0)
<span class="keywordflow">break</span>;
showlatency(latency);
<span class="keywordflow">if</span> (tick_time_ok)
printf(<span class="stringliteral">"Using tick time %ius\n"</span>, tick_time_ok);
<span class="keywordflow">if</span> ((err = <a name="a35"></a><a class="code" href="group___p_c_m.html#a61">snd_pcm_link</a>(chandle, phandle)) < 0) {
printf(<span class="stringliteral">"Streams link error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(0);
}
<span class="keywordflow">if</span> (<a name="a36"></a><a class="code" href="group___p_c_m___helpers.html#a15">snd_pcm_format_set_silence</a>(format, buffer, latency*channels) < 0) {
fprintf(stderr, <span class="stringliteral">"silence error\n"</span>);
<span class="keywordflow">break</span>;
}
<span class="keywordflow">if</span> (writebuf(phandle, buffer, latency, &frames_out) < 0) {
fprintf(stderr, <span class="stringliteral">"write error\n"</span>);
<span class="keywordflow">break</span>;
}
<span class="keywordflow">if</span> (writebuf(phandle, buffer, latency, &frames_out) < 0) {
fprintf(stderr, <span class="stringliteral">"write error\n"</span>);
<span class="keywordflow">break</span>;
}
<span class="keywordflow">if</span> ((err = <a name="a37"></a><a class="code" href="group___p_c_m.html#a46">snd_pcm_start</a>(chandle)) < 0) {
printf(<span class="stringliteral">"Go error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(0);
}
gettimestamp(phandle, &p_tstamp);
gettimestamp(chandle, &c_tstamp);
<span class="preprocessor">#if 0</span>
<span class="preprocessor"></span> printf(<span class="stringliteral">"Playback:\n"</span>);
showstat(phandle, frames_out);
printf(<span class="stringliteral">"Capture:\n"</span>);
showstat(chandle, frames_in);
<span class="preprocessor">#endif</span>
<span class="preprocessor"></span>
ok = 1;
in_max = 0;
<span class="keywordflow">while</span> (ok && frames_in < loop_limit) {
<span class="keywordflow">if</span> (use_poll) {
<span class="comment">/* use poll to wait for next event */</span>
<a name="a38"></a><a class="code" href="group___p_c_m.html#a60">snd_pcm_wait</a>(chandle, 1000);
}
<span class="keywordflow">if</span> ((r = readbuf(chandle, buffer, latency, &frames_in, &in_max)) < 0)
ok = 0;
<span class="keywordflow">else</span> {
<span class="keywordflow">if</span> (effect)
applyeffect(buffer,r);
<span class="keywordflow">if</span> (writebuf(phandle, buffer, r, &frames_out) < 0)
ok = 0;
}
}
<span class="keywordflow">if</span> (ok)
printf(<span class="stringliteral">"Success\n"</span>);
<span class="keywordflow">else</span>
printf(<span class="stringliteral">"Failure\n"</span>);
printf(<span class="stringliteral">"Playback:\n"</span>);
showstat(phandle, frames_out);
printf(<span class="stringliteral">"Capture:\n"</span>);
showstat(chandle, frames_in);
showinmax(in_max);
<span class="keywordflow">if</span> (p_tstamp.tv_sec == p_tstamp.tv_sec &&
p_tstamp.tv_usec == c_tstamp.tv_usec)
printf(<span class="stringliteral">"Hardware sync\n"</span>);
<a name="a39"></a><a class="code" href="group___p_c_m.html#a47">snd_pcm_drop</a>(chandle);
<a name="a40"></a><a class="code" href="group___p_c_m.html#a34">snd_pcm_nonblock</a>(phandle, 0);
<a name="a41"></a><a class="code" href="group___p_c_m.html#a48">snd_pcm_drain</a>(phandle);
<a class="code" href="group___p_c_m.html#a34">snd_pcm_nonblock</a>(phandle, !block ? 1 : 0);
<span class="keywordflow">if</span> (ok) {
<span class="preprocessor">#if 1</span>
<span class="preprocessor"></span> printf(<span class="stringliteral">"Playback time = %li.%i, Record time = %li.%i, diff = %li\n"</span>,
p_tstamp.tv_sec,
(<span class="keywordtype">int</span>)p_tstamp.tv_usec,
c_tstamp.tv_sec,
(<span class="keywordtype">int</span>)c_tstamp.tv_usec,
timediff(p_tstamp, c_tstamp));
<span class="preprocessor">#endif</span>
<span class="preprocessor"></span> <span class="keywordflow">break</span>;
}
<a name="a42"></a><a class="code" href="group___p_c_m.html#a62">snd_pcm_unlink</a>(chandle);
<a name="a43"></a><a class="code" href="group___p_c_m.html#a40">snd_pcm_hw_free</a>(phandle);
<a class="code" href="group___p_c_m.html#a40">snd_pcm_hw_free</a>(chandle);
}
<a name="a44"></a><a class="code" href="group___p_c_m.html#a27">snd_pcm_close</a>(phandle);
<a class="code" href="group___p_c_m.html#a27">snd_pcm_close</a>(chandle);
<span class="keywordflow">return</span> 0;
}
</pre></div><hr><address style="align: right;"><small>Generated on Wed Apr 2 16:06:31 2003 for ALSA project - the C library reference by
<a href="http://www.doxygen.org/index.html">
<img src="doxygen.png" alt="doxygen" align="middle" border=0
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