| 1 | <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> |
| 2 | <html> |
| 3 | <head> |
| 4 | <link rel="STYLESHEET" href="lib.css" type='text/css' /> |
| 5 | <link rel="SHORTCUT ICON" href="../icons/pyfav.png" type="image/png" /> |
| 6 | <link rel='start' href='../index.html' title='Python Documentation Index' /> |
| 7 | <link rel="first" href="lib.html" title='Python Library Reference' /> |
| 8 | <link rel='contents' href='contents.html' title="Contents" /> |
| 9 | <link rel='index' href='genindex.html' title='Index' /> |
| 10 | <link rel='last' href='about.html' title='About this document...' /> |
| 11 | <link rel='help' href='about.html' title='About this document...' /> |
| 12 | <link rel="prev" href="module-sndhdr.html" /> |
| 13 | <link rel="parent" href="mmedia.html" /> |
| 14 | <link rel="next" href="ossaudio-device-objects.html" /> |
| 15 | <meta name='aesop' content='information' /> |
| 16 | <title>14.11 ossaudiodev -- Access to OSS-compatible audio devices</title> |
| 17 | </head> |
| 18 | <body> |
| 19 | <DIV CLASS="navigation"> |
| 20 | <div id='top-navigation-panel' xml:id='top-navigation-panel'> |
| 21 | <table align="center" width="100%" cellpadding="0" cellspacing="2"> |
| 22 | <tr> |
| 23 | <td class='online-navigation'><a rel="prev" title="14.10 sndhdr " |
| 24 | href="module-sndhdr.html"><img src='../icons/previous.png' |
| 25 | border='0' height='32' alt='Previous Page' width='32' /></A></td> |
| 26 | <td class='online-navigation'><a rel="parent" title="14. Multimedia Services" |
| 27 | href="mmedia.html"><img src='../icons/up.png' |
| 28 | border='0' height='32' alt='Up One Level' width='32' /></A></td> |
| 29 | <td class='online-navigation'><a rel="next" title="14.11.1 Audio Device Objects" |
| 30 | href="ossaudio-device-objects.html"><img src='../icons/next.png' |
| 31 | border='0' height='32' alt='Next Page' width='32' /></A></td> |
| 32 | <td align="center" width="100%">Python Library Reference</td> |
| 33 | <td class='online-navigation'><a rel="contents" title="Table of Contents" |
| 34 | href="contents.html"><img src='../icons/contents.png' |
| 35 | border='0' height='32' alt='Contents' width='32' /></A></td> |
| 36 | <td class='online-navigation'><a href="modindex.html" title="Module Index"><img src='../icons/modules.png' |
| 37 | border='0' height='32' alt='Module Index' width='32' /></a></td> |
| 38 | <td class='online-navigation'><a rel="index" title="Index" |
| 39 | href="genindex.html"><img src='../icons/index.png' |
| 40 | border='0' height='32' alt='Index' width='32' /></A></td> |
| 41 | </tr></table> |
| 42 | <div class='online-navigation'> |
| 43 | <b class="navlabel">Previous:</b> |
| 44 | <a class="sectref" rel="prev" href="module-sndhdr.html">14.10 sndhdr </A> |
| 45 | <b class="navlabel">Up:</b> |
| 46 | <a class="sectref" rel="parent" href="mmedia.html">14. Multimedia Services</A> |
| 47 | <b class="navlabel">Next:</b> |
| 48 | <a class="sectref" rel="next" href="ossaudio-device-objects.html">14.11.1 Audio Device Objects</A> |
| 49 | </div> |
| 50 | <hr /></div> |
| 51 | </DIV> |
| 52 | <!--End of Navigation Panel--> |
| 53 | |
| 54 | <H1><A NAME="SECTION00161100000000000000000"> |
| 55 | 14.11 <tt class="module">ossaudiodev</tt> -- |
| 56 | Access to OSS-compatible audio devices</A> |
| 57 | </H1> |
| 58 | |
| 59 | <P> |
| 60 | <A NAME="module-ossaudiodev"></A> |
| 61 | <p class="availability">Availability: <span |
| 62 | class="platform">Linux, FreeBSD</span>.</p> |
| 63 | |
| 64 | <P> |
| 65 | |
| 66 | <span class="versionnote">New in version 2.3.</span> |
| 67 | |
| 68 | <P> |
| 69 | This module allows you to access the OSS (Open Sound System) audio |
| 70 | interface. OSS is available for a wide range of open-source and |
| 71 | commercial Unices, and is the standard audio interface for Linux and |
| 72 | recent versions of FreeBSD. |
| 73 | |
| 74 | <P> |
| 75 | <div class="seealso"> |
| 76 | <p class="heading">See Also:</p> |
| 77 | |
| 78 | <dl compact="compact" class="seetitle"> |
| 79 | <dt><em class="citetitle"><a href="http://www.opensound.com/pguide/oss.pdf" |
| 80 | >Open Sound System Programmer's Guide</a></em></dt> |
| 81 | <dd>the official |
| 82 | documentation for the OSS C API</dd> |
| 83 | </dl> |
| 84 | <div class="seetext"><p>The module defines a large number of constants supplied by |
| 85 | the OSS device driver; see <code><sys/soundcard.h></code> on either |
| 86 | Linux or FreeBSD for a listing .</p></div> |
| 87 | </div> |
| 88 | |
| 89 | <P> |
| 90 | <tt class="module">ossaudiodev</tt> defines the following variables and functions: |
| 91 | |
| 92 | <P> |
| 93 | <dl><dt><b><span class="typelabel">exception</span> <tt id='l2h-4770' xml:id='l2h-4770' class="exception">OSSAudioError</tt></b></dt> |
| 94 | <dd> |
| 95 | This exception is raised on certain errors. The argument is a string |
| 96 | describing what went wrong. |
| 97 | |
| 98 | <P> |
| 99 | (If <tt class="module">ossaudiodev</tt> receives an error from a system call such as |
| 100 | <tt class="cfunction">open()</tt>, <tt class="cfunction">write()</tt>, or <tt class="cfunction">ioctl()</tt>, it |
| 101 | raises <tt class="exception">IOError</tt>. Errors detected directly by |
| 102 | <tt class="module">ossaudiodev</tt> result in <tt class="exception">OSSAudioError</tt>.) |
| 103 | |
| 104 | <P> |
| 105 | (For backwards compatibility, the exception class is also available as |
| 106 | <code>ossaudiodev.error</code>.) |
| 107 | </dd></dl> |
| 108 | |
| 109 | <P> |
| 110 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> |
| 111 | <td><nobr><b><tt id='l2h-4771' xml:id='l2h-4771' class="function">open</tt></b>(</nobr></td> |
| 112 | <td><var></var><big>[</big><var>device, </var><big>]</big><var>mode</var>)</td></tr></table></dt> |
| 113 | <dd> |
| 114 | Open an audio device and return an OSS audio device object. This |
| 115 | object supports many file-like methods, such as <tt class="method">read()</tt>, |
| 116 | <tt class="method">write()</tt>, and <tt class="method">fileno()</tt> (although there are subtle |
| 117 | differences between conventional Unix read/write semantics and those of |
| 118 | OSS audio devices). It also supports a number of audio-specific |
| 119 | methods; see below for the complete list of methods. |
| 120 | |
| 121 | <P> |
| 122 | <var>device</var> is the audio device filename to use. If it is not |
| 123 | specified, this module first looks in the environment variable |
| 124 | <a class="envvar" id='l2h-4773' xml:id='l2h-4773'>AUDIODEV</a> for a device to use. If not found, it falls back to |
| 125 | <span class="file">/dev/dsp</span>. |
| 126 | |
| 127 | <P> |
| 128 | <var>mode</var> is one of <code>'r'</code> for read-only (record) access, |
| 129 | <code>'w'</code> for write-only (playback) access and <code>'rw'</code> for both. |
| 130 | Since many sound cards only allow one process to have the recorder or |
| 131 | player open at a time, it is a good idea to open the device only for the |
| 132 | activity needed. Further, some sound cards are half-duplex: they can be |
| 133 | opened for reading or writing, but not both at once. |
| 134 | |
| 135 | <P> |
| 136 | Note the unusual calling syntax: the <em>first</em> argument is optional, |
| 137 | and the second is required. This is a historical artifact for |
| 138 | compatibility with the older <tt class="module">linuxaudiodev</tt> module which |
| 139 | <tt class="module">ossaudiodev</tt> supersedes. </dl> |
| 140 | |
| 141 | <P> |
| 142 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> |
| 143 | <td><nobr><b><tt id='l2h-4772' xml:id='l2h-4772' class="function">openmixer</tt></b>(</nobr></td> |
| 144 | <td><var></var><big>[</big><var>device</var><big>]</big><var></var>)</td></tr></table></dt> |
| 145 | <dd> |
| 146 | Open a mixer device and return an OSS mixer device object. |
| 147 | <var>device</var> is the mixer device filename to use. If it is |
| 148 | not specified, this module first looks in the environment variable |
| 149 | <a class="envvar" id='l2h-4774' xml:id='l2h-4774'>MIXERDEV</a> for a device to use. If not found, it falls back to |
| 150 | <span class="file">/dev/mixer</span>. |
| 151 | |
| 152 | <P> |
| 153 | </dl> |
| 154 | |
| 155 | <P> |
| 156 | |
| 157 | <p><br /></p><hr class='online-navigation' /> |
| 158 | <div class='online-navigation'> |
| 159 | <!--Table of Child-Links--> |
| 160 | <A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a> |
| 161 | |
| 162 | <UL CLASS="ChildLinks"> |
| 163 | <LI><A href="ossaudio-device-objects.html">14.11.1 Audio Device Objects</a> |
| 164 | <LI><A href="mixer-device-objects.html">14.11.2 Mixer Device Objects</a> |
| 165 | </ul> |
| 166 | <!--End of Table of Child-Links--> |
| 167 | </div> |
| 168 | |
| 169 | <DIV CLASS="navigation"> |
| 170 | <div class='online-navigation'> |
| 171 | <p></p><hr /> |
| 172 | <table align="center" width="100%" cellpadding="0" cellspacing="2"> |
| 173 | <tr> |
| 174 | <td class='online-navigation'><a rel="prev" title="14.10 sndhdr " |
| 175 | href="module-sndhdr.html"><img src='../icons/previous.png' |
| 176 | border='0' height='32' alt='Previous Page' width='32' /></A></td> |
| 177 | <td class='online-navigation'><a rel="parent" title="14. Multimedia Services" |
| 178 | href="mmedia.html"><img src='../icons/up.png' |
| 179 | border='0' height='32' alt='Up One Level' width='32' /></A></td> |
| 180 | <td class='online-navigation'><a rel="next" title="14.11.1 Audio Device Objects" |
| 181 | href="ossaudio-device-objects.html"><img src='../icons/next.png' |
| 182 | border='0' height='32' alt='Next Page' width='32' /></A></td> |
| 183 | <td align="center" width="100%">Python Library Reference</td> |
| 184 | <td class='online-navigation'><a rel="contents" title="Table of Contents" |
| 185 | href="contents.html"><img src='../icons/contents.png' |
| 186 | border='0' height='32' alt='Contents' width='32' /></A></td> |
| 187 | <td class='online-navigation'><a href="modindex.html" title="Module Index"><img src='../icons/modules.png' |
| 188 | border='0' height='32' alt='Module Index' width='32' /></a></td> |
| 189 | <td class='online-navigation'><a rel="index" title="Index" |
| 190 | href="genindex.html"><img src='../icons/index.png' |
| 191 | border='0' height='32' alt='Index' width='32' /></A></td> |
| 192 | </tr></table> |
| 193 | <div class='online-navigation'> |
| 194 | <b class="navlabel">Previous:</b> |
| 195 | <a class="sectref" rel="prev" href="module-sndhdr.html">14.10 sndhdr </A> |
| 196 | <b class="navlabel">Up:</b> |
| 197 | <a class="sectref" rel="parent" href="mmedia.html">14. Multimedia Services</A> |
| 198 | <b class="navlabel">Next:</b> |
| 199 | <a class="sectref" rel="next" href="ossaudio-device-objects.html">14.11.1 Audio Device Objects</A> |
| 200 | </div> |
| 201 | </div> |
| 202 | <hr /> |
| 203 | <span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span> |
| 204 | </DIV> |
| 205 | <!--End of Navigation Panel--> |
| 206 | <ADDRESS> |
| 207 | See <i><a href="about.html">About this document...</a></i> for information on suggesting changes. |
| 208 | </ADDRESS> |
| 209 | </BODY> |
| 210 | </HTML> |