title: Can I dynamically call a LGPL/GPL software in my closed-source application?
body: <p>I want to use a tool (<a href="http://ffmpeg.org/legal.html" rel="noreferrer">ffmpeg</a>) that is under <a href="http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html" rel="noreferrer">GNU Lesser General Public License, version 2.1</a> <a href="http://www.gnu.org/licenses/old-licenses/gpl-2.0.html" rel="noreferrer">GNU General Public License (GPL) version 2</a> for some components.</p>
  
  <p>To do so, I only call it in my software as such:</p>
  
  <pre><code>System.Diagnostics.Process p = new System.Diagnostics.Process();
  p.StartInfo = new System.Diagnostics.ProcessStartInfo("lgplSoftware.exe", myParams);
  p.Start();
  </code></pre>
  
  <p>I do not change it, I only use a built version of the software for windows.</p>
  
  <hr>
  
  <p><a href="http://en.wikipedia.org/wiki/GNU_General_Public_License" rel="noreferrer">Wikipedia</a> says:</p>
  
  <blockquote>
    <p>A key dispute related to the GPL is
    whether or not non-GPL software can be
    dynamically linked to GPL libraries.
    The GPL is clear in requiring that all
    derivative works of code under the GPL
    must themselves be under the GPL.
    While it is understood that static
    linking produces derivative works, it
    is not clear whether an executable
    that dynamically links to a GPL code
    should be considered a derivative work
    (see Weak Copyleft). The
    free/open-source software community is
    split on this issue. The FSF asserts
    that such an executable is indeed a
    derivative work if the executable and
    GPL code "make function calls to each
    other and share data structures,"
    with certain others agreeing (e.g.
    Jerry Epplin), while some (e.g.
    Linus Torvalds) agree that dynamic
    linking can create derived works but
    disagree over the circumstances.</p>
  </blockquote>
  
  <hr>
  
  <p>I am really confused by all this legal things. I would have made my project LGPL as well and released the source, but this is not up to me. </p>
  
  <p>So the question is: can I use it like I'm doing right now or will I be executed by an army of lawyers?</p>