title: FFMPEG ignores bitrate
body: <p>I am new to video encoding so bear with me.</p>
  
  <p>I am using FFMPEG. I have an mp4 file which is 640 x 350 with an average bitrate of around 2000kb (I think) and a filesize of 80Mb. I want to convert this to an ogv file with a much lower bit rate (128kb) but the same width and height. I am using the following command...</p>
  
  <pre><code>ffmpeg -i input.mp4 -b:v 128k output.ogv
  </code></pre>
  
  <p>... but FFMPEG seems to ignore my bitrate option and outputs a file with a bitrate of around 600kb and a filesize of around 3Mb.</p>
  
  <p>I can do this using FFMPEG2THEORA using the following command ... </p>
  
  <pre><code>ffmpeg2theora -V 128 input.mp4 -o output.ogv
  </code></pre>
  
  <p>...but I was wondering if it was possible using FFMPEG.</p>
  
  <p>Any ideas?</p>
  
  <h1>Edit</h1>
  
  <p>mark4o solved my problem. It turns out that the default audio codec was bumping up the filesize. Changing it to libvorbis has reduced the filesize dramatically. Final command looks like</p>
  
  <pre><code>ffmpeg -i input.mp4 -b:v 128k -b:a 128k -codec:a libvorbis output128.ogv
  </code></pre>
  
  <ul>
  <li><code>-i</code> = input file</li>
  <li><code>-b:v</code> = the bitrate of the video stream</li>
  <li><code>-b:a</code> = the bitrate of the audio stream</li>
  <li><code>-codec:a</code> = override the default audio codec</li>
  </ul>