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<hr><h1>/test/pcm.c</h1>
<p>
<a name="example_test_pcm"></a>
<p>
<div class="fragment"><pre><span class="comment">/*</span>
<span class="comment"> * This small demo sends a simple sinusoidal wave to your speakers.</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> *device = <span class="stringliteral">"plughw:0,0"</span>; <span class="comment">/* playback device */</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#a70a96">SND_PCM_FORMAT_S16</a>; <span class="comment">/* sample format */</span>
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> rate = 44100; <span class="comment">/* stream rate */</span>
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> channels = 1; <span class="comment">/* count of channels */</span>
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> buffer_time = 500000; <span class="comment">/* ring buffer length in us */</span>
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> period_time = 100000; <span class="comment">/* period time in us */</span>
<span class="keywordtype">double</span> freq = 440; <span class="comment">/* sinusoidal wave frequency in Hz */</span>
<a class="code" href="group___p_c_m.html#a18">snd_pcm_sframes_t</a> buffer_size;
<a class="code" href="group___p_c_m.html#a18">snd_pcm_sframes_t</a> period_size;
<a class="code" href="group___output.html#a0">snd_output_t</a> *output = NULL;
<span class="keyword">static</span> <span class="keywordtype">void</span> generate_sine(<span class="keyword">const</span> <a name="_a0"></a><a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a> *areas,
<a class="code" href="group___p_c_m.html#a17">snd_pcm_uframes_t</a> offset,
<span class="keywordtype">int</span> count, <span class="keywordtype">double</span> *_phase)
{
<span class="keywordtype">double</span> phase = *_phase;
<span class="keywordtype">double</span> max_phase = 1.0 / freq;
<span class="keywordtype">double</span> step = 1.0 / (double)rate;
<span class="keywordtype">double</span> res;
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples[channels];
<span class="keywordtype">int</span> steps[channels];
<span class="keywordtype">int</span> chn, ires;
<span class="comment">/* verify and prepare the contents of areas */</span>
<span class="keywordflow">for</span> (chn = 0; chn < channels; chn++) {
<span class="keywordflow">if</span> ((areas[chn].<a name="a1"></a><a class="code" href="struct__snd__pcm__channel__area.html#m1">first</a> % 8) != 0) {
printf(<span class="stringliteral">"areas[%i].first == %i, aborting...\n"</span>, chn, areas[chn].first);
exit(EXIT_FAILURE);
}
samples[chn] = (<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *)(((<span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *)areas[chn].<a name="a2"></a><a class="code" href="struct__snd__pcm__channel__area.html#m0">addr</a>) + (areas[chn].<a class="code" href="struct__snd__pcm__channel__area.html#m1">first</a> / 8));
<span class="keywordflow">if</span> ((areas[chn].<a name="a3"></a><a class="code" href="struct__snd__pcm__channel__area.html#m2">step</a> % 16) != 0) {
printf(<span class="stringliteral">"areas[%i].step == %i, aborting...\n"</span>, chn, areas[chn].step);
exit(EXIT_FAILURE);
}
steps[chn] = areas[chn].<a class="code" href="struct__snd__pcm__channel__area.html#m2">step</a> / 16;
samples[chn] += offset * steps[chn];
}
<span class="comment">/* fill the channel areas */</span>
<span class="keywordflow">while</span> (count-- > 0) {
res = sin((phase * 2 * M_PI) / max_phase - M_PI) * 32767;
ires = res;
<span class="keywordflow">for</span> (chn = 0; chn < channels; chn++) {
*samples[chn] = ires;
samples[chn] += steps[chn];
}
phase += step;
<span class="keywordflow">if</span> (phase >= max_phase)
phase -= max_phase;
}
*_phase = phase;
}
<span class="keyword">static</span> <span class="keywordtype">int</span> set_hwparams(<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#a10">snd_pcm_access_t</a> access)
{
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> rrate;
<span class="keywordtype">int</span> err, dir;
<span class="comment">/* choose all parameters */</span>
err = <a name="a4"></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 playback: no configurations available: %s\n"</span>, <a name="a5"></a><a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* set the interleaved read/write format */</span>
err = <a name="a6"></a><a class="code" href="group___p_c_m___h_w___params.html#a21">snd_pcm_hw_params_set_access</a>(handle, params, access);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Access type not available for playback: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* set the sample format */</span>
err = <a name="a7"></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 playback: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* set the count of channels */</span>
err = <a name="a8"></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 playbacks: %s\n"</span>, channels, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* set the stream rate */</span>
rrate = rate;
err = <a name="a9"></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 playback: %s\n"</span>, rate, <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="comment">/* set the buffer time */</span>
err = <a name="a10"></a><a class="code" href="group___p_c_m___h_w___params.html#a145">snd_pcm_hw_params_set_buffer_time_near</a>(handle, params, &buffer_time, &dir);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set buffer time %i for playback: %s\n"</span>, buffer_time, <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___h_w___params.html#a151">snd_pcm_hw_params_get_buffer_size</a>(params, &buffer_size);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to get buffer size for playback: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* set the period time */</span>
err = <a name="a12"></a><a class="code" href="group___p_c_m___h_w___params.html#a92">snd_pcm_hw_params_set_period_time_near</a>(handle, params, &period_time, &dir);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set period time %i for playback: %s\n"</span>, period_time, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
err = <a name="a13"></a><a class="code" href="group___p_c_m___h_w___params.html#a98">snd_pcm_hw_params_get_period_size</a>(params, &period_size, &dir);
<span class="keywordflow">if</span> (err > 0) {
printf(<span class="stringliteral">"Unable to get period size for playback: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* write the parameters to device */</span>
err = <a name="a14"></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 playback: %s\n"</span>, <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="keyword">static</span> <span class="keywordtype">int</span> set_swparams(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle, <a class="code" href="group___p_c_m.html#a2">snd_pcm_sw_params_t</a> *swparams)
{
<span class="keywordtype">int</span> err;
<span class="comment">/* get the current swparams */</span>
err = <a name="a15"></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 playback: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* start the transfer when the buffer is full */</span>
err = <a name="a16"></a><a class="code" href="group___p_c_m___s_w___params.html#a12">snd_pcm_sw_params_set_start_threshold</a>(handle, swparams, buffer_size);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set start threshold mode for playback: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* allow the transfer when at least period_size samples can be processed */</span>
err = <a name="a17"></a><a class="code" href="group___p_c_m___s_w___params.html#a8">snd_pcm_sw_params_set_avail_min</a>(handle, swparams, period_size);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set avail min for playback: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* align all transfers to 1 sample */</span>
err = <a name="a18"></a><a class="code" href="group___p_c_m___s_w___params.html#a10">snd_pcm_sw_params_set_xfer_align</a>(handle, swparams, 1);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set transfer align for playback: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* write the parameters to the playback device */</span>
err = <a name="a19"></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 playback: %s\n"</span>, <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="comment">/*</span>
<span class="comment"> * Underrun and suspend recovery</span>
<span class="comment"> */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> xrun_recovery(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle, <span class="keywordtype">int</span> err)
{
<span class="keywordflow">if</span> (err == -EPIPE) { <span class="comment">/* under-run */</span>
err = <a name="a20"></a><a class="code" href="group___p_c_m.html#a43">snd_pcm_prepare</a>(handle);
<span class="keywordflow">if</span> (err < 0)
printf(<span class="stringliteral">"Can't recovery from underrun, prepare failed: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> 0;
} <span class="keywordflow">else</span> <span class="keywordflow">if</span> (err == -ESTRPIPE) {
<span class="keywordflow">while</span> ((err = <a name="a21"></a><a class="code" href="group___p_c_m.html#a53">snd_pcm_resume</a>(handle)) == -EAGAIN)
sleep(1); <span class="comment">/* wait until the suspend flag is released */</span>
<span class="keywordflow">if</span> (err < 0) {
err = <a class="code" href="group___p_c_m.html#a43">snd_pcm_prepare</a>(handle);
<span class="keywordflow">if</span> (err < 0)
printf(<span class="stringliteral">"Can't recovery from suspend, prepare failed: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
}
<span class="keywordflow">return</span> 0;
}
<span class="keywordflow">return</span> err;
}
<span class="comment">/*</span>
<span class="comment"> * Transfer method - write only</span>
<span class="comment"> */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> write_loop(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples,
<a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a> *areas)
{
<span class="keywordtype">double</span> phase = 0;
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *ptr;
<span class="keywordtype">int</span> err, cptr;
<span class="keywordflow">while</span> (1) {
generate_sine(areas, 0, period_size, &phase);
ptr = samples;
cptr = period_size;
<span class="keywordflow">while</span> (cptr > 0) {
err = <a name="a22"></a><a class="code" href="group___p_c_m.html#a56">snd_pcm_writei</a>(handle, ptr, cptr);
<span class="keywordflow">if</span> (err == -EAGAIN)
<span class="keywordflow">continue</span>;
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> (xrun_recovery(handle, err) < 0) {
printf(<span class="stringliteral">"Write error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="keywordflow">break</span>; <span class="comment">/* skip one period */</span>
}
ptr += err * channels;
cptr -= err;
}
}
}
<span class="comment">/*</span>
<span class="comment"> * Transfer method - write and wait for room in buffer using poll</span>
<span class="comment"> */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> wait_for_poll(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle, <span class="keyword">struct</span> pollfd *ufds, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> count)
{
<span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> revents;
<span class="keywordflow">while</span> (1) {
poll(ufds, count, -1);
<a name="a23"></a><a class="code" href="group___p_c_m.html#a33">snd_pcm_poll_descriptors_revents</a>(handle, ufds, count, &revents);
<span class="keywordflow">if</span> (revents & POLLERR)
<span class="keywordflow">return</span> -EIO;
<span class="keywordflow">if</span> (revents & POLLOUT)
<span class="keywordflow">return</span> 0;
}
}
<span class="keyword">static</span> <span class="keywordtype">int</span> write_and_poll_loop(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples,
<a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a> *areas)
{
<span class="keyword">struct </span>pollfd *ufds;
<span class="keywordtype">double</span> phase = 0;
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *ptr;
<span class="keywordtype">int</span> err, count, cptr, init;
count = <a name="a24"></a><a class="code" href="group___p_c_m.html#a31">snd_pcm_poll_descriptors_count</a> (handle);
<span class="keywordflow">if</span> (count <= 0) {
printf(<span class="stringliteral">"Invalid poll descriptors count\n"</span>);
<span class="keywordflow">return</span> count;
}
ufds = malloc(<span class="keyword">sizeof</span>(<span class="keyword">struct</span> pollfd) * count);
<span class="keywordflow">if</span> (ufds == NULL) {
printf(<span class="stringliteral">"No enough memory\n"</span>);
<span class="keywordflow">return</span> err;;
}
<span class="keywordflow">if</span> ((err = <a name="a25"></a><a class="code" href="group___p_c_m.html#a32">snd_pcm_poll_descriptors</a>(handle, ufds, count)) < 0) {
printf(<span class="stringliteral">"Unable to obtain poll descriptors for playback: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
init = 1;
<span class="keywordflow">while</span> (1) {
<span class="keywordflow">if</span> (!init) {
err = wait_for_poll(handle, ufds, count);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> (<a name="a26"></a><a class="code" href="group___p_c_m.html#a50">snd_pcm_state</a>(handle) == <a class="code" href="group___p_c_m.html#a72a111">SND_PCM_STATE_XRUN</a> ||
<a class="code" href="group___p_c_m.html#a50">snd_pcm_state</a>(handle) == <a class="code" href="group___p_c_m.html#a72a114">SND_PCM_STATE_SUSPENDED</a>) {
err = <a class="code" href="group___p_c_m.html#a50">snd_pcm_state</a>(handle) == <a class="code" href="group___p_c_m.html#a72a111">SND_PCM_STATE_XRUN</a> ? -EPIPE : -ESTRPIPE;
<span class="keywordflow">if</span> (xrun_recovery(handle, err) < 0) {
printf(<span class="stringliteral">"Write error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
init = 1;
} <span class="keywordflow">else</span> {
printf(<span class="stringliteral">"Wait for poll failed\n"</span>);
<span class="keywordflow">return</span> err;
}
}
}
generate_sine(areas, 0, period_size, &phase);
ptr = samples;
cptr = period_size;
<span class="keywordflow">while</span> (cptr > 0) {
err = <a class="code" href="group___p_c_m.html#a56">snd_pcm_writei</a>(handle, ptr, cptr);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> (xrun_recovery(handle, err) < 0) {
printf(<span class="stringliteral">"Write error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
init = 1;
<span class="keywordflow">break</span>; <span class="comment">/* skip one period */</span>
}
<span class="keywordflow">if</span> (<a class="code" href="group___p_c_m.html#a50">snd_pcm_state</a>(handle) == <a class="code" href="group___p_c_m.html#a72a110">SND_PCM_STATE_RUNNING</a>)
init = 0;
ptr += err * channels;
cptr -= err;
<span class="keywordflow">if</span> (cptr == 0)
<span class="keywordflow">break</span>;
<span class="comment">/* it is possible, that the initial buffer cannot store */</span>
<span class="comment">/* all data from the last period, so wait awhile */</span>
err = wait_for_poll(handle, ufds, count);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> (<a class="code" href="group___p_c_m.html#a50">snd_pcm_state</a>(handle) == <a class="code" href="group___p_c_m.html#a72a111">SND_PCM_STATE_XRUN</a> ||
<a class="code" href="group___p_c_m.html#a50">snd_pcm_state</a>(handle) == <a class="code" href="group___p_c_m.html#a72a114">SND_PCM_STATE_SUSPENDED</a>) {
err = <a class="code" href="group___p_c_m.html#a50">snd_pcm_state</a>(handle) == <a class="code" href="group___p_c_m.html#a72a111">SND_PCM_STATE_XRUN</a> ? -EPIPE : -ESTRPIPE;
<span class="keywordflow">if</span> (xrun_recovery(handle, err) < 0) {
printf(<span class="stringliteral">"Write error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
init = 1;
} <span class="keywordflow">else</span> {
printf(<span class="stringliteral">"Wait for poll failed\n"</span>);
<span class="keywordflow">return</span> err;
}
}
}
}
}
<span class="comment">/*</span>
<span class="comment"> * Transfer method - asynchronous notification</span>
<span class="comment"> */</span>
<span class="keyword">struct </span>async_private_data {
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples;
<a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a> *areas;
<span class="keywordtype">double</span> phase;
};
<span class="keyword">static</span> <span class="keywordtype">void</span> async_callback(<a class="code" href="group___global.html#a0">snd_async_handler_t</a> *ahandler)
{
<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle = <a name="a27"></a><a class="code" href="group___p_c_m.html#a36">snd_async_handler_get_pcm</a>(ahandler);
<span class="keyword">struct </span>async_private_data *data = <a name="a28"></a><a class="code" href="group___global.html#a9">snd_async_handler_get_callback_private</a>(ahandler);
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples = data->samples;
<a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a> *areas = data->areas;
<a class="code" href="group___p_c_m.html#a18">snd_pcm_sframes_t</a> avail;
<span class="keywordtype">int</span> err;
avail = <a name="a29"></a><a class="code" href="group___p_c_m.html#a54">snd_pcm_avail_update</a>(handle);
<span class="keywordflow">while</span> (avail >= period_size) {
generate_sine(areas, 0, period_size, &data->phase);
err = <a class="code" href="group___p_c_m.html#a56">snd_pcm_writei</a>(handle, samples, period_size);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Initial write error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="keywordflow">if</span> (err != period_size) {
printf(<span class="stringliteral">"Initial write error: written %i expected %li\n"</span>, err, period_size);
exit(EXIT_FAILURE);
}
avail = <a class="code" href="group___p_c_m.html#a54">snd_pcm_avail_update</a>(handle);
}
}
<span class="keyword">static</span> <span class="keywordtype">int</span> async_loop(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples,
<a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a> *areas)
{
<span class="keyword">struct </span>async_private_data data;
<a class="code" href="group___global.html#a0">snd_async_handler_t</a> *ahandler;
<span class="keywordtype">int</span> err, count;
data.samples = samples;
data.areas = areas;
data.phase = 0;
err = <a name="a30"></a><a class="code" href="group___p_c_m.html#a35">snd_async_add_pcm_handler</a>(&ahandler, handle, async_callback, &data);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to register async handler\n"</span>);
exit(EXIT_FAILURE);
}
<span class="keywordflow">for</span> (count = 0; count < 2; count++) {
generate_sine(areas, 0, period_size, &data.phase);
err = <a class="code" href="group___p_c_m.html#a56">snd_pcm_writei</a>(handle, samples, period_size);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Initial write error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="keywordflow">if</span> (err != period_size) {
printf(<span class="stringliteral">"Initial write error: written %i expected %li\n"</span>, err, period_size);
exit(EXIT_FAILURE);
}
}
err = <a name="a31"></a><a class="code" href="group___p_c_m.html#a46">snd_pcm_start</a>(handle);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Start error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="comment">/* because all other work is done in the signal handler,</span>
<span class="comment"> suspend the process */</span>
<span class="keywordflow">while</span> (1) {
sleep(1);
}
}
<span class="comment">/*</span>
<span class="comment"> * Transfer method - direct write only</span>
<span class="comment"> */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> direct_loop(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples,
<a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a> *areas)
{
<span class="keywordtype">double</span> phase = 0;
<span class="keyword">const</span> <a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a> *my_areas;
<a class="code" href="group___p_c_m.html#a17">snd_pcm_uframes_t</a> offset, frames, size;
<a class="code" href="group___p_c_m.html#a18">snd_pcm_sframes_t</a> avail, commitres;
<a class="code" href="group___p_c_m.html#a13">snd_pcm_state_t</a> state;
<span class="keywordtype">int</span> err, first = 1;
<span class="keywordflow">while</span> (1) {
state = <a class="code" href="group___p_c_m.html#a50">snd_pcm_state</a>(handle);
<span class="keywordflow">if</span> (state == <a class="code" href="group___p_c_m.html#a72a111">SND_PCM_STATE_XRUN</a>) {
err = xrun_recovery(handle, -EPIPE);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"XRUN recovery failed: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
first = 1;
} <span class="keywordflow">else</span> <span class="keywordflow">if</span> (state == <a class="code" href="group___p_c_m.html#a72a114">SND_PCM_STATE_SUSPENDED</a>) {
err = xrun_recovery(handle, -ESTRPIPE);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"SUSPEND recovery failed: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
}
avail = <a class="code" href="group___p_c_m.html#a54">snd_pcm_avail_update</a>(handle);
<span class="keywordflow">if</span> (avail < 0) {
err = xrun_recovery(handle, avail);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"avail update failed: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
first = 1;
<span class="keywordflow">continue</span>;
}
<span class="keywordflow">if</span> (avail < period_size) {
<span class="keywordflow">if</span> (first) {
first = 0;
err = <a class="code" href="group___p_c_m.html#a46">snd_pcm_start</a>(handle);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Start error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
} <span class="keywordflow">else</span> {
err = <a name="a32"></a><a class="code" href="group___p_c_m.html#a60">snd_pcm_wait</a>(handle, -1);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> ((err = xrun_recovery(handle, err)) < 0) {
printf(<span class="stringliteral">"snd_pcm_wait error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
first = 1;
}
}
<span class="keywordflow">continue</span>;
}
size = period_size;
<span class="keywordflow">while</span> (size > 0) {
frames = size;
err = <a name="a33"></a><a class="code" href="group___p_c_m___direct.html#a0">snd_pcm_mmap_begin</a>(handle, &my_areas, &offset, &frames);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> ((err = xrun_recovery(handle, err)) < 0) {
printf(<span class="stringliteral">"MMAP begin avail error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
first = 1;
}
generate_sine(my_areas, offset, frames, &phase);
commitres = <a name="a34"></a><a class="code" href="group___p_c_m___direct.html#a1">snd_pcm_mmap_commit</a>(handle, offset, frames);
<span class="keywordflow">if</span> (commitres < 0 || commitres != frames) {
<span class="keywordflow">if</span> ((err = xrun_recovery(handle, commitres >= 0 ? -EPIPE : commitres)) < 0) {
printf(<span class="stringliteral">"MMAP commit error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
first = 1;
}
size -= frames;
}
}
}
<span class="comment">/*</span>
<span class="comment"> * Transfer method - direct write only using mmap_write functions</span>
<span class="comment"> */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> direct_write_loop(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples,
<a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a> *areas)
{
<span class="keywordtype">double</span> phase = 0;
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *ptr;
<span class="keywordtype">int</span> err, cptr;
<span class="keywordflow">while</span> (1) {
generate_sine(areas, 0, period_size, &phase);
ptr = samples;
cptr = period_size;
<span class="keywordflow">while</span> (cptr > 0) {
err = <a name="a35"></a><a class="code" href="group___p_c_m___direct.html#a2">snd_pcm_mmap_writei</a>(handle, ptr, cptr);
<span class="keywordflow">if</span> (err == -EAGAIN)
<span class="keywordflow">continue</span>;
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> (xrun_recovery(handle, err) < 0) {
printf(<span class="stringliteral">"Write error: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="keywordflow">break</span>; <span class="comment">/* skip one period */</span>
}
ptr += err * channels;
cptr -= err;
}
}
}
<span class="comment">/*</span>
<span class="comment"> *</span>
<span class="comment"> */</span>
<span class="keyword">struct </span>transfer_method {
<span class="keyword">const</span> <span class="keywordtype">char</span> *name;
<a class="code" href="group___p_c_m.html#a10">snd_pcm_access_t</a> access;
int (*transfer_loop)(<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples,
<a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a> *areas);
};
<span class="keyword">static</span> <span class="keyword">struct </span>transfer_method transfer_methods[] = {
{ <span class="stringliteral">"write"</span>, <a class="code" href="group___p_c_m.html#a69a53">SND_PCM_ACCESS_RW_INTERLEAVED</a>, write_loop },
{ <span class="stringliteral">"write_and_poll"</span>, <a class="code" href="group___p_c_m.html#a69a53">SND_PCM_ACCESS_RW_INTERLEAVED</a>, write_and_poll_loop },
{ <span class="stringliteral">"async"</span>, <a class="code" href="group___p_c_m.html#a69a53">SND_PCM_ACCESS_RW_INTERLEAVED</a>, async_loop },
{ <span class="stringliteral">"direct_interleaved"</span>, <a class="code" href="group___p_c_m.html#a69a50">SND_PCM_ACCESS_MMAP_INTERLEAVED</a>, direct_loop },
{ <span class="stringliteral">"direct_noninterleaved"</span>, <a class="code" href="group___p_c_m.html#a69a51">SND_PCM_ACCESS_MMAP_NONINTERLEAVED</a>, direct_loop },
{ <span class="stringliteral">"direct_write"</span>, <a class="code" href="group___p_c_m.html#a69a50">SND_PCM_ACCESS_MMAP_INTERLEAVED</a>, direct_write_loop },
{ NULL, <a class="code" href="group___p_c_m.html#a69a53">SND_PCM_ACCESS_RW_INTERLEAVED</a>, NULL }
};
<span class="keyword">static</span> <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">-D,--device playback device</span>
<span class="stringliteral">-r,--rate stream rate in Hz</span>
<span class="stringliteral">-c,--channels count of channels in stream</span>
<span class="stringliteral">-f,--frequency sine wave frequency in Hz</span>
<span class="stringliteral">-b,--buffer ring buffer size in us</span>
<span class="stringliteral">-p,--period period size in us</span>
<span class="stringliteral">-m,--method transfer method</span>
<span class="stringliteral"></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="a36"></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"</span>);
printf(<span class="stringliteral">"Recognized transfer methods are:"</span>);
<span class="keywordflow">for</span> (k = 0; transfer_methods[k].name; k++)
printf(<span class="stringliteral">" %s"</span>, transfer_methods[k].name);
printf(<span class="stringliteral">"\n"</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">"device"</span>, 1, NULL, <span class="charliteral">'D'</span>},
{<span class="stringliteral">"rate"</span>, 1, NULL, <span class="charliteral">'r'</span>},
{<span class="stringliteral">"channels"</span>, 1, NULL, <span class="charliteral">'c'</span>},
{<span class="stringliteral">"frequency"</span>, 1, NULL, <span class="charliteral">'f'</span>},
{<span class="stringliteral">"buffer"</span>, 1, NULL, <span class="charliteral">'b'</span>},
{<span class="stringliteral">"period"</span>, 1, NULL, <span class="charliteral">'p'</span>},
{<span class="stringliteral">"method"</span>, 1, NULL, <span class="charliteral">'m'</span>},
{NULL, 0, NULL, 0},
};
<a class="code" href="group___p_c_m.html#a20">snd_pcm_t</a> *handle;
<span class="keywordtype">int</span> err, morehelp;
<a class="code" href="group___p_c_m.html#a1">snd_pcm_hw_params_t</a> *hwparams;
<a class="code" href="group___p_c_m.html#a2">snd_pcm_sw_params_t</a> *swparams;
<span class="keywordtype">int</span> method = 0;
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples;
<span class="keywordtype">int</span> chn;
<a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a> *areas;
<a name="a37"></a><a class="code" href="group___p_c_m___h_w___params.html#a186">snd_pcm_hw_params_alloca</a>(&hwparams);
<a name="a38"></a><a class="code" href="group___p_c_m___s_w___params.html#a20">snd_pcm_sw_params_alloca</a>(&swparams);
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">"hD:r:c:f:b:p:m:"</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">'D'</span>:
device = strdup(optarg);
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'r'</span>:
rate = atoi(optarg);
rate = rate < 4000 ? 4000 : rate;
rate = rate > 196000 ? 196000 : rate;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'c'</span>:
channels = atoi(optarg);
channels = channels < 1 ? 1 : channels;
channels = channels > 1024 ? 1024 : channels;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'f'</span>:
freq = atoi(optarg);
freq = freq < 50 ? 50 : freq;
freq = freq > 5000 ? 5000 : freq;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'b'</span>:
buffer_time = atoi(optarg);
buffer_time = buffer_time < 1000 ? 1000 : buffer_time;
buffer_time = buffer_time > 1000000 ? 1000000 : buffer_time;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'p'</span>:
period_time = atoi(optarg);
period_time = period_time < 1000 ? 1000 : period_time;
period_time = period_time > 1000000 ? 1000000 : period_time;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'m'</span>:
<span class="keywordflow">for</span> (method = 0; transfer_methods[method].name; method++)
<span class="keywordflow">if</span> (!strcasecmp(transfer_methods[method].name, optarg))
<span class="keywordflow">break</span>;
<span class="keywordflow">if</span> (transfer_methods[method].name == NULL)
method = 0;
<span class="keywordflow">break</span>;
}
}
<span class="keywordflow">if</span> (morehelp) {
help();
<span class="keywordflow">return</span> 0;
}
err = <a name="a39"></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;
}
printf(<span class="stringliteral">"Playback device is %s\n"</span>, device);
printf(<span class="stringliteral">"Stream parameters are %iHz, %s, %i channels\n"</span>, rate, <a class="code" href="group___p_c_m___description.html#a2">snd_pcm_format_name</a>(format), channels);
printf(<span class="stringliteral">"Sine wave rate is %.4fHz\n"</span>, freq);
printf(<span class="stringliteral">"Using transfer method: %s\n"</span>, transfer_methods[method].name);
<span class="keywordflow">if</span> ((err = <a name="a40"></a><a class="code" href="group___p_c_m.html#a25">snd_pcm_open</a>(&handle, device, <a class="code" href="group___p_c_m.html#a68a47">SND_PCM_STREAM_PLAYBACK</a>, 0)) < 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 = set_hwparams(handle, hwparams, transfer_methods[method].access)) < 0) {
printf(<span class="stringliteral">"Setting of hwparams failed: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="keywordflow">if</span> ((err = set_swparams(handle, swparams)) < 0) {
printf(<span class="stringliteral">"Setting of swparams failed: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
samples = malloc((period_size * channels * <a name="a41"></a><a class="code" href="group___p_c_m___helpers.html#a7">snd_pcm_format_width</a>(format)) / 8);
<span class="keywordflow">if</span> (samples == NULL) {
printf(<span class="stringliteral">"No enough memory\n"</span>);
exit(EXIT_FAILURE);
}
areas = calloc(channels, <span class="keyword">sizeof</span>(<a class="code" href="struct__snd__pcm__channel__area.html">snd_pcm_channel_area_t</a>));
<span class="keywordflow">if</span> (areas == NULL) {
printf(<span class="stringliteral">"No enough memory\n"</span>);
exit(EXIT_FAILURE);
}
<span class="keywordflow">for</span> (chn = 0; chn < channels; chn++) {
areas[chn].<a class="code" href="struct__snd__pcm__channel__area.html#m0">addr</a> = samples;
areas[chn].<a class="code" href="struct__snd__pcm__channel__area.html#m1">first</a> = chn * 16;
areas[chn].<a class="code" href="struct__snd__pcm__channel__area.html#m2">step</a> = channels * 16;
}
err = transfer_methods[method].transfer_loop(handle, samples, areas);
<span class="keywordflow">if</span> (err < 0)
printf(<span class="stringliteral">"Transfer failed: %s\n"</span>, <a class="code" href="group___error.html#a2">snd_strerror</a>(err));
free(areas);
free(samples);
<a name="a42"></a><a class="code" href="group___p_c_m.html#a27">snd_pcm_close</a>(handle);
<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
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