title: ffmpeg: AVI to FLV conversion doubles file size
body: <p>I convert AVI to FLV with ffmpeg using -sameq parameter (same quality):</p>
  
  <pre><code>ffmpeg -i test.avi -sameq -f flv sameq.flv
  </code></pre>
  
  <p>The resulting file has the same video and audio quality as the original, but it's more than twice the original file size:</p>
  
  <pre><code>84M sameq.flv
  41M test.avi
  </code></pre>
  
  <p>Why does it happen?</p>
  
  <p>Transcoder output:</p>
  
  <pre><code>ffmpeg version N-34750-g070d2d7, Copyright (c) 2000-2011 the FFmpeg developers
    built on Nov 12 2011 11:23:07 with gcc 4.6.1
    configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-x11grab
    libavutil    51. 24. 1 / 51. 24. 1
    libavcodec   53. 33. 0 / 53. 33. 0
    libavformat  53. 20. 0 / 53. 20. 0
    libavdevice  53.  4. 0 / 53.  4. 0
    libavfilter   2. 48. 0 /  2. 48. 0
    libswscale    2.  1. 0 /  2.  1. 0
    libpostproc  51.  2. 0 / 51.  2. 0
  Input #0, avi, from 'test.avi':
    Duration: 00:06:30.00, start: 0.000000, bitrate: 866 kb/s
      Stream #0:0: Video: mpeg4 (Advanced Real Time Simple Profile) (DIVX / 0x58564944), yuv420p, 400x300 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
      Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 44100 Hz, mono, s16, 64 kb/s
  [buffer @ 0xa247ae0] w:400 h:300 pixfmt:yuv420p tb:1/1000000 sar:1/1 sws_param:
  Output #0, flv, to 'sameq.flv':
    Metadata:
      encoder         : Lavf53.20.0
      Stream #0:0: Video: flv1 ([2][0][0][0] / 0x0002), yuv420p, 400x300 [SAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 1k tbn, 25 tbc
      Stream #0:1: Audio: mp3 ([2][0][0][0] / 0x0002), 44100 Hz, mono, s16, 128 kb/s
  Stream mapping:
    Stream #0:0 -&gt; #0:0 (mpeg4 -&gt; flv)
    Stream #0:1 -&gt; #0:1 (mp3 -&gt; libmp3lame)
  Press [q] to stop, [?] for help
  frame= 9742 fps=255 q=0.0 Lsize=   85074kB time=00:06:30.00 bitrate=1787.0kbits/s    
  video:79163kB audio:5525kB global headers:0kB muxing overhead 0.455568%
  </code></pre>