title: Convert a video to MP4 (H.264/AAC) with ffmpeg
body: <p>If I don't make a mistake, Safari currently need MP4 (H.264/AAC) video encoded for the HTML5 <code>&lt;video&gt;</code> element.</p>
  
  <p>So I tried to convert a video to this format with <code>ffmpeg</code>. However when I enter the shell command <code>ffmpeg -i video.flv video.mp4</code>, the returned error is :</p>
  
  <blockquote>
    <p>Seems stream 0 codec frame rate
    differs from container frame rate:
    2000.00 (2000/1) -> 29.92 (359/12) Input #0, flv, from 'video.flv':<br>
    Duration: 00:05:01.20, start:
    0.000000, bitrate: 66 kb/s
        Stream #0.0: Video: h264, yuv420p, 320x240 [PAR 1:1 DAR 4:3], 66 kb/s,
    29.92 tbr, 1k tbn, 2k tbc
        Stream #0.1: Audio: aac, 22050 Hz, stereo, s16 Output #0, mp4, to
    'video.mp4':
        Stream #0.0: Video: mpeg4, yuv420p, 320x240 [PAR 1:1 DAR 4:3],
    q=2-31, 200 kb/s, 90k tbn, 29.92 tbc
        Stream #0.1: Audio: 0x0000, 22050 Hz, stereo, s16, 64 kb/s Stream
    mapping:   Stream #0.0 -> #0.0<br>
    Stream #0.1 -> #0.1 Unsupported codec
    for output stream #0.1</p>
  </blockquote>
  
  <p>An AAC codec is required but I'm quite newbie with ubuntu and I dont really now how to fix this problem. I'm using Ubuntu 9.10 Karmik Koala (for amd64).</p>
  
  <p>Thank you very much. :)</p>