blog/archive/2009/04/index.html

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
   2         "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
   3 <html>
   4  <head>
   5   <title>Petter Reinholdtsen: entries from April 2009</title>
   6   <link rel="stylesheet" type="text/css" media="screen" href="../../../style.css">
   7   <link rel="alternate" title="RSS Feed" href="04.rss" type="application/rss+xml">
   8  </head>
   9  <body>
  10 <!-- XML FEED -->
  11
  12  <div class="title">
  13   <h1>
  14        <a href="../../../">Petter Reinholdtsen</a>
  15
  16   </h1>
  17
  18  </div>
  19
  20  <p>Entries from April 2009.</p>
  21
  22
  23 <div class="entry">
  24  <div class="title">
  25  <a href="../../../Recording_video_from_cron_using_VLC.html">Recording video from cron using VLC</a>
  26  </div>
  27  <div class="date">
  28   2009-04-05 10:00
  29  </div>
  30
  31  <div class="body">
  32
  33 <p>One think I have wanted to figure out for a along time is how to
  34 run vlc from cron to do recording of video streams on the net.  The
  35 task is trivial with mplayer, but I do not really trust the security
  36 of mplayer (it crashes too often on strange input), and thus prefer
  37 vlc.  I finally found a way to do it today.  I spent an hour or so
  38 searching the web for recipes and reading the documentation.  The
  39 hardest part was to get rid of the GUI window, but after finding the
  40 dummy interface, the command line finally presented itself:</p>
  41
  42 <blockquote><pre>URL=http://www.ping.uio.no/video/rms-oslo_2009.ogg
  43 SAVEFILE=rms.ogg
  44 DISPLAY= vlc -q $URL \
  45   --sout="#duplicate{dst=std{access=file,url='$SAVEFILE'},dst=nodisplay}" \
  46   --intf=dummy</pre></blockquote>
  47
  48 <p>The command stream the URL and store it in the SAVEFILE by
  49 duplicating the output stream to "nodisplay" and the file, using the
  50 dummy interface.  The dummy interface and the nodisplay output make
  51 sure no X interface is needed.</p>
  52
  53 <p>The cron job then need to start this job with the appropriate URL
  54 and file name to save, sleep for the duration wanted, and then kill
  55 the vlc process with SIGTERM.  Here is a complete script
  56 <tt>vlc-record</tt> to use from <tt>at</tt> or <tt>cron</tt>:</p>
  57
  58 <blockquote><pre>#!/bin/sh
  59 set -e
  60 URL="$1"
  61 SAVEFILE="$2"
  62 DURATION="$3"
  63 DISPLAY= vlc -q "$URL" \
  64   --sout="#duplicate{dst=std{access=file,url='$SAVEFILE'},dst=nodisplay}" \
  65   --intf=dummy < /dev/null > /dev/null 2>&1 &
  66 pid=$!
  67 sleep $DURATION
  68 kill $pid
  69 wait $pid</pre></blockquote>
  70
  71  </div>
  72  <div class="tags">
  73
  74
  75
  76   Tags: <a href="../../../tags/english">english</a>, <a href="../../../tags/nuug">nuug</a>, <a href="../../../tags/video">video</a>.
  77
  78  </div>
  79 </div>
  80  <div class="padding"></div>
  81
  82  <p style="text-align: right;"><a href="04.rss"><img src="../../../xml.gif" alt="RSS Feed" width="36" height="14"></a></p>
  83
  84
  85
  86 <div id="sidebar">
  87
  88 <h2>Archive</h2>
  89 <ul>
  90
  91 <li>2009
  92 <ul>
  93
  94 <li><a href="../../../archive/2009/01/">January (8)</a></li>
  95
  96 <li><a href="../../../archive/2009/02/">February (8)</a></li>
  97
  98 <li><a href="../../../archive/2009/03/">March (12)</a></li>
  99
 100 <li><a href="../../../archive/2009/04/">April (1)</a></li>
 101
 102 </ul></li>
 103
 104 <li>2008
 105 <ul>
 106
 107 <li><a href="../../../archive/2008/11/">November (5)</a></li>
 108
 109 <li><a href="../../../archive/2008/12/">December (7)</a></li>
 110
 111 </ul></li>
 112
 113 </ul>
 114
 115
 116
 117 <h2>Tags</h2>
 118 <ul>
 119
 120  <li><a href="../../../tags/3d-printer">3d-printer (9)</a></li>
 121
 122  <li><a href="../../../tags/amiga">amiga (1)</a></li>
 123
 124  <li><a href="../../../tags/aros">aros (1)</a></li>
 125
 126  <li><a href="../../../tags/debian">debian (6)</a></li>
 127
 128  <li><a href="../../../tags/debian edu">debian edu (6)</a></li>
 129
 130  <li><a href="../../../tags/english">english (10)</a></li>
 131
 132  <li><a href="../../../tags/fiksgatami">fiksgatami (1)</a></li>
 133
 134  <li><a href="../../../tags/ltsp">ltsp (1)</a></li>
 135
 136  <li><a href="../../../tags/multimedia">multimedia (2)</a></li>
 137
 138  <li><a href="../../../tags/norsk">norsk (31)</a></li>
 139
 140  <li><a href="../../../tags/nuug">nuug (31)</a></li>
 141
 142  <li><a href="../../../tags/personvern">personvern (3)</a></li>
 143
 144  <li><a href="../../../tags/reprap">reprap (9)</a></li>
 145
 146  <li><a href="../../../tags/rss">rss (1)</a></li>
 147
 148  <li><a href="../../../tags/standard">standard (2)</a></li>
 149
 150  <li><a href="../../../tags/stavekontroll">stavekontroll (1)</a></li>
 151
 152  <li><a href="../../../tags/video">video (6)</a></li>
 153
 154  <li><a href="../../../tags/vitenskap">vitenskap (1)</a></li>
 155
 156  <li><a href="../../../tags/web">web (2)</a></li>
 157
 158 </ul>
 159
 160 </div>
 161 </body>
 162 </html>