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57 lines
2.4 KiB
HTML
57 lines
2.4 KiB
HTML
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<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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<meta name="GENERATOR" content="Mozilla/4.73 [en]C-gatewaynet (Win98; U) [Netscape]">
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<meta name="Author" content="Phil Burk">
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<meta name="Description" content="Tutorial for PortAudio, a cross platform, open-source, audio I/O library.It provides a very simple API for recording and/or playing sound using a simple callback function.">
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<meta name="KeyWords" content="audio, tutorial, library, portable, open-source, DirectSound,sound, music, JSyn, synthesis,">
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<title>PortAudio Tutorial</title>
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</head>
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<body>
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<center><table COLS=1 WIDTH="100%" BGCOLOR="#FADA7A" >
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<tr>
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<td>
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<center>
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<h1>
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PortAudio Tutorial</h1></center>
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</td>
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</tr>
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</table></center>
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<h2>
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Starting and Stopping a Stream</h2>
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<blockquote>The stream will not start running until you call Pa_StartStream().
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Then it will start calling your callback function to perform the audio
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processing.
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<blockquote>
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<pre>err = Pa_StartStream( stream );
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if( err != paNoError ) goto error;</pre>
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</blockquote>
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At this point, audio is being generated. You can communicate to your callback
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routine through the data structure you passed in on the open call, or through
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global variables, or using other interprocess communication techniques.
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Please be aware that your callback function may be called at interrupt
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time when your foreground process is least expecting it. So avoid sharing
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complex data structures that are easily corrupted like double linked lists.
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<p>In many of the tests we simply sleep for a few seconds so we can hear
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the sound. This is easy to do with Pa_Sleep() which will sleep for some
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number of milliseconds. Do not rely on this function for accurate scheduling.
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it is mostly for writing examples.
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<blockquote>
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<pre>/* Sleep for several seconds. */
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Pa_Sleep(NUM_SECONDS*1000);</pre>
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</blockquote>
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When you are through, you can stop the stream from the foreground.
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<blockquote>
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<pre>err = Pa_StopStream( stream );
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if( err != paNoError ) goto error;</pre>
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</blockquote>
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You can also stop the stream by returning 1 from your custom callback function.</blockquote>
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<font size=+2><a href="http://www.portaudio.com/">home</a> | <a href="pa_tutorial.html">contents</a>
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| <a href="pa_tut_open.html">previous</a> | <a href="pa_tut_term.html">next</a></font>
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</body>
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</html>
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