1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2<html> 3 4<head> 5<meta http-equiv="Content-Type" content="text/html; charset=windows-1252"> 6<meta name="GENERATOR" content="Microsoft FrontPage 3.0"> 7<meta http-equiv="Content-Style-Type" content="text/css"> 8<link rel="stylesheet" type="text/css" href="../CSS/revolution.css"> 9<title>VISetNextFrameBuffer</title> 10</head> 11 12<body> 13 14<h1 align="left">VISetNextFrameBuffer</h1> 15 16<h2>C Specification</h2> 17 18<dl> 19<dd><pre><code>#include <revolution/vi.h></code></pre> 20 </dd> 21<dd><pre><code>void VISetNextFrameBuffer(void *<em>fb</em>)</code></pre> 22 </dd> 23</dl> 24 25<h2>Arguments</h2> 26 27<table border="1" cellpadding="3" cellspacing="0.1"> 28<TBODY> 29 <tr> 30<td width="120" bgcolor="#ffffe8"><em><strong><code>fb</code></strong></em></td> 31<td width="520">32-byte-aligned pointer to the display frame buffer </td> 32 </tr> 33</TBODY> 34</table> 35 36<h2>Return Values</h2> 37 38<p>None.</p> 39 40<h2>Description</h2> 41 42<p>This function sets a pointer to the display frame buffer in the system DRAM. 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> (for NTSC, EURGB60, or MPAL) or to an initial value of 640 x 574 x <code>VI_DISP_PIX_SZ</code> (for PAL). The pointer, <code>fb</code>, must be 32-byte aligned. </p> 43 44<p>The video controller reads the display frame buffer and outputs pixels to the display with video timing. 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. 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> 45 46<p>The change doesn't take effect until <code><a href="VIFlush.html">VIFlush</a></code> is called. At that point, the contents of the frame buffer will begin being shown from the next vertical retrace after <code><a href="VIFlush.html">VIFlush</a></code> is called. See the <code><a href="VIFlush.html">VIFlush</a></code> function reference for more detail on when the change takes effect.</p> 47 48<h2>See Also</h2> 49 50<p><code><a href="VIWaitForRetrace.html">VIWaitForRetrace</a></code>, <code><a href="VIFlush.html">VIFlush</a></code>, <code><a href="VIGetNextFrameBuffer.html">VIGetNextFrameBuffer</a></code>, <code><a href="VIGetCurrentFrameBuffer.html">VIGetCurrentFrameBuffer</a></code></p> 51 52<h2>Revision History</h2> 53 54<p>2006/03/01 Initial version.</p> 55<hr> 56<P>CONFIDENTIAL</p> 57</BODY> 58</HTML> 59