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13
14<h1 align="left">VISetNextFrameBuffer</h1>
15
16<h2>Syntax</h2>
17<dl><dd><pre class="construction">#include &lt;revolution/vi.h&gt;
18
19void VISetNextFrameBuffer(void *fb);
20</pre></dd></dl>
21
22<h2>Arguments</h2>
23<TABLE class="arguments" border="1" >
24<TBODY>
25  <tr>
26<th>fb</th>
27<td>32-byte-aligned pointer to the display frame buffer.</td>
28  </tr>
29</TBODY>
30</table>
31
32<h2>Return Values</h2>
33<p>None.</p>
34
35<h2>Description</h2>
36<p>This function sets a pointer to the display frame buffer in the system DRAM.&nbsp;The frame buffer size is set by the <code>VIInit</code> function to an initial value of 640 x 480 x <CODE>VI_DISP_PIX_SZ</CODE> (NTSC or EURGB60) or 640 x 574 x <code>VI_DISP_PIX_SZ</code> (PAL). The pointer, <SPAN class="argument">fb</SPAN>, must be 32-byte aligned.</p>
37
38<p>The video controller reads the display frame buffer and outputs pixels to the display with video timing.&nbsp;The embedded frame buffer will be copied to the display frame buffer during the vertical retrace interval. This allows single buffering of the display buffer in system DRAM.&nbsp;The display buffer is converted from 24-bit RGB to 4:2:2 YUV (2 bytes/pixel) during the copy. This reduces by a third the amount of system DRAM needed for the display frame buffer, without reducing image quality for NTSC and PAL displays.</p>
39
40<p>The change does not take effect until <a href="VIFlush.html"><code>VIFlush</code></a> is called. At that point, the contents of the frame buffer will begin being shown from the next vertical retrace after <a href="VIFlush.html"><code>VIFlush</code></a> is called. See the <a href="VIFlush.html"><code>VIFlush</code></a> function reference for more details about when the change takes effect.</p>
41
42<h2>See Also</h2>
43<P class="reference">
44<a href="VIWaitForRetrace.html">VIWaitForRetrace</a>,
45<a href="VIFlush.html">VIFlush</a>,
46<a href="VIGetNextFrameBuffer.html">VIGetNextFrameBuffer</a>,
47<a href="VIGetCurrentFrameBuffer.html">VIGetCurrentFrameBuffer</a>
48</p>
49
50<h2>Revision History</h2>
51<p>
522007/12/04 Deleted the MPAL description.</br>2006/03/01 Initial version.<br>
53</p>
54
55<hr><p>CONFIDENTIAL</p></body>
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