1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
2<html xml:lang="en-US" lang="en-US" xmlns="http://www.w3.org/1999/xhtml">
3  <head>
4    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
5    <meta http-equiv="Content-Style-Type" content="text/css" />
6    <link rel="stylesheet" href="../../../../css/manpage.css" type="text/css" />
7<title>StartJpegDecoder</title>
8  </head>
9  <body>
10<h1><CODE>nn::jpeg::CTR::JpegMpDecoder::StartJpegDecoder</CODE> Member Function</h1>
11<h2>Syntax</h2>
12    <div class="section">
13      <pre class="definition">#include &lt;nn/jpeg.h&gt;
14
15size_t StartJpegDecoder(
16     void * dst,
17     size_t dstSize,
18     const u8 * src,
19     size_t srcSize,
20     u32 maxWidth,
21     u32 maxHeight,
22     <a href="../../../../nn/jpeg/CTR/PixelFormat.html">PixelFormat</a> dstPixelFormat,
23     bool decodeThumbnail
24);
25</pre>
26    </div>
27<h2>Arguments</h2>
28    <div class="section">
29      <table class="arguments">
30        <thead>
31          <tr>
32            <td width="15" />
33<th>Name</th>
34<td>Description</td>
35          </tr>
36        </thead>
37        <tr>
38<td>out</td>
39<th>dst</th>
40<td>Specifies the buffer that stores the decoded result.<br />Must be 4-byte aligned.<br />Must be 128-byte aligned if you are accessing the output buffer directly as a GPU texture. (No check is made when using this function.)</td>
41        </tr>
42        <tr>
43<td>in</td>
44<th>dstSize</th>
45<td>Specifies the size of <SPAN class="argument">dst</SPAN> in bytes.<br />Specify the return value of <CODE><a href="../../../../nn/jpeg/CTR/JpegMpDecoder/GetDstBufferSize.html">GetDstBufferSize</a></CODE>.</td>
46        </tr>
47        <tr>
48<td>in</td>
49<th>src</th>
50<td>Specifies the JPEG data to decode.</td>
51        </tr>
52        <tr>
53<td>in</td>
54<th>srcSize</th>
55<td>Specifies the size of <SPAN class="argument">src</SPAN> in bytes.</td>
56        </tr>
57        <tr>
58<td>in</td>
59<th>maxWidth</th>
60<td>Specifies the maximum width (in pixels) of an image that can be decoded (equal to or less than 65536). After decoding successfully completes, use the <CODE><a href="../../../../nn/jpeg/CTR/JpegMpDecoder/GetLastWidth.html">GetLastWidth</a></CODE> function to get the actual image width and the <CODE><a href="../../../../nn/jpeg/CTR/JpegMpDecoder/GetLastOutputBufferWidth.html">GetLastOutputBufferWidth</a></CODE> function to get the buffer width.</td>
61        </tr>
62        <tr>
63<td>in</td>
64<th>maxHeight</th>
65<td>Specifies the maximum height (in pixels) of an image that can be decoded (equal to or less than 65536). After decoding successfully completes, use the <CODE><a href="../../../../nn/jpeg/CTR/JpegMpDecoder/GetLastHeight.html">GetLastHeight</a></CODE> function to get the actual image height and the <CODE><a href="../../../../nn/jpeg/CTR/JpegMpDecoder/GetLastOutputBufferHeight.html">GetLastOutputBufferHeight</a></CODE> function to get the buffer height.</td>
66        </tr>
67        <tr>
68<td>in</td>
69<th>dstPixelFormat</th>
70<td>Specifies the output pixel format.</td>
71        </tr>
72        <tr>
73<td>in</td>
74<th>decodeThumbnail</th>
75<td>Specify <CODE>true</CODE> to decode the thumbnail.<br />Specify <CODE>false</CODE> to decode the primary image.</td>
76        </tr> </table>
77    </div>
78<h2>Return Values</h2>
79<div class="section">On success, returns the size (in bytes) of the buffer storing the decoded result.<br />Returns <CODE>0</CODE> on failure.<br />Use the <CODE><a href="../../../../nn/jpeg/CTR/JpegMpEncoder/GetLastError.html">GetLastError</a></CODE> function to get the reason for failure. </div>
80<h2>Description</h2>
81    <div class="section">
82<p>Runs the JPEG decoder.</p><p>Processing takes longer if the image size is not a multiple of 8 or 16 pixels.<br />Depending on the pixel sampling format, images that meet certain conditions can be decoded faster.</p><p><UL> <LI> For <CODE>PIXEL_SAMPLING_YUV444</CODE>, the width and height of the image must both be multiples of 8.<LI> For <CODE>PIXEL_SAMPLING_YUV420</CODE>, the width and height of the image must both be multiples of 16.<LI> For <CODE>PIXEL_SAMPLING_YUV422</CODE>, the height must be a multiple of 8, and the width must be a multiple of 16.</LI></UL></p><p>If JPEG_DECODER_OPTION_MATCH_WIDTH_HEIGHT is specified using <a href="../../../../nn/jpeg/CTR/JpegMpDecoder/SetOption.html">SetOption</a>, the values of arguments maxWidth and maxHeight must match, otherwise decoding will fail.</p><!-- write here --></div>
83<h2>Revision History</h2>
84    <div class="section">
85      <dl class="history">
86        <dt>2010/10/21</dt>
87<dd>Added a description of <CODE>SetOption</CODE>.<br />
88        </dd>
89        <dt>2010/04/14</dt>
90<dd>Initial version.<br />
91        </dd>
92      </dl>
93    </div>
94  <hr><p>CONFIDENTIAL</p></body>
95</html>