versions/master/how_to/recordio.html - mxnet-test - Git at Google

 <!DOCTYPE html>

 <html lang="en">
 <head>
 <meta charset="utf-8"/>
 <meta content="IE=edge" http-equiv="X-UA-Compatible"/>
 <meta content="width=device-width, initial-scale=1" name="viewport"/>
 <title>Create a Dataset Using RecordIO — mxnet  documentation</title>
 <link crossorigin="anonymous" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" rel="stylesheet"/>
 <link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css" rel="stylesheet"/>
 <link href="../_static/basic.css" rel="stylesheet" type="text/css">
 <link href="../_static/pygments.css" rel="stylesheet" type="text/css">
 <link href="../_static/mxnet.css" rel="stylesheet" type="text/css"/>
 <script type="text/javascript">
       var DOCUMENTATION_OPTIONS = {
         URL_ROOT:    '../',
         VERSION:     '',
         COLLAPSE_INDEX: false,
         FILE_SUFFIX: '.html',
         HAS_SOURCE:  true,
         SOURCELINK_SUFFIX: ''
       };
     </script>
 <script src="../_static/jquery-1.11.1.js" type="text/javascript"></script>
 <script src="../_static/underscore.js" type="text/javascript"></script>
 <script src="../_static/searchtools_custom.js" type="text/javascript"></script>
 <script src="../_static/doctools.js" type="text/javascript"></script>
 <script src="../_static/selectlang.js" type="text/javascript"></script>
 <script src="https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript"></script>
 <script type="text/javascript"> jQuery(function() { Search.loadIndex("/searchindex.js"); Search.init();}); </script>
 <script>
       (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
       (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new
       Date();a=s.createElement(o),
       m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
       })(window,document,'script','https://www.google-analytics.com/analytics.js','ga');

       ga('create', 'UA-96378503-1', 'auto');
       ga('send', 'pageview');

     </script>
 <!-- -->
 <!-- <script type="text/javascript" src="../_static/jquery.js"></script> -->
 <!-- -->
 <!-- <script type="text/javascript" src="../_static/underscore.js"></script> -->
 <!-- -->
 <!-- <script type="text/javascript" src="../_static/doctools.js"></script> -->
 <!-- -->
 <!-- <script type="text/javascript" src="https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script> -->
 <!-- -->
 <link href="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/mxnet-icon.png" rel="icon" type="image/png"/>
 </link></link></head>
 <body role="document"><!-- Previous Navbar Layout
 <div class="navbar navbar-default navbar-fixed-top">
   <div class="container">
     <div class="navbar-header">
       <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
         <span class="sr-only">Toggle navigation</span>
         <span class="icon-bar"></span>
         <span class="icon-bar"></span>
         <span class="icon-bar"></span>
       </button>
       <a href="../" class="navbar-brand">
         <img src="http://data.mxnet.io/theme/mxnet.png">
       </a>
     </div>
     <div id="navbar" class="navbar-collapse collapse">
       <ul id="navbar" class="navbar navbar-left">

         <li> <a href="../get_started/index.html">Get Started</a> </li>

         <li> <a href="../tutorials/index.html">Tutorials</a> </li>

         <li> <a href="../how_to/index.html">How To</a> </li>


         <li class="dropdown">
           <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="true">Packages <span class="caret"></span></a>
           <ul class="dropdown-menu">

             <li><a href="../packages/python/index.html">
                 Python
             </a></li>

             <li><a href="../packages/r/index.html">
                 R
             </a></li>

             <li><a href="../packages/julia/index.html">
                 Julia
             </a></li>

             <li><a href="../packages/c++/index.html">
                 C++
             </a></li>

             <li><a href="../packages/scala/index.html">
                 Scala
             </a></li>

             <li><a href="../packages/perl/index.html">
                 Perl
             </a></li>

           </ul>
         </li>

         <li> <a href="../system/index.html">System</a> </li>
         <li>
 <form class="" role="search" action="../search.html" method="get" autocomplete="off">
   <div class="form-group inner-addon left-addon">
     <i class="glyphicon glyphicon-search"></i>
     <input type="text" name="q" class="form-control" placeholder="Search">
   </div>
   <input type="hidden" name="check_keywords" value="yes" />
   <input type="hidden" name="area" value="default" />

 </form> </li>
       </ul>
       <ul id="navbar" class="navbar navbar-right">
         <li> <a href="../index.html"><span class="flag-icon flag-icon-us"></span></a> </li>
         <li> <a href="..//zh/index.html"><span class="flag-icon flag-icon-cn"></span></a> </li>
       </ul>
     </div>
   </div>
 </div>
 Previous Navbar Layout End -->
 <div class="navbar navbar-fixed-top">
 <div class="container" id="navContainer">
 <div class="innder" id="header-inner">
 <h1 id="logo-wrap">
 <a href="../" id="logo"><img src="http://data.mxnet.io/theme/mxnet.png"/></a>
 </h1>
 <nav class="nav-bar" id="main-nav">
 <a class="main-nav-link" href="../get_started/install.html">Install</a>
 <a class="main-nav-link" href="../tutorials/index.html">Tutorials</a>
 <a class="main-nav-link" href="../how_to/index.html">How To</a>
 <span id="dropdown-menu-position-anchor">
 <a aria-expanded="true" aria-haspopup="true" class="main-nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button">API <span class="caret"></span></a>
 <ul class="dropdown-menu" id="package-dropdown-menu">
 <li><a class="main-nav-link" href="../api/python/index.html">Python</a></li>
 <li><a class="main-nav-link" href="../api/scala/index.html">Scala</a></li>
 <li><a class="main-nav-link" href="../api/r/index.html">R</a></li>
 <li><a class="main-nav-link" href="../api/julia/index.html">Julia</a></li>
 <li><a class="main-nav-link" href="../api/c++/index.html">C++</a></li>
 <li><a class="main-nav-link" href="../api/perl/index.html">Perl</a></li>
 </ul>
 </span>
 <a class="main-nav-link" href="../architecture/index.html">Architecture</a>
 <!-- <a class="main-nav-link" href="../community/index.html">Community</a> -->
 <a class="main-nav-link" href="https://github.com/dmlc/mxnet">Github</a>
 <span id="dropdown-menu-position-anchor-version" style="position: relative"><a href="#" class="main-nav-link dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="true">Versions(master)<span class="caret"></span></a><ul id="package-dropdown-menu" class="dropdown-menu"><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/test/>v0.10.14</a></li><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/test/versions/0.10/index.html>0.10</a></li><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/test/versions/master/index.html>master</a></li></ul></span></nav>
 <script> function getRootPath(){ return "../" } </script>
 <div class="burgerIcon dropdown">
 <a class="dropdown-toggle" data-toggle="dropdown" href="#" role="button">☰</a>
 <ul class="dropdown-menu dropdown-menu-right" id="burgerMenu">
 <li><a href="../get_started/install.html">Install</a></li>
 <li><a href="../tutorials/index.html">Tutorials</a></li>
 <li><a href="../how_to/index.html">How To</a></li>
 <li class="dropdown-submenu">
 <a href="#" tabindex="-1">API</a>
 <ul class="dropdown-menu">
 <li><a href="../api/python/index.html" tabindex="-1">Python</a>
 </li>
 <li><a href="../api/scala/index.html" tabindex="-1">Scala</a>
 </li>
 <li><a href="../api/r/index.html" tabindex="-1">R</a>
 </li>
 <li><a href="../api/julia/index.html" tabindex="-1">Julia</a>
 </li>
 <li><a href="../api/c++/index.html" tabindex="-1">C++</a>
 </li>
 <li><a href="../api/perl/index.html" tabindex="-1">Perl</a>
 </li>
 </ul>
 </li>
 <li><a href="../architecture/index.html">Architecture</a></li>
 <li><a class="main-nav-link" href="https://github.com/dmlc/mxnet">Github</a></li>
 <li id="dropdown-menu-position-anchor-version-mobile" class="dropdown-submenu" style="position: relative"><a href="#" tabindex="-1">Versions(master)</a><ul class="dropdown-menu"><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/test/>v0.10.14</a></li><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/test/versions/0.10/index.html>0.10</a></li><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/test/versions/master/index.html>master</a></li></ul></li></ul>
 </div>
 <div class="plusIcon dropdown">
 <a class="dropdown-toggle" data-toggle="dropdown" href="#" role="button"><span aria-hidden="true" class="glyphicon glyphicon-plus"></span></a>
 <ul class="dropdown-menu dropdown-menu-right" id="plusMenu"></ul>
 </div>
 <div id="search-input-wrap">
 <form action="../search.html" autocomplete="off" class="" method="get" role="search">
 <div class="form-group inner-addon left-addon">
 <i class="glyphicon glyphicon-search"></i>
 <input class="form-control" name="q" placeholder="Search" type="text"/>
 </div>
 <input name="check_keywords" type="hidden" value="yes">
 <input name="area" type="hidden" value="default"/>
 </input></form>
 <div id="search-preview"></div>
 </div>
 <div id="searchIcon">
 <span aria-hidden="true" class="glyphicon glyphicon-search"></span>
 </div>
 <!-- <div id="lang-select-wrap"> -->
 <!--   <label id="lang-select-label"> -->
 <!--     <\!-- <i class="fa fa-globe"></i> -\-> -->
 <!--     <span></span> -->
 <!--   </label> -->
 <!--   <select id="lang-select"> -->
 <!--     <option value="en">Eng</option> -->
 <!--     <option value="zh">中文</option> -->
 <!--   </select> -->
 <!-- </div> -->
 <!--     <a id="mobile-nav-toggle">
         <span class="mobile-nav-toggle-bar"></span>
         <span class="mobile-nav-toggle-bar"></span>
         <span class="mobile-nav-toggle-bar"></span>
       </a> -->
 </div>
 </div>
 </div>
 <div class="container">
 <div class="row">
 <div aria-label="main navigation" class="sphinxsidebar leftsidebar" role="navigation">
 <div class="sphinxsidebarwrapper">
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../api/python/index.html">Python Documents</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../api/r/index.html">R Documents</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../api/julia/index.html">Julia Documents</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../api/c++/index.html">C++ Documents</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../api/scala/index.html">Scala Documents</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../api/perl/index.html">Perl Documents</a></li>
 <li class="toctree-l1"><a class="reference internal" href="index.html">HowTo Documents</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../architecture/index.html">System Documents</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../tutorials/index.html">Tutorials</a></li>
 </ul>
 </div>
 </div>
 <div class="content">
 <div class="section" id="create-a-dataset-using-recordio">
 <span id="create-a-dataset-using-recordio"></span><h1>Create a Dataset Using RecordIO<a class="headerlink" href="#create-a-dataset-using-recordio" title="Permalink to this headline">¶</a></h1>
 <p>RecordIO implements a file format for a sequence of records. We recommend storing images as records and packing them together. The benefits include:</p>
 <ul class="simple">
 <li>Storing images in a compact format–e.g., JPEG, for records–greatly reduces the size of the dataset on the disk.</li>
 <li>Packing data together allows continuous reading on the disk.</li>
 <li>RecordIO has a simple way to partition, simplifying distributed setting. We provide an example later.</li>
 </ul>
 <p>We provide the <a class="reference external" href="https://github.com/dmlc/mxnet/blob/master/tools/im2rec.cc">im2rec tool</a> so you can create an Image RecordIO dataset by yourself. The following walkthrough shows you how.</p>
 <div class="section" id="prerequisites">
 <span id="prerequisites"></span><h2>Prerequisites<a class="headerlink" href="#prerequisites" title="Permalink to this headline">¶</a></h2>
 <p>Download the data. You don’t need to resize the images manually. You can use <code class="docutils literal"><span class="pre">im2rec</span></code> to resize them automatically. For details, see the “Extension: Using Multiple Labels for a Single Image,” later in this topic.</p>
 </div>
 <div class="section" id="step-1-make-an-image-list-file">
 <span id="step-1-make-an-image-list-file"></span><h2>Step 1. Make an Image List File<a class="headerlink" href="#step-1-make-an-image-list-file" title="Permalink to this headline">¶</a></h2>
 <p>After you download the data, you need to make an image list file.  The format is:</p>
 <div class="highlight-python"><div class="highlight"><pre><span></span>integer_image_index \t label_index \t path_to_image
 </pre></div>
 </div>
 <p>Typically, the program takes the list of names of all of the images, shuffles them, then separates them into two lists: a training filename list and a testing filename list. Write the list in the right format.</p>
 <p>This is an example file:</p>
 <div class="highlight-bash"><div class="highlight"><pre><span></span><span class="m">95099</span>  <span class="m">464</span>     n04467665_17283.JPEG
 <span class="m">10025081</span>        <span class="m">412</span>     ILSVRC2010_val_00025082.JPEG
 <span class="m">74181</span>   <span class="m">789</span>     n01915811_2739.JPEG
 <span class="m">10035553</span>        <span class="m">859</span>     ILSVRC2010_val_00035554.JPEG
 <span class="m">10048727</span>        <span class="m">929</span>     ILSVRC2010_val_00048728.JPEG
 <span class="m">94028</span>   <span class="m">924</span>     n01980166_4956.JPEG
 <span class="m">1080682</span> <span class="m">650</span>     n11807979_571.JPEG
 <span class="m">972457</span>  <span class="m">633</span>     n07723039_1627.JPEG
 <span class="m">7534</span>    <span class="m">11</span>      n01630670_4486.JPEG
 <span class="m">1191261</span> <span class="m">249</span>     n12407079_5106.JPEG
 </pre></div>
 </div>
 </div>
 <div class="section" id="step-2-create-the-binary-file">
 <span id="step-2-create-the-binary-file"></span><h2>Step 2. Create the Binary File<a class="headerlink" href="#step-2-create-the-binary-file" title="Permalink to this headline">¶</a></h2>
 <p>To generate a binary image, use <code class="docutils literal"><span class="pre">im2rec</span></code> in the tool folder. <code class="docutils literal"><span class="pre">im2rec</span></code> takes the path of the <code class="docutils literal"><span class="pre">_image</span> <span class="pre">list</span> <span class="pre">file_</span></code> you generated, the <code class="docutils literal"><span class="pre">_root</span> <span class="pre">path_</span></code> of the images, and the <code class="docutils literal"><span class="pre">_output</span> <span class="pre">file</span> <span class="pre">path_</span></code> as input. This process usually takes several hours, so be patient.</p>
 <p>Sample command:</p>
 <div class="highlight-bash"><div class="highlight"><pre><span></span>./bin/im2rec image.lst image_root_dir output.bin <span class="nv">resize</span><span class="o">=</span><span class="m">256</span>
 </pre></div>
 </div>
 <p>For more details, run <code class="docutils literal"><span class="pre">./bin/im2rec</span></code>.</p>
 </div>
 <div class="section" id="extension-multiple-labels-for-a-single-image">
 <span id="extension-multiple-labels-for-a-single-image"></span><h2>Extension: Multiple Labels for a Single Image<a class="headerlink" href="#extension-multiple-labels-for-a-single-image" title="Permalink to this headline">¶</a></h2>
 <p>The <code class="docutils literal"><span class="pre">im2rec</span></code> tool and <code class="docutils literal"><span class="pre">mx.io.ImageRecordIter</span></code> have multi-label support for a single image.
 For example, if you have four labels for a single image, you can use the following procedure to use the RecordIO tools.</p>
 <ol class="simple">
 <li>Write the image list files as follows:</li>
 </ol>
 <div class="highlight-python"><div class="highlight"><pre><span></span>integer_image_index \t label_1 \t label_2 \t   label_3 \t label_4 \t path_to_image
 </pre></div>
 </div>
 <ol class="simple">
 <li>Run <code class="docutils literal"><span class="pre">im2rec</span></code>, adding a ‘label_width=4’ to the command argument, for example:</li>
 </ol>
 <div class="highlight-bash"><div class="highlight"><pre><span></span>./bin/im2rec image.lst image_root_dir output.bin <span class="nv">resize</span><span class="o">=</span><span class="m">256</span> <span class="nv">label_width</span><span class="o">=</span><span class="m">4</span>
 </pre></div>
 </div>
 <ol class="simple">
 <li>In the iterator generation code, set <code class="docutils literal"><span class="pre">label_width=4</span></code> and <code class="docutils literal"><span class="pre">path_imglist=<<The</span> <span class="pre">PATH</span> <span class="pre">TO</span> <span class="pre">YOUR</span> <span class="pre">image.lst>></span></code>, for example:</li>
 </ol>
 <div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">dataiter</span> <span class="o">=</span> <span class="n">mx</span><span class="o">.</span><span class="n">io</span><span class="o">.</span><span class="n">ImageRecordIter</span><span class="p">(</span>
   <span class="n">path_imgrec</span><span class="o">=</span><span class="s2">"data/cifar/train.rec"</span><span class="p">,</span>
   <span class="n">data_shape</span><span class="o">=</span><span class="p">(</span><span class="mi">3</span><span class="p">,</span><span class="mi">28</span><span class="p">,</span><span class="mi">28</span><span class="p">),</span>
   <span class="n">path_imglist</span><span class="o">=</span><span class="s2">"data/cifar/image.lst"</span><span class="p">,</span>
   <span class="n">label_width</span><span class="o">=</span><span class="mi">4</span>
 <span class="p">)</span>
 </pre></div>
 </div>
 </div>
 </div>
 <div class="container">
 <div class="footer">
 <p> © 2015-2017 DMLC. All rights reserved. </p>
 </div>
 </div>
 </div>
 <div aria-label="main navigation" class="sphinxsidebar rightsidebar" role="navigation">
 <div class="sphinxsidebarwrapper">
 <h3><a href="../index.html">Table Of Contents</a></h3>
 <ul>
 <li><a class="reference internal" href="#">Create a Dataset Using RecordIO</a><ul>
 <li><a class="reference internal" href="#prerequisites">Prerequisites</a></li>
 <li><a class="reference internal" href="#step-1-make-an-image-list-file">Step 1. Make an Image List File</a></li>
 <li><a class="reference internal" href="#step-2-create-the-binary-file">Step 2. Create the Binary File</a></li>
 <li><a class="reference internal" href="#extension-multiple-labels-for-a-single-image">Extension: Multiple Labels for a Single Image</a></li>
 </ul>
 </li>
 </ul>
 </div>
 </div>
 </div> <!-- pagename != index -->
 <script crossorigin="anonymous" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVqOtnepnHVP9aJ7xS" src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
 <script src="../_static/js/sidebar.js" type="text/javascript"></script>
 <script src="../_static/js/search.js" type="text/javascript"></script>
 <script src="../_static/js/navbar.js" type="text/javascript"></script>
 <script src="../_static/js/clipboard.min.js" type="text/javascript"></script>
 <script src="../_static/js/copycode.js" type="text/javascript"></script>
 <script type="text/javascript">
         $('body').ready(function () {
             $('body').css('visibility', 'visible');
         });
     </script>
 </div></body>
 </html>
	<!DOCTYPE html>

	<html lang="en">
	<head>
	<meta charset="utf-8"/>
	<meta content="IE=edge" http-equiv="X-UA-Compatible"/>
	<meta content="width=device-width, initial-scale=1" name="viewport"/>
	<title>Create a Dataset Using RecordIO — mxnet documentation</title>
	<link crossorigin="anonymous" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" rel="stylesheet"/>
	<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css" rel="stylesheet"/>
	<link href="../_static/basic.css" rel="stylesheet" type="text/css">
	<link href="../_static/pygments.css" rel="stylesheet" type="text/css">
	<link href="../_static/mxnet.css" rel="stylesheet" type="text/css"/>
	<script type="text/javascript">
	var DOCUMENTATION_OPTIONS = {
	URL_ROOT: '../',
	VERSION: '',
	COLLAPSE_INDEX: false,
	FILE_SUFFIX: '.html',
	HAS_SOURCE: true,
	SOURCELINK_SUFFIX: ''
	};
	</script>
	<script src="../_static/jquery-1.11.1.js" type="text/javascript"></script>
	<script src="../_static/underscore.js" type="text/javascript"></script>
	<script src="../_static/searchtools_custom.js" type="text/javascript"></script>
	<script src="../_static/doctools.js" type="text/javascript"></script>
	<script src="../_static/selectlang.js" type="text/javascript"></script>
	<script src="https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript"></script>
	<script type="text/javascript"> jQuery(function() { Search.loadIndex("/searchindex.js"); Search.init();}); </script>
	<script>
	(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]\|\|function(){
	(i[r].q=i[r].q\|\|[]).push(arguments)},i[r].l=1*new
	Date();a=s.createElement(o),
	m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
	})(window,document,'script','https://www.google-analytics.com/analytics.js','ga');

	ga('create', 'UA-96378503-1', 'auto');
	ga('send', 'pageview');

	</script>
	<!-- -->
	<!-- <script type="text/javascript" src="../_static/jquery.js"></script> -->
	<!-- -->
	<!-- <script type="text/javascript" src="../_static/underscore.js"></script> -->
	<!-- -->
	<!-- <script type="text/javascript" src="../_static/doctools.js"></script> -->
	<!-- -->
	<!-- <script type="text/javascript" src="https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script> -->
	<!-- -->
	<link href="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/mxnet-icon.png" rel="icon" type="image/png"/>
	</link></link></head>
	<body role="document"><!-- Previous Navbar Layout
	<div class="navbar navbar-default navbar-fixed-top">
	<div class="container">
	<div class="navbar-header">
	<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
	<span class="sr-only">Toggle navigation</span>
	<span class="icon-bar"></span>
	<span class="icon-bar"></span>
	<span class="icon-bar"></span>
	</button>
	<a href="../" class="navbar-brand">
	<img src="http://data.mxnet.io/theme/mxnet.png">
	</a>
	</div>
	<div id="navbar" class="navbar-collapse collapse">
	<ul id="navbar" class="navbar navbar-left">

	<li> <a href="../get_started/index.html">Get Started</a> </li>

	<li> <a href="../tutorials/index.html">Tutorials</a> </li>

	<li> <a href="../how_to/index.html">How To</a> </li>


	<li class="dropdown">
	<a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="true">Packages <span class="caret"></span></a>
	<ul class="dropdown-menu">

	<li><a href="../packages/python/index.html">
	Python
	</a></li>

	<li><a href="../packages/r/index.html">
	R
	</a></li>

	<li><a href="../packages/julia/index.html">
	Julia
	</a></li>

	<li><a href="../packages/c++/index.html">
	C++
	</a></li>

	<li><a href="../packages/scala/index.html">
	Scala
	</a></li>

	<li><a href="../packages/perl/index.html">
	Perl
	</a></li>

	</ul>
	</li>

	<li> <a href="../system/index.html">System</a> </li>
	<li>
	<form class="" role="search" action="../search.html" method="get" autocomplete="off">
	<div class="form-group inner-addon left-addon">
	<i class="glyphicon glyphicon-search"></i>
	<input type="text" name="q" class="form-control" placeholder="Search">
	</div>
	<input type="hidden" name="check_keywords" value="yes" />
	<input type="hidden" name="area" value="default" />

	</form> </li>
	</ul>
	<ul id="navbar" class="navbar navbar-right">
	<li> <a href="../index.html"><span class="flag-icon flag-icon-us"></span></a> </li>
	<li> <a href="..//zh/index.html"><span class="flag-icon flag-icon-cn"></span></a> </li>
	</ul>
	</div>
	</div>
	</div>
	Previous Navbar Layout End -->
	<div class="navbar navbar-fixed-top">
	<div class="container" id="navContainer">
	<div class="innder" id="header-inner">
	<h1 id="logo-wrap">
	<a href="../" id="logo"><img src="http://data.mxnet.io/theme/mxnet.png"/></a>
	</h1>
	<nav class="nav-bar" id="main-nav">
	<a class="main-nav-link" href="../get_started/install.html">Install</a>
	<a class="main-nav-link" href="../tutorials/index.html">Tutorials</a>
	<a class="main-nav-link" href="../how_to/index.html">How To</a>
	<span id="dropdown-menu-position-anchor">
	<a aria-expanded="true" aria-haspopup="true" class="main-nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button">API <span class="caret"></span></a>
	<ul class="dropdown-menu" id="package-dropdown-menu">
	<li><a class="main-nav-link" href="../api/python/index.html">Python</a></li>
	<li><a class="main-nav-link" href="../api/scala/index.html">Scala</a></li>
	<li><a class="main-nav-link" href="../api/r/index.html">R</a></li>
	<li><a class="main-nav-link" href="../api/julia/index.html">Julia</a></li>
	<li><a class="main-nav-link" href="../api/c++/index.html">C++</a></li>
	<li><a class="main-nav-link" href="../api/perl/index.html">Perl</a></li>
	</ul>
	</span>
	<a class="main-nav-link" href="../architecture/index.html">Architecture</a>
	<!-- <a class="main-nav-link" href="../community/index.html">Community</a> -->
	<a class="main-nav-link" href="https://github.com/dmlc/mxnet">Github</a>
	<span id="dropdown-menu-position-anchor-version" style="position: relative"><a href="#" class="main-nav-link dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="true">Versions(master)<span class="caret"></span></a><ul id="package-dropdown-menu" class="dropdown-menu"><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/test/>v0.10.14</a></li><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/test/versions/0.10/index.html>0.10</a></li><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/test/versions/master/index.html>master</a></li></ul></span></nav>
	<script> function getRootPath(){ return "../" } </script>
	<div class="burgerIcon dropdown">
	<a class="dropdown-toggle" data-toggle="dropdown" href="#" role="button">☰</a>
	<ul class="dropdown-menu dropdown-menu-right" id="burgerMenu">
	<li><a href="../get_started/install.html">Install</a></li>
	<li><a href="../tutorials/index.html">Tutorials</a></li>
	<li><a href="../how_to/index.html">How To</a></li>
	<li class="dropdown-submenu">
	<a href="#" tabindex="-1">API</a>
	<ul class="dropdown-menu">
	<li><a href="../api/python/index.html" tabindex="-1">Python</a>
	</li>
	<li><a href="../api/scala/index.html" tabindex="-1">Scala</a>
	</li>
	<li><a href="../api/r/index.html" tabindex="-1">R</a>
	</li>
	<li><a href="../api/julia/index.html" tabindex="-1">Julia</a>
	</li>
	<li><a href="../api/c++/index.html" tabindex="-1">C++</a>
	</li>
	<li><a href="../api/perl/index.html" tabindex="-1">Perl</a>
	</li>
	</ul>
	</li>
	<li><a href="../architecture/index.html">Architecture</a></li>
	<li><a class="main-nav-link" href="https://github.com/dmlc/mxnet">Github</a></li>
	<li id="dropdown-menu-position-anchor-version-mobile" class="dropdown-submenu" style="position: relative"><a href="#" tabindex="-1">Versions(master)</a><ul class="dropdown-menu"><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/test/>v0.10.14</a></li><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/test/versions/0.10/index.html>0.10</a></li><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/test/versions/master/index.html>master</a></li></ul></li></ul>
	</div>
	<div class="plusIcon dropdown">
	<a class="dropdown-toggle" data-toggle="dropdown" href="#" role="button"><span aria-hidden="true" class="glyphicon glyphicon-plus"></span></a>
	<ul class="dropdown-menu dropdown-menu-right" id="plusMenu"></ul>
	</div>
	<div id="search-input-wrap">
	<form action="../search.html" autocomplete="off" class="" method="get" role="search">
	<div class="form-group inner-addon left-addon">
	<i class="glyphicon glyphicon-search"></i>
	<input class="form-control" name="q" placeholder="Search" type="text"/>
	</div>
	<input name="check_keywords" type="hidden" value="yes">
	<input name="area" type="hidden" value="default"/>
	</input></form>
	<div id="search-preview"></div>
	</div>
	<div id="searchIcon">
	<span aria-hidden="true" class="glyphicon glyphicon-search"></span>
	</div>
	<!-- <div id="lang-select-wrap"> -->
	<!-- <label id="lang-select-label"> -->
	<!-- <\!-- <i class="fa fa-globe"></i> -\-> -->
	<!-- <span></span> -->
	<!-- </label> -->
	<!-- <select id="lang-select"> -->
	<!-- <option value="en">Eng</option> -->
	<!-- <option value="zh">中文</option> -->
	<!-- </select> -->
	<!-- </div> -->
	<!-- <a id="mobile-nav-toggle">
	<span class="mobile-nav-toggle-bar"></span>
	<span class="mobile-nav-toggle-bar"></span>
	<span class="mobile-nav-toggle-bar"></span>
	</a> -->
	</div>
	</div>
	</div>
	<div class="container">
	<div class="row">
	<div aria-label="main navigation" class="sphinxsidebar leftsidebar" role="navigation">
	<div class="sphinxsidebarwrapper">
	<ul>
	<li class="toctree-l1"><a class="reference internal" href="../api/python/index.html">Python Documents</a></li>
	<li class="toctree-l1"><a class="reference internal" href="../api/r/index.html">R Documents</a></li>
	<li class="toctree-l1"><a class="reference internal" href="../api/julia/index.html">Julia Documents</a></li>
	<li class="toctree-l1"><a class="reference internal" href="../api/c++/index.html">C++ Documents</a></li>
	<li class="toctree-l1"><a class="reference internal" href="../api/scala/index.html">Scala Documents</a></li>
	<li class="toctree-l1"><a class="reference internal" href="../api/perl/index.html">Perl Documents</a></li>
	<li class="toctree-l1"><a class="reference internal" href="index.html">HowTo Documents</a></li>
	<li class="toctree-l1"><a class="reference internal" href="../architecture/index.html">System Documents</a></li>
	<li class="toctree-l1"><a class="reference internal" href="../tutorials/index.html">Tutorials</a></li>
	</ul>
	</div>
	</div>
	<div class="content">
	<div class="section" id="create-a-dataset-using-recordio">
	<span id="create-a-dataset-using-recordio"></span><h1>Create a Dataset Using RecordIO<a class="headerlink" href="#create-a-dataset-using-recordio" title="Permalink to this headline">¶</a></h1>
	<p>RecordIO implements a file format for a sequence of records. We recommend storing images as records and packing them together. The benefits include:</p>
	<ul class="simple">
	<li>Storing images in a compact format–e.g., JPEG, for records–greatly reduces the size of the dataset on the disk.</li>
	<li>Packing data together allows continuous reading on the disk.</li>
	<li>RecordIO has a simple way to partition, simplifying distributed setting. We provide an example later.</li>
	</ul>
	<p>We provide the <a class="reference external" href="https://github.com/dmlc/mxnet/blob/master/tools/im2rec.cc">im2rec tool</a> so you can create an Image RecordIO dataset by yourself. The following walkthrough shows you how.</p>
	<div class="section" id="prerequisites">
	<span id="prerequisites"></span><h2>Prerequisites<a class="headerlink" href="#prerequisites" title="Permalink to this headline">¶</a></h2>
	<p>Download the data. You don’t need to resize the images manually. You can use <code class="docutils literal"><span class="pre">im2rec</span></code> to resize them automatically. For details, see the “Extension: Using Multiple Labels for a Single Image,” later in this topic.</p>
	</div>
	<div class="section" id="step-1-make-an-image-list-file">
	<span id="step-1-make-an-image-list-file"></span><h2>Step 1. Make an Image List File<a class="headerlink" href="#step-1-make-an-image-list-file" title="Permalink to this headline">¶</a></h2>
	<p>After you download the data, you need to make an image list file. The format is:</p>
	<div class="highlight-python"><div class="highlight"><pre><span></span>integer_image_index \t label_index \t path_to_image
	</pre></div>
	</div>
	<p>Typically, the program takes the list of names of all of the images, shuffles them, then separates them into two lists: a training filename list and a testing filename list. Write the list in the right format.</p>
	<p>This is an example file:</p>
	<div class="highlight-bash"><div class="highlight"><pre><span></span><span class="m">95099</span> <span class="m">464</span> n04467665_17283.JPEG
	<span class="m">10025081</span> <span class="m">412</span> ILSVRC2010_val_00025082.JPEG
	<span class="m">74181</span> <span class="m">789</span> n01915811_2739.JPEG
	<span class="m">10035553</span> <span class="m">859</span> ILSVRC2010_val_00035554.JPEG
	<span class="m">10048727</span> <span class="m">929</span> ILSVRC2010_val_00048728.JPEG
	<span class="m">94028</span> <span class="m">924</span> n01980166_4956.JPEG
	<span class="m">1080682</span> <span class="m">650</span> n11807979_571.JPEG
	<span class="m">972457</span> <span class="m">633</span> n07723039_1627.JPEG
	<span class="m">7534</span> <span class="m">11</span> n01630670_4486.JPEG
	<span class="m">1191261</span> <span class="m">249</span> n12407079_5106.JPEG
	</pre></div>
	</div>
	</div>
	<div class="section" id="step-2-create-the-binary-file">
	<span id="step-2-create-the-binary-file"></span><h2>Step 2. Create the Binary File<a class="headerlink" href="#step-2-create-the-binary-file" title="Permalink to this headline">¶</a></h2>
	<p>To generate a binary image, use <code class="docutils literal"><span class="pre">im2rec</span></code> in the tool folder. <code class="docutils literal"><span class="pre">im2rec</span></code> takes the path of the <code class="docutils literal"><span class="pre">_image</span> <span class="pre">list</span> <span class="pre">file_</span></code> you generated, the <code class="docutils literal"><span class="pre">_root</span> <span class="pre">path_</span></code> of the images, and the <code class="docutils literal"><span class="pre">_output</span> <span class="pre">file</span> <span class="pre">path_</span></code> as input. This process usually takes several hours, so be patient.</p>
	<p>Sample command:</p>
	<div class="highlight-bash"><div class="highlight"><pre><span></span>./bin/im2rec image.lst image_root_dir output.bin <span class="nv">resize</span><span class="o">=</span><span class="m">256</span>
	</pre></div>
	</div>
	<p>For more details, run <code class="docutils literal"><span class="pre">./bin/im2rec</span></code>.</p>
	</div>
	<div class="section" id="extension-multiple-labels-for-a-single-image">
	<span id="extension-multiple-labels-for-a-single-image"></span><h2>Extension: Multiple Labels for a Single Image<a class="headerlink" href="#extension-multiple-labels-for-a-single-image" title="Permalink to this headline">¶</a></h2>
	<p>The <code class="docutils literal"><span class="pre">im2rec</span></code> tool and <code class="docutils literal"><span class="pre">mx.io.ImageRecordIter</span></code> have multi-label support for a single image.
	For example, if you have four labels for a single image, you can use the following procedure to use the RecordIO tools.</p>
	<ol class="simple">
	<li>Write the image list files as follows:</li>
	</ol>
	<div class="highlight-python"><div class="highlight"><pre><span></span>integer_image_index \t label_1 \t label_2 \t label_3 \t label_4 \t path_to_image
	</pre></div>
	</div>
	<ol class="simple">
	<li>Run <code class="docutils literal"><span class="pre">im2rec</span></code>, adding a ‘label_width=4’ to the command argument, for example:</li>
	</ol>
	<div class="highlight-bash"><div class="highlight"><pre><span></span>./bin/im2rec image.lst image_root_dir output.bin <span class="nv">resize</span><span class="o">=</span><span class="m">256</span> <span class="nv">label_width</span><span class="o">=</span><span class="m">4</span>
	</pre></div>
	</div>
	<ol class="simple">
	<li>In the iterator generation code, set <code class="docutils literal"><span class="pre">label_width=4</span></code> and <code class="docutils literal"><span class="pre">path_imglist=<<The</span> <span class="pre">PATH</span> <span class="pre">TO</span> <span class="pre">YOUR</span> <span class="pre">image.lst>></span></code>, for example:</li>
	</ol>
	<div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">dataiter</span> <span class="o">=</span> <span class="n">mx</span><span class="o">.</span><span class="n">io</span><span class="o">.</span><span class="n">ImageRecordIter</span><span class="p">(</span>
	<span class="n">path_imgrec</span><span class="o">=</span><span class="s2">"data/cifar/train.rec"</span><span class="p">,</span>
	<span class="n">data_shape</span><span class="o">=</span><span class="p">(</span><span class="mi">3</span><span class="p">,</span><span class="mi">28</span><span class="p">,</span><span class="mi">28</span><span class="p">),</span>
	<span class="n">path_imglist</span><span class="o">=</span><span class="s2">"data/cifar/image.lst"</span><span class="p">,</span>
	<span class="n">label_width</span><span class="o">=</span><span class="mi">4</span>
	<span class="p">)</span>
	</pre></div>
	</div>
	</div>
	</div>
	<div class="container">
	<div class="footer">
	<p> © 2015-2017 DMLC. All rights reserved. </p>
	</div>
	</div>
	</div>
	<div aria-label="main navigation" class="sphinxsidebar rightsidebar" role="navigation">
	<div class="sphinxsidebarwrapper">
	<h3><a href="../index.html">Table Of Contents</a></h3>
	<ul>
	<li><a class="reference internal" href="#">Create a Dataset Using RecordIO</a><ul>
	<li><a class="reference internal" href="#prerequisites">Prerequisites</a></li>
	<li><a class="reference internal" href="#step-1-make-an-image-list-file">Step 1. Make an Image List File</a></li>
	<li><a class="reference internal" href="#step-2-create-the-binary-file">Step 2. Create the Binary File</a></li>
	<li><a class="reference internal" href="#extension-multiple-labels-for-a-single-image">Extension: Multiple Labels for a Single Image</a></li>
	</ul>
	</li>
	</ul>
	</div>
	</div>
	</div> <!-- pagename != index -->
	<script crossorigin="anonymous" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVqOtnepnHVP9aJ7xS" src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
	<script src="../_static/js/sidebar.js" type="text/javascript"></script>
	<script src="../_static/js/search.js" type="text/javascript"></script>
	<script src="../_static/js/navbar.js" type="text/javascript"></script>
	<script src="../_static/js/clipboard.min.js" type="text/javascript"></script>
	<script src="../_static/js/copycode.js" type="text/javascript"></script>
	<script type="text/javascript">
	$('body').ready(function () {
	$('body').css('visibility', 'visible');
	});
	</script>
	</div></body>
	</html>