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<li class="level1"><a href="#public-types">Public Types</a></li>
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<h1 class="title">QAbstractVideoBuffer Class Reference</h1>
<!-- $$$QAbstractVideoBuffer-brief -->
<p>The QAbstractVideoBuffer class is an abstraction for video data. <a href="#details">More...</a></p>
<!-- @@@QAbstractVideoBuffer -->
<pre class="cpp"> <span class="preprocessor">#include <QAbstractVideoBuffer></span></pre><p>This class was introduced in Qt 4.6.</p>
<ul>
<li><a href="qabstractvideobuffer-members.html">List of all members, including inherited members</a></li>
</ul>
<a name="public-types"></a>
<h2>Public Types</h2>
<table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> enum </td><td class="memItemRight bottomAlign"><b><a href="qabstractvideobuffer.html#HandleType-enum">HandleType</a></b> { NoHandle, GLTextureHandle, XvShmImageHandle, CoreImageHandle, QPixmapHandle, UserHandle }</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> enum </td><td class="memItemRight bottomAlign"><b><a href="qabstractvideobuffer.html#MapMode-enum">MapMode</a></b> { NotMapped, ReadOnly, WriteOnly, ReadWrite }</td></tr>
</table>
<a name="public-functions"></a>
<h2>Public Functions</h2>
<table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qabstractvideobuffer.html#QAbstractVideoBuffer">QAbstractVideoBuffer</a></b> ( HandleType <i>type</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual </td><td class="memItemRight bottomAlign"><b><a href="qabstractvideobuffer.html#dtor.QAbstractVideoBuffer">~QAbstractVideoBuffer</a></b> ()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual QVariant </td><td class="memItemRight bottomAlign"><b><a href="qabstractvideobuffer.html#handle">handle</a></b> () const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> HandleType </td><td class="memItemRight bottomAlign"><b><a href="qabstractvideobuffer.html#handleType">handleType</a></b> () const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual uchar * </td><td class="memItemRight bottomAlign"><b><a href="qabstractvideobuffer.html#map">map</a></b> ( MapMode <i>mode</i>, int * <i>numBytes</i>, int * <i>bytesPerLine</i> ) = 0</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual MapMode </td><td class="memItemRight bottomAlign"><b><a href="qabstractvideobuffer.html#mapMode">mapMode</a></b> () const = 0</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractvideobuffer.html#unmap">unmap</a></b> () = 0</td></tr>
</table>
<a name="details"></a>
<!-- $$$QAbstractVideoBuffer-description -->
<div class="descr">
<h2>Detailed Description</h2>
<p>The QAbstractVideoBuffer class is an abstraction for video data.</p>
<p>The <a href="qvideoframe.html">QVideoFrame</a> class makes use of a QAbstractVideoBuffer internally to reference a buffer of video data. Creating a subclass of QAbstractVideoBuffer will allow you to construct video frames from preallocated or static buffers.</p>
<p>The contents of a buffer can be accessed by mapping the buffer to memory using the <a href="qabstractvideobuffer.html#map">map</a>() function which returns a pointer to memory containing the contents of the the video buffer. The memory returned by <a href="qabstractvideobuffer.html#map">map</a>() is released by calling the <a href="qabstractvideobuffer.html#unmap">unmap</a>() function.</p>
<p>The <a href="qabstractvideobuffer.html#handle">handle</a>() of a buffer may also be used to manipulate it's contents using type specific APIs. The type of a buffer's handle is given by the <a href="qabstractvideobuffer.html#handleType">handleType</a>() function.</p>
</div>
<p><b>See also </b><a href="qvideoframe.html">QVideoFrame</a>.</p>
<!-- @@@QAbstractVideoBuffer -->
<div class="types">
<h2>Member Type Documentation</h2>
<!-- $$$HandleType$$$NoHandle$$$GLTextureHandle$$$XvShmImageHandle$$$CoreImageHandle$$$QPixmapHandle$$$UserHandle -->
<h3 class="fn"><a name="HandleType-enum"></a>enum QAbstractVideoBuffer::<span class="name">HandleType</span></h3>
<p>Identifies the type of a video buffers handle.</p>
<table class="valuelist"><tr valign="top" class="odd"><th class="tblConst">Constant</th><th class="tblval">Value</th><th class="tbldscr">Description</th></tr>
<tr><td class="topAlign"><tt>QAbstractVideoBuffer::NoHandle</tt></td><td class="topAlign"><tt>0</tt></td><td class="topAlign">The buffer has no handle, its data can only be accessed by mapping the buffer.</td></tr>
<tr><td class="topAlign"><tt>QAbstractVideoBuffer::GLTextureHandle</tt></td><td class="topAlign"><tt>1</tt></td><td class="topAlign">The handle of the buffer is an OpenGL texture ID.</td></tr>
<tr><td class="topAlign"><tt>QAbstractVideoBuffer::XvShmImageHandle</tt></td><td class="topAlign"><tt>2</tt></td><td class="topAlign">The handle contains pointer to shared memory XVideo image.</td></tr>
<tr><td class="topAlign"><tt>QAbstractVideoBuffer::CoreImageHandle</tt></td><td class="topAlign"><tt>3</tt></td><td class="topAlign">The handle contains pointer to Mac OS X CIImage.</td></tr>
<tr><td class="topAlign"><tt>QAbstractVideoBuffer::QPixmapHandle</tt></td><td class="topAlign"><tt>4</tt></td><td class="topAlign">The handle of the buffer is a <a href="qpixmap.html">QPixmap</a>.</td></tr>
<tr><td class="topAlign"><tt>QAbstractVideoBuffer::UserHandle</tt></td><td class="topAlign"><tt>1000</tt></td><td class="topAlign">Start value for user defined handle types.</td></tr>
</table>
<p><b>See also </b><a href="qabstractvideobuffer.html#handleType">handleType</a>().</p>
<!-- @@@HandleType -->
<!-- $$$MapMode$$$NotMapped$$$ReadOnly$$$WriteOnly$$$ReadWrite -->
<h3 class="fn"><a name="MapMode-enum"></a>enum QAbstractVideoBuffer::<span class="name">MapMode</span></h3>
<p>Enumerates how a video buffer's data is mapped to memory.</p>
<table class="valuelist"><tr valign="top" class="odd"><th class="tblConst">Constant</th><th class="tblval">Value</th><th class="tbldscr">Description</th></tr>
<tr><td class="topAlign"><tt>QAbstractVideoBuffer::NotMapped</tt></td><td class="topAlign"><tt>0x00</tt></td><td class="topAlign">The video buffer has is not mapped to memory.</td></tr>
<tr><td class="topAlign"><tt>QAbstractVideoBuffer::ReadOnly</tt></td><td class="topAlign"><tt>0x01</tt></td><td class="topAlign">The mapped memory is populated with data from the video buffer when mapped, but the content of the mapped memory may be discarded when unmapped.</td></tr>
<tr><td class="topAlign"><tt>QAbstractVideoBuffer::WriteOnly</tt></td><td class="topAlign"><tt>0x02</tt></td><td class="topAlign">The mapped memory is uninitialized when mapped, and the content will be used to populate the video buffer when unmapped.</td></tr>
<tr><td class="topAlign"><tt>QAbstractVideoBuffer::ReadWrite</tt></td><td class="topAlign"><tt>ReadOnly | WriteOnly</tt></td><td class="topAlign">The mapped memory is populated with data from the video buffer, and the video buffer is repopulated with the content of the mapped memory.</td></tr>
</table>
<p><b>See also </b><a href="qabstractvideobuffer.html#mapMode">mapMode</a>() and <a href="qabstractvideobuffer.html#map">map</a>().</p>
<!-- @@@MapMode -->
</div>
<div class="func">
<h2>Member Function Documentation</h2>
<!-- $$$QAbstractVideoBuffer[overload1]$$$QAbstractVideoBufferHandleType -->
<h3 class="fn"><a name="QAbstractVideoBuffer"></a>QAbstractVideoBuffer::<span class="name">QAbstractVideoBuffer</span> ( <span class="type"><a href="qabstractvideobuffer.html#HandleType-enum">HandleType</a></span> <i>type</i> )</h3>
<p>Constructs an abstract video buffer of the given <i>type</i>.</p>
<!-- @@@QAbstractVideoBuffer -->
<!-- $$$~QAbstractVideoBuffer[overload1]$$$~QAbstractVideoBuffer -->
<h3 class="fn"><a name="dtor.QAbstractVideoBuffer"></a>QAbstractVideoBuffer::<span class="name">~QAbstractVideoBuffer</span> ()<tt> [virtual]</tt></h3>
<p>Destroys an abstract video buffer.</p>
<!-- @@@~QAbstractVideoBuffer -->
<!-- $$$handle[overload1]$$$handle -->
<h3 class="fn"><a name="handle"></a><span class="type"><a href="qvariant.html">QVariant</a></span> QAbstractVideoBuffer::<span class="name">handle</span> () const<tt> [virtual]</tt></h3>
<p>Returns a type specific handle to the data buffer.</p>
<p>The type of the handle is given by <a href="qabstractvideobuffer.html#handleType">handleType</a>() function.</p>
<p><b>See also </b><a href="qabstractvideobuffer.html#handleType">handleType</a>().</p>
<!-- @@@handle -->
<!-- $$$handleType[overload1]$$$handleType -->
<h3 class="fn"><a name="handleType"></a><span class="type"><a href="qabstractvideobuffer.html#HandleType-enum">HandleType</a></span> QAbstractVideoBuffer::<span class="name">handleType</span> () const</h3>
<p>Returns the type of a video buffer's handle.</p>
<p><b>See also </b><a href="qabstractvideobuffer.html#handle">handle</a>().</p>
<!-- @@@handleType -->
<!-- $$$map[overload1]$$$mapMapModeint*int* -->
<h3 class="fn"><a name="map"></a><span class="type"><a href="qtglobal.html#uchar-typedef">uchar</a></span> * QAbstractVideoBuffer::<span class="name">map</span> ( <span class="type"><a href="qabstractvideobuffer.html#MapMode-enum">MapMode</a></span> <i>mode</i>, <span class="type">int</span> * <i>numBytes</i>, <span class="type">int</span> * <i>bytesPerLine</i> )<tt> [pure virtual]</tt></h3>
<p>Maps the contents of a video buffer to memory.</p>
<p>The map <i>mode</i> indicates whether the contents of the mapped memory should be read from and/or written to the buffer. If the map mode includes the <a href="qabstractvideobuffer.html#MapMode-enum">QAbstractVideoBuffer::ReadOnly</a> flag the mapped memory will be populated with the content of the video buffer when mapped. If the map mode includes the <a href="qabstractvideobuffer.html#MapMode-enum">QAbstractVideoBuffer::WriteOnly</a> flag the content of the mapped memory will be persisted in the buffer when unmapped.</p>
<p>When access to the data is no longer needed be sure to call the <a href="qabstractvideobuffer.html#unmap">unmap</a>() function to release the mapped memory.</p>
<p>Returns a pointer to the mapped memory region, or a null pointer if the mapping failed. The size in bytes of the mapped memory region is returned in <i>numBytes</i>, and the line stride in <i>bytesPerLine</i>.</p>
<p>When access to the data is no longer needed be sure to <a href="qabstractvideobuffer.html#unmap">unmap</a>() the buffer.</p>
<p><b>Note:</b> Writing to memory that is mapped as read-only is undefined, and may result in changes to shared data.</p>
<p><b>See also </b><a href="qabstractvideobuffer.html#unmap">unmap</a>() and <a href="qabstractvideobuffer.html#mapMode">mapMode</a>().</p>
<!-- @@@map -->
<!-- $$$mapMode[overload1]$$$mapMode -->
<h3 class="fn"><a name="mapMode"></a><span class="type"><a href="qabstractvideobuffer.html#MapMode-enum">MapMode</a></span> QAbstractVideoBuffer::<span class="name">mapMode</span> () const<tt> [pure virtual]</tt></h3>
<p>Returns the mode a video buffer is mapped in.</p>
<p><b>See also </b><a href="qabstractvideobuffer.html#map">map</a>().</p>
<!-- @@@mapMode -->
<!-- $$$unmap[overload1]$$$unmap -->
<h3 class="fn"><a name="unmap"></a><span class="type">void</span> QAbstractVideoBuffer::<span class="name">unmap</span> ()<tt> [pure virtual]</tt></h3>
<p>Releases the memory mapped by the <a href="qabstractvideobuffer.html#map">map</a>() function</p>
<p>If the <a href="qabstractvideobuffer.html#MapMode-enum">MapMode</a> included the <a href="qabstractvideobuffer.html#MapMode-enum">QAbstractVideoBuffer::WriteOnly</a> flag this will persist the current content of the mapped memory to the video frame.</p>
<p><b>See also </b><a href="qabstractvideobuffer.html#map">map</a>().</p>
<!-- @@@unmap -->
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