title: unknown encoder libvo_aacenc
body: <p>i am trying to convert a .mov file to an mp4 file using the following command.</p>
  
  <pre><code>ffmpeg -i sample_iTunes.mov -c:v libx264 -vb 800k -c:a libvo_aacenc -ab 128k -ac 2 test.mp4
  </code></pre>
  
  <p>When i run this i get the following error:</p>
  
  <blockquote>
    <p>Unknown encoder 'libvo_aacenc'</p>
  </blockquote>
  
  <p>So i attempted to install the following:</p>
  
  <pre><code>sudo apt-get install libavcodec-extra
  </code></pre>
  
  <p>However sadly im still getting the error.</p>
  
  <p>Can anyone help me out here?</p>
  
  <p><strong>aergistal answer</strong></p>
  
  <p>Here are the log from the things youve asked me to check:</p>
  
  <p>My operation system is <code>ubuntu 14.04</code></p>
  
  <p>output of <code>ffmpeg -codecs | grep aac</code>:</p>
  
  <pre><code>    ffmpeg version 2.4.3-1ubuntu1~trusty6 Copyright (c) 2000-2014 the FFmpeg developers
    built on Nov 22 2014 17:07:19 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
    configuration: --prefix=/usr --extra-version='1ubuntu1~trusty6' --build-suffix=-ffmpeg --toolchain=hardened --extra-cflags= --extra-cxxflags= --libdir=/usr/lib/x86_64-linux-gnu --shlibdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --enable-shared --disable-stripping --enable-avresample --enable-avisynth --enable-fontconfig --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-opengl --enable-x11grab --enable-libxvid --enable-libx265 --enable-libdc1394 --enable-libiec61883 --enable-libzvbi --enable-libzmq --enable-frei0r --enable-libx264 --enable-libsoxr --enable-openal --enable-libopencv
    libavutil      54.  7.100 / 54.  7.100
    libavcodec     56.  1.100 / 56.  1.100
    libavformat    56.  4.101 / 56.  4.101
    libavdevice    56.  0.100 / 56.  0.100
    libavfilter     5.  1.100 /  5.  1.100
    libavresample   2.  1.  0 /  2.  1.  0
    libswscale      3.  0.100 /  3.  0.100
    libswresample   1.  1.100 /  1.  1.100
    libpostproc    53.  0.100 / 53.  0.100
   DEA.L. aac                  AAC (Advanced Audio Coding)
   D.A.L. aac_latm             AAC LATM (Advanced Audio Coding LATM syntax)
  </code></pre>
  
  <p>out put of:</p>
  
  <pre><code>avconv -codecs | grep aac
  </code></pre>
  
  <p>is:</p>
  
  <pre><code>    avconv version 9.18-6:9.18-0ubuntu0.14.04.1, Copyright (c) 2000-2014 the Libav developers
    built on Mar 16 2015 13:19:10 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
  DEA.L. aac                  AAC (Advanced Audio Coding) (encoders: aac libvo_aacenc )
  D.A.L. aac_latm             AAC LATM (Advanced Audio Coding LATM syntax)
  </code></pre>
  
  <p>I still get the same error.</p>