title: Unknown encoder 'libx264'
body: <p>I installed ffmpeg 0.8.9 on ubuntu11 by </p>
  
  <blockquote>
    <p>./configure --enable-gpl --enable-nonfree --enable-pthreads
    --enable-libfaac --enable-libmp3lame --enable-libx264</p>
  </blockquote>
  
  <p>When I run it</p>
  
  <pre><code>ffmpeg -y -i test.mp4 -f mpegts -acodec libmp3lame -ar 48000 -ab 64k -vcodec libx264 -b 250k -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -subq 5 -trellis 1 -refs 1 -coder 0 -me_range 16 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 250k -maxrate 250k -bufsize 250k -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -level 30 -aspect 320:240 -g 30 -async 2 a.ts
  </code></pre>
  
  <p>It said</p>
  
  <blockquote>
    <p>Unknown encoder 'libx264'</p>
  </blockquote>
  
  <p>(Note: the same error could occour with <code>avconv</code>)</p>
  
  <p>How can I fix this? Thanks!</p>