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<h1><a class="anchor" id="recording">Recording </a></h1><p>Using <a class="el" href="classRtAudio.html" title="Realtime audio i/o C++ classes.">RtAudio</a> for audio input is almost identical to the way it is used for playback. Here's the blocking playback example rewritten for recording:</p>
<div class="fragment"><pre class="fragment"><span class="preprocessor">#include "<a class="code" href="RtAudio_8h.html">RtAudio.h</a>"</span>
<span class="preprocessor">#include <iostream></span>
<span class="preprocessor">#include <cstdlib></span>
<span class="preprocessor">#include <cstring></span>
<span class="keywordtype">int</span> record( <span class="keywordtype">void</span> *outputBuffer, <span class="keywordtype">void</span> *inputBuffer, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> nBufferFrames,
<span class="keywordtype">double</span> streamTime, <a class="code" href="RtAudio_8h.html#a80e306d363583da3b0a1b65d9b57c806" title="RtAudio stream status (over- or underflow) flags.">RtAudioStreamStatus</a> status, <span class="keywordtype">void</span> *userData )
{
<span class="keywordflow">if</span> ( status )
std::cout << <span class="stringliteral">"Stream overflow detected!"</span> << std::endl;
<span class="comment">// Do something with the data in the "inputBuffer" buffer.</span>
<span class="keywordflow">return</span> 0;
}
<span class="keywordtype">int</span> main()
{
<a class="code" href="classRtAudio.html" title="Realtime audio i/o C++ classes.">RtAudio</a> adc;
<span class="keywordflow">if</span> ( adc.<a class="code" href="classRtAudio.html#a747ce2d73803641bbb66d6e78092aa1a" title="A public function that queries for the number of audio devices available.">getDeviceCount</a>() < 1 ) {
std::cout << <span class="stringliteral">"\nNo audio devices found!\n"</span>;
exit( 0 );
}
<a class="code" href="structRtAudio_1_1StreamParameters.html" title="The structure for specifying input or ouput stream parameters.">RtAudio::StreamParameters</a> parameters;
parameters.<a class="code" href="structRtAudio_1_1StreamParameters.html#ab3c72bcf3ef12149ae9a4fb597cc5489">deviceId</a> = adc.<a class="code" href="classRtAudio.html#aad8b94edd3cd379ee300b125750ac6ce" title="A function that returns the index of the default input device.">getDefaultInputDevice</a>();
parameters.<a class="code" href="structRtAudio_1_1StreamParameters.html#a88a10091b6e284e21235cc6f25332ebd">nChannels</a> = 2;
parameters.<a class="code" href="structRtAudio_1_1StreamParameters.html#ad4b4503782653ec93c83328c46abe50c">firstChannel</a> = 0;
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> sampleRate = 44100;
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> bufferFrames = 256; <span class="comment">// 256 sample frames</span>
<span class="keywordflow">try</span> {
adc.<a class="code" href="classRtAudio.html#afacc99740fa4c5606fb35467cdea6da8" title="A public function for opening a stream with the specified parameters.">openStream</a>( NULL, &parameters, RTAUDIO_SINT16,
sampleRate, &bufferFrames, &record );
adc.<a class="code" href="classRtAudio.html#aec017a89629ccef66a90b60be22a2f80" title="A function that starts a stream.">startStream</a>();
}
<span class="keywordflow">catch</span> ( <a class="code" href="classRtError.html" title="Exception handling class for RtAudio &amp; RtMidi.">RtError</a>& e ) {
e.<a class="code" href="classRtError.html#a251dcdac396c998c91706dd2dd3b8bfc" title="Prints thrown error message to stderr.">printMessage</a>();
exit( 0 );
}
<span class="keywordtype">char</span> input;
std::cout << <span class="stringliteral">"\nRecording ... press <enter> to quit.\n"</span>;
std::cin.get( input );
<span class="keywordflow">try</span> {
<span class="comment">// Stop the stream</span>
adc.<a class="code" href="classRtAudio.html#af4c241ff86936ecc8108f0d9dfe3efdd" title="Stop a stream, allowing any samples remaining in the output queue to be played.">stopStream</a>();
}
<span class="keywordflow">catch</span> (<a class="code" href="classRtError.html" title="Exception handling class for RtAudio &amp; RtMidi.">RtError</a>& e) {
e.<a class="code" href="classRtError.html#a251dcdac396c998c91706dd2dd3b8bfc" title="Prints thrown error message to stderr.">printMessage</a>();
}
<span class="keywordflow">if</span> ( adc.<a class="code" href="classRtAudio.html#a3863e45ff81dbe97176de0ee7545917f" title="Returns true if a stream is open and false if not.">isStreamOpen</a>() ) adc.<a class="code" href="classRtAudio.html#a90d599002ad32cf250a4cb866f2cc93a" title="A function that closes a stream and frees any associated stream memory.">closeStream</a>();
<span class="keywordflow">return</span> 0;
}
</pre></div><p>In this example, we pass the address of the stream parameter structure as the second argument of the <a class="el" href="classRtAudio.html#afacc99740fa4c5606fb35467cdea6da8" title="A public function for opening a stream with the specified parameters.">RtAudio::openStream()</a> function and pass a NULL value for the output stream parameters. In this example, the <em>record()</em> callback function performs no specific operations. </p>
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