title: conversion from mp3 to ogg using php
body: <p>I want to convert mp3 file to ogg. I tried the following code</p>
  
  <pre><code>exec("/usr/local/bin/ffmpeg -i 1.mp4 -vcodec libtheora -acodec libvorbis testjohn4545454.ogg",$output);
  var_dump($output);
  </code></pre>
  
  <p>But it does not convert the file and it only returns <code>array(0) { }</code>
  and it only takes a little execution time.</p>
  
  <p>But the conversion is success when using ssh command.</p>
  
  <p>Please give me solution.</p>