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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><!-- /home/edba/dist/qtopia/main-Sunday/qtopia/src/libraries/qtopia/mediarecorderplugininterface.cpp:21 --><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>MediaRecorderEncoder Class</title><style type="text/css"><!--h3.fn,span.fn { margin-left: 1cm; text-indent: -1cm; }a:link { color: #004faf; text-decoration: none }a:visited { color: #672967; text-decoration: none }body { background: #ffffff; color: black; }--></style></head><body><table border="0" cellpadding="0" cellspacing="0" width="100%"><tr><td width="200" align="left" valign="top"><a href="index.html"><img height="27" width="472" src="dochead.png" border="0"></a><br><font face="Arial,Helvetica,Geneva,Swiss,SunSans-Regular" align="center" size=32>Qtopia</font> <a href="index.html">Home</a> - <a href="qtopiaclasses.html">Classes</a> - <a href="qtopiaannotated.html">Annotated</a> - <a href="qtopiafunctions.html">Functions</a> - <a href="qtindex.html">Qt Embedded</a></td><td align="right" valign="top"> <table border="0" cellpadding="0" cellspacing="0" width="137"> <tr> <td><a href="http://www.trolltech.com/company/about/trolls.html"><img height="100" width="100" src="face.png" border="0"></a></td> <td><img height="100" width="100" src="qtlogo.png" align="top" border="0"></td> </tr> </table></td></tr></table><h1 align=center>MediaRecorderEncoder Class Reference</h1><p>The MediaRecorderEncoder class provides an abstract base class forQtopia MediaRecorder encoder plugins.<a href="#details">More...</a><p><tt>#include <<a href="mediarecorderplugininterface-h.html">mediarecorderplugininterface.h</a>></tt><p><a href="mediarecorderencoder-members.html">List of all member functions.</a><h2>Public Members</h2><ul><li><div class=fn>virtual <a href="#~MediaRecorderEncoder"><b>~MediaRecorderEncoder</b></a> ()</div></li><li><div class=fn>virtual int <a href="#pluginNumFormats"><b>pluginNumFormats</b></a> () const = 0</div></li><li><div class=fn>virtual QString <a href="#pluginFormatName"><b>pluginFormatName</b></a> ( int format ) const = 0</div></li><li><div class=fn>virtual QString <a href="#pluginFormatTag"><b>pluginFormatTag</b></a> ( int format ) const = 0</div></li><li><div class=fn>virtual QString <a href="#pluginComment"><b>pluginComment</b></a> () const = 0</div></li><li><div class=fn>virtual double <a href="#pluginVersion"><b>pluginVersion</b></a> () const = 0</div></li><li><div class=fn>virtual QString <a href="#pluginMimeType"><b>pluginMimeType</b></a> () const = 0</div></li><li><div class=fn>virtual bool <a href="#begin"><b>begin</b></a> ( QIODevice * device, const QString & formatTag ) = 0</div></li><li><div class=fn>virtual bool <a href="#end"><b>end</b></a> () = 0</div></li><li><div class=fn>virtual bool <a href="#isActive"><b>isActive</b></a> () const = 0</div></li><li><div class=fn>virtual bool <a href="#setAudioChannels"><b>setAudioChannels</b></a> ( int channels ) = 0</div></li><li><div class=fn>virtual bool <a href="#setAudioFrequency"><b>setAudioFrequency</b></a> ( int frequency ) = 0</div></li><li><div class=fn>virtual bool <a href="#writeAudioSamples"><b>writeAudioSamples</b></a> ( const short * samples, long numSamples ) = 0</div></li><li><div class=fn>virtual bool <a href="#addComment"><b>addComment</b></a> ( const QString & tag, const QString & contents ) = 0</div></li><li><div class=fn>virtual long <a href="#estimateAudioBps"><b>estimateAudioBps</b></a> ( int frequency, int channels, const QString & formatTag ) = 0</div></li><li><div class=fn>virtual bool <a href="#supportsAudio"><b>supportsAudio</b></a> () const = 0</div></li><li><div class=fn>virtual bool <a href="#supportsVideo"><b>supportsVideo</b></a> () const = 0</div></li><li><div class=fn>virtual bool <a href="#supportsComments"><b>supportsComments</b></a> () const = 0</div></li><li><div class=fn>virtual bool <a href="#requiresDirectAccess"><b>requiresDirectAccess</b></a> () const = 0</div></li></ul><hr><a name="details"></a><h2>Detailed Description</h2>The MediaRecorderEncoder class provides an abstract base class forQtopia MediaRecorder encoder plugins.<p> Writing an encoder plugin is achieved by subclassing this base class,reimplementing the pure virtual functions and exporting the class withthe <tt>Q_EXPORT_PLUGIN</tt> macro. See the <a href="pluginintro.html">Plugins documentation</a> for details.<p> The functions in this class are typically used in the following orderwhen recording audio:<p> <pre> <a href="#begin">begin</a>(device, tag); <a href="#addComment">addComment</a>("name", "value"); ... <a href="#addComment">addComment</a>("name", "value"); <a href="#setAudioChannels">setAudioChannels</a>(2); <a href="#setAudioFrequency">setAudioFrequency</a>(44100); <a href="#writeAudioSamples">writeAudioSamples</a>(samples, numSamples); ... <a href="#writeAudioSamples">writeAudioSamples</a>(samples, numSamples); <a href="#end">end</a>(); </pre> <p> <p>See also QIODevice, <a href="mediarecorderplugininterface.html">MediaRecorderPluginInterface</a>, <a href="#begin">begin</a>() and <a href="qtopiaemb.html">Qtopia Classes</a>.<p> <hr><h2>Member Function Documentation</h2><h3 class=fn><a name="~MediaRecorderEncoder"></a>MediaRecorderEncoder::~MediaRecorderEncoder ()<tt> [virtual]</tt></h3><p> Destructs a MediaRecorderEncoder.<h3 class=fn>bool <a name="addComment"></a>MediaRecorderEncoder::addComment ( const QString & tag, const QString & contents )<tt> [pure virtual]</tt></h3><p> Adds a comment string <em>contents</em> tagged as <em>tag</em> to the recorded output. The plugin mayignore tags that it doesn't understand.<p> Returns TRUE if the comment was successfully added (or ignored).Returns FALSE if not recording or the data header has already beenwritten.<p> The data header is considered written upon the first call to<a href="#writeAudioSamples">write audio samples</a>. This is trueeven if plugin's data format places comments at the end of the stream,rather than the front. The plugin should cache the comments untilit is ready to output them.<p> This should only be called if <a href="#supportsComments">comments</a>are supported by the plugin.<p> <p>See also <a href="#begin">begin</a>(), <a href="#writeAudioSamples">writeAudioSamples</a>() and <a href="#supportsComments">supportsComments</a>().<h3 class=fn>bool <a name="begin"></a>MediaRecorderEncoder::begin ( QIODevice * device, const QString & formatTag )<tt> [pure virtual]</tt></h3><p> Begin recording on the specified output <em>device</em>, which must becapable of direct access (seeking) if<a href="#requiresDirectAccess">MediaRecorderEncoder::requiresDirectAccess</a>() returnsTRUE. <em>formatTag</em> selects which format to use.<p> Returns TRUE if recording has begun. Returns FALSE if recordingis already in progress or if <em>device</em> is not capable of seeking.<p> This call will typically be followed by calls to set the<a href="#setAudioChannels">channels</a>,<a href="#setAudioFrequency">frequency</a>,and <a href="#addComment">file comments</a>.<p> <p>See also <a href="#setAudioChannels">setAudioChannels</a>(), <a href="#setAudioFrequency">setAudioFrequency</a>(), <a href="#addComment">addComment</a>(), <a href="#writeAudioSamples">writeAudioSamples</a>() and <a href="#requiresDirectAccess">requiresDirectAccess</a>().<h3 class=fn>bool <a name="end"></a>MediaRecorderEncoder::end ()<tt> [pure virtual]</tt></h3><p> End recording on the current output device. This function mayback-patch earlier bytes in the output. Once it has finishedoutputting the data, it will leave the device positioned afterall bytes that were written.<p> Returns TRUE if recording was successfully terminated.Returns FALSE if not currently recording, or there was anerror writing to the device.<h3 class=fn>long <a name="estimateAudioBps"></a>MediaRecorderEncoder::estimateAudioBps ( int frequency, int channels, const QString & formatTag )<tt> [pure virtual]</tt></h3><p> Estimate the number of bytes per second that are needed to recordaudio in the <em>formatTag</em> format at a given <em>frequency</em> with thespecified number of <em>channels</em>.<h3 class=fn>bool <a name="isActive"></a>MediaRecorderEncoder::isActive () const<tt> [pure virtual]</tt></h3><p> Returns TRUE if the recorder is currently active; FALSE otherwise.<h3 class=fn>QString <a name="pluginComment"></a>MediaRecorderEncoder::pluginComment () const<tt> [pure virtual]</tt></h3><p> Returns a comment that describes the purpose of the plugin.<h3 class=fn>QString <a name="pluginFormatName"></a>MediaRecorderEncoder::pluginFormatName ( int format ) const<tt> [pure virtual]</tt></h3><p> Returns the name of one of a plugin's data format, e.g. "Wav Format".The data format is selected using <em>format</em> as an index. The name may be displayed to the user in a list of supported recording formats.<h3 class=fn>QString <a name="pluginFormatTag"></a>MediaRecorderEncoder::pluginFormatTag ( int format ) const<tt> [pure virtual]</tt></h3><p> Returns the tag name of a plugin's data format. For example, "pcm".The data format is selected using <em>format</em> as an index. This value is used with MediaRecorderEncoder::begin .<h3 class=fn>QString <a name="pluginMimeType"></a>MediaRecorderEncoder::pluginMimeType () const<tt> [pure virtual]</tt></h3><p> Returns the MIME type for the plugin's recommended file extension, e.g.<tt>audio/x-wav</tt><h3 class=fn>int <a name="pluginNumFormats"></a>MediaRecorderEncoder::pluginNumFormats () const<tt> [pure virtual]</tt></h3><p> Returns the number of formats that are supported by this plugin.<h3 class=fn>double <a name="pluginVersion"></a>MediaRecorderEncoder::pluginVersion () const<tt> [pure virtual]</tt></h3><p> Returns the version of the plugin. Normally 1.0.<h3 class=fn>bool <a name="requiresDirectAccess"></a>MediaRecorderEncoder::requiresDirectAccess () const<tt> [pure virtual]</tt></h3><p> Returns TRUE if this plugin must be supplied a direct access (seekable)output device.<p> <p>See also <a href="#begin">begin</a>().<h3 class=fn>bool <a name="setAudioChannels"></a>MediaRecorderEncoder::setAudioChannels ( int channels )<tt> [pure virtual]</tt></h3><p> Sets the number of audio channels in the recorded data to either 1 or 2.<p> Returns TRUE if the channel count was set successfully. Returns FALSEif not recording, the data header has already been written, or if<em>channels</em> is neither 1 nor 2.<p> The data header is considered written upon the first call to<a href="#writeAudioSamples">write audio samples</a>.<p> <p>See also <a href="#begin">begin</a>(), <a href="#setAudioFrequency">setAudioFrequency</a>() and <a href="#writeAudioSamples">writeAudioSamples</a>().<h3 class=fn>bool <a name="setAudioFrequency"></a>MediaRecorderEncoder::setAudioFrequency ( int frequency )<tt> [pure virtual]</tt></h3><p> Sets the audio sample frequency in the recorded data.<p> Returns TRUE if the frequency was set successfuly. Returns FALSEif not recording, the data header has already been written, or if<em>frequency</em> is less than or equal to zero.<p> The data header is considered written upon the first call to<a href="#writeAudioSamples">write audio samples</a>.<p> <p>See also <a href="#begin">begin</a>(), <a href="#setAudioChannels">setAudioChannels</a>() and <a href="#writeAudioSamples">writeAudioSamples</a>().<h3 class=fn>bool <a name="supportsAudio"></a>MediaRecorderEncoder::supportsAudio () const<tt> [pure virtual]</tt></h3><p> Returns TRUE if this plugin supports audio; FALSE otherwise.<h3 class=fn>bool <a name="supportsComments"></a>MediaRecorderEncoder::supportsComments () const<tt> [pure virtual]</tt></h3><p> Returns TRUE if this plugin supports comments; FALSE otherwise.<p> <p>See also <a href="#addComment">addComment</a>().<h3 class=fn>bool <a name="supportsVideo"></a>MediaRecorderEncoder::supportsVideo () const<tt> [pure virtual]</tt></h3><p> Returns TRUE if this plugin supports video; FALSE otherwise.<h3 class=fn>bool <a name="writeAudioSamples"></a>MediaRecorderEncoder::writeAudioSamples ( const short * samples, long numSamples )<tt> [pure virtual]</tt></h3><p> Writes a buffer of audio samples to the recorded output.<p> Samples are assumed to always be 16-bit and in host byte order.It is the responsibility of the caller to rescale other sample sizes.<p> The <em>numSamples</em> value is the number of 16-bit quantities in the<em>samples</em> buffer. This will be a multiple of two for stereo data,with alternating channel samples.<p> Returns TRUE if the samples were successfully written. Returns FALSEif not recording or there was an error writing to the output device.<p> <p>See also <a href="#begin">begin</a>(), <a href="#setAudioChannels">setAudioChannels</a>() and <a href="#setAudioFrequency">setAudioFrequency</a>().<!-- eof --><hr><p>This file is part of the <a href="../index.html">Qtopia</a> platform,copyright © 1995-2004<a href="http://www.trolltech.com/">Trolltech</a>, all rights reserved.<p><address><hr><div align="center"><table width="100%" cellspacing="0" border="0"><tr><td>Copyright © 2001-2004 Trolltech<td><a href="http://www.trolltech.com/trademarks.html">Trademarks</a><td align="right"><div align="right">Qtopia version 2.0.0</div></table></div></address></body></html>⌨️ 快捷键说明
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