<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8"> <title>PulseAudio: Channel Maps</title> <link href="doxygen.css" rel="stylesheet" type="text/css"> <link href="tabs.css" rel="stylesheet" type="text/css"> </head><body> <!-- Generated by Doxygen 1.5.5 --> <div class="navigation" id="top"> <div class="tabs"> <ul> <li><a href="main.html"><span>Main Page</span></a></li> <li><a href="pages.html"><span>Related Pages</span></a></li> <li><a href="classes.html"><span>Data Structures</span></a></li> <li><a href="files.html"><span>Files</span></a></li> <li><a href="examples.html"><span>Examples</span></a></li> </ul> </div> </div> <div class="contents"> <h1><a class="anchor" name="channelmap">Channel Maps </a></h1><h2><a class="anchor" name="overv_sec"> Overview</a></h2> Channel maps provide a way to associate channels in a stream with a specific speaker position. This relieves applications of having to make sure their channel order is identical to the final output.<h2><a class="anchor" name="init_sec"> Initialisation</a></h2> A channel map consists of an array of <a class="el" href="channelmap_8h.html#f1cbe2738487c74f99e613779bd34bf2">pa_channel_position</a> values, one for each channel. This array is stored together with a channel count in a <a class="el" href="structpa__channel__map.html" title="A channel map which can be used to attach labels to specific channels of a stream...">pa_channel_map</a> structure.<p> Before filling the structure, the application must initialise it using <a class="el" href="channelmap_8h.html#bf6d26acfe2b0b7147034c19925a714f" title="Initialize the specified channel map and return a pointer to it.">pa_channel_map_init()</a>. There are also a number of convenience functions for standard channel mappings:<p> <ul> <li><a class="el" href="channelmap_8h.html#f32466c8cb879edf9439ec35866760c6" title="Initialize the specified channel map for monoaural audio and return a pointer to...">pa_channel_map_init_mono()</a> - Create a channel map with only mono audio. </li> <li><a class="el" href="channelmap_8h.html#15e329f5ecc28cfb7ea26324a8035d02" title="Initialize the specified channel map for stereophonic audio and return a pointer...">pa_channel_map_init_stereo()</a> - Create a standard stereo mapping. </li> <li><a class="el" href="channelmap_8h.html#b7d13111387d169484853f713b68f9cc" title="Initialize the specified channel map for the specified number of channels using default...">pa_channel_map_init_auto()</a> - Create a standard channel map for up to six channels.</li> </ul> <h2><a class="anchor" name="conv_sec"> Convenience Functions</a></h2> The library contains a number of convenience functions for dealing with channel maps:<p> <ul> <li><a class="el" href="channelmap_8h.html#5d4699c853806a999cbde869dbf7a7ad" title="Return non-zero of the specified channel map is considered valid.">pa_channel_map_valid()</a> - Tests if a channel map is valid. </li> <li><a class="el" href="channelmap_8h.html#851c6c02f0cbfc193d9bacfe42110bd3" title="Compare two channel maps.">pa_channel_map_equal()</a> - Tests if two channel maps are identical. </li> <li><a class="el" href="channelmap_8h.html#5baa37ac22ea08485b12fcce63a98abe" title="Make a humand readable string from the specified channel map.">pa_channel_map_snprint()</a> - Creates a textual description of a channel map. </li> </ul> </div> <hr size="1"><address style="text-align: right;"><small>Generated on Wed Mar 26 12:02:40 2008 for PulseAudio by <a href="http://www.doxygen.org/index.html"> <img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.5.5 </small></address> </body> </html>