mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-23 20:58:55 -05:00
93 lines
3.2 KiB
HTML
93 lines
3.2 KiB
HTML
|
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
|
||
|
|
<html>
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
|
||
|
|
<meta name="GENERATOR" content="Mozilla/4.79 [en] (Windows NT 5.0; U) [Netscape]">
|
||
|
|
<meta name="Author" content="Phil Burk">
|
||
|
|
<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.">
|
||
|
|
<meta name="KeyWords" content="audio, tutorial, library, portable, open-source, DirectSound,sound, music, JSyn, synthesis,">
|
||
|
|
<title>PortAudio Tutorial</title>
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
|
||
|
|
<center><table COLS=1 WIDTH="100%" BGCOLOR="#FADA7A" >
|
||
|
|
<tr>
|
||
|
|
<td>
|
||
|
|
<center>
|
||
|
|
<h1>
|
||
|
|
PortAudio Tutorial</h1></center>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</table></center>
|
||
|
|
|
||
|
|
<h2>
|
||
|
|
Overview of PortAudio</h2>
|
||
|
|
|
||
|
|
<blockquote>PortAudio is a library that provides streaming audio input
|
||
|
|
and output. It is a cross-platform API (Application Programming Interface)
|
||
|
|
that works on Windows, Macintosh, Unix running OSS, SGI, BeOS, and perhaps
|
||
|
|
other platforms by the time you read this. This means that you can write
|
||
|
|
a simple 'C' program to process or generate an audio signal, and that program
|
||
|
|
can run on several different types of computer just by recompiling the
|
||
|
|
source code.
|
||
|
|
<p>Here are the steps to writing a PortAudio application:
|
||
|
|
<ol>
|
||
|
|
<li>
|
||
|
|
Write a callback function that will be called by PortAudio when audio processing
|
||
|
|
is needed.</li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
Initialize the PA library and open a stream for audio I/O.</li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
Start the stream. Your callback function will be now be called repeatedly
|
||
|
|
by PA in the background.</li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
In your callback you can read audio data from the inputBuffer and/or write
|
||
|
|
data to the outputBuffer.</li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
Stop the stream by returning 1 from your callback, or by calling a stop
|
||
|
|
function.</li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
Close the stream and terminate the library.</li>
|
||
|
|
</ol>
|
||
|
|
</blockquote>
|
||
|
|
|
||
|
|
<blockquote>There is also <a href="pa_tut_rw.html">another interface</a>
|
||
|
|
provided that allows you to generate audio in the foreground. You then
|
||
|
|
simply write data to the stream and the tool will not return until it is
|
||
|
|
ready to accept more data. This interface is simpler to use but is usually
|
||
|
|
not preferred for large applications because it requires that you launch
|
||
|
|
a thread to perform the synthesis. Launching a thread may be difficult
|
||
|
|
on non-multi-tasking systems such as the Macintosh prior to MacOS X.
|
||
|
|
<p>Let's continue by building a simple application that will play a sawtooth
|
||
|
|
wave.
|
||
|
|
<p>Please select the page for the specific implementation you would like
|
||
|
|
to use:
|
||
|
|
<ul>
|
||
|
|
<li>
|
||
|
|
<a href="pa_tut_pc.html">Windows (WMME or DirectSound)</a></li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
<a href="pa_tut_mac.html">Macintosh SoundManager for OS 7,8,9</a></li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
<a href="pa_tut_mac_osx.html">Macintosh CoreAudio for OS X</a></li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
<a href="pa_tut_asio.html">ASIO on Windows or Macintosh</a></li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
<a href="pa_tut_oss.html">Unix OSS</a></li>
|
||
|
|
</ul>
|
||
|
|
or continue with the <a href="pa_tut_callback.html">next page of the programming
|
||
|
|
tutorial</a>.</blockquote>
|
||
|
|
<font size=+2><a href="http://www.portaudio.com/">home</a> |
|
||
|
|
<a href="pa_tutorial.html">contents</a>
|
||
|
|
| <a href="pa_tutorial.html">previous</a></font>
|
||
|
|
</body>
|
||
|
|
</html>
|