title: fluent ffmpeg size output option not working
body: <p>Summary: I'm trying to limit output to 3mb, <code>.outputOptions('-fs 3000000')</code> isn't working for me, the file is coming back with a size of <code>119260428</code> or 119mb.</p>
  
  <p>Here is the code to try for yourself, all you need is a <code>test.mp3</code> large enough that the resulting <code>testoutput.ogg</code> is > 3mb:</p>
  
  <pre><code>var ffmpeg = require("fluent-ffmpeg");
  var command = ffmpeg();
  
  var convertToOGG = function(){
    var fileName = 'test.mp3'
  
    ffmpeg.ffprobe(fileName, function(err, metadata) {
      command
        .input(fileName)
        .inputFormat("mp3")
        .audioChannels(1)
        .outputOptions('-fs', 3000000)
        .output('testoutput.ogg')
        .on("progress", function(progress) {
          console.log("Processing: " + progress.timemark);
        })
        .on("error", function(err, stdout, stderr) {
          console.log("Cannot process video: " + err.message);
        })
        .on("end", function(stdout, stderr) {
          ffmpeg.ffprobe('testoutput.ogg', function(err,metadata){
            if(metadata.format.size &gt;= 3000000){
  
              console.log("didn't work")
            } 
          })
        })
      .run();
    });
  };
  
  convertToOGG();
  </code></pre>
  
  <p>Per the <a href="https://github.com/fluent-ffmpeg/node-fluent-ffmpeg" rel="nofollow noreferrer">fluent-ffmpeg documentation</a> you should be able to use a ffmpeg command in an output option: <code>outputOption()</code></p>
  
  <blockquote>
    <p>This method allows passing any output-related option to ffmpeg. You can call it with a single argument to pass a single option, optionnaly
    with a space-separated parameter:</p>
  </blockquote>
  
  <pre><code>/* Single option */
  ffmpeg('/path/to/file.avi').outputOptions('-someOption');
  </code></pre>
  
  <p><a href="https://ffmpeg.org/ffmpeg.html" rel="nofollow noreferrer">and in FFMPEG's documentation</a>:</p>
  
  <blockquote>
    <p>-fs limit_size (output) Set the file size limit, expressed in bytes. No further chunk of bytes is written after the limit is exceeded. The
    size of the output file is slightly more than the requested file size.</p>
  </blockquote>
  
  <p>It's giving me no errors, just seemingly ignoring the file size limit of 99mb and outputting a 119.3mb file.</p>
  
  <p>Edit - Looks like <code>-fs 3000000</code> is working for mp3 to wav, but still wont do mp3 to ogg.  This is the output from running the command in terminal:</p>
  
  <pre><code>✗ ffmpeg -i test.mp3 -fs 3000000 testoutput.ogg
  ffmpeg version 3.2.2 Copyright (c) 2000-2016 the FFmpeg developers
    built with Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn)
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.2.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
    libavutil      55. 34.100 / 55. 34.100
    libavcodec     57. 64.101 / 57. 64.101
    libavformat    57. 56.100 / 57. 56.100
    libavdevice    57.  1.100 / 57.  1.100
    libavfilter     6. 65.100 /  6. 65.100
    libavresample   3.  1.  0 /  3.  1.  0
    libswscale      4.  2.100 /  4.  2.100
    libswresample   2.  3.100 /  2.  3.100
    libpostproc    54.  1.100 / 54.  1.100
  [mp3 @ 0x7fc6a4000000] Estimating duration from bitrate, this may be inaccurate
  Input #0, mp3, from 'test.mp3':
    Metadata:
      lyrics-eng      : xxx
      title           : xxx
      artist          : xxx
      album_artist    : xxx
      album           : xxx
      genre           : xxx
    Duration: 03:27:28.74, start: 0.000000, bitrate: 128 kb/s
      Stream #0:0: Audio: mp3, 44100 Hz, mono, s16p, 128 kb/s
      Stream #0:1: Video: mjpeg, yuvj444p(pc, bt470bg/unknown/unknown), 540x360, 90k tbr, 90k tbn, 90k tbc
      Metadata:
        title           : Array
        comment         : Cover (front)
  [swscaler @ 0x7fc6a4808800] deprecated pixel format used, make sure you did set range correctly
  [ogg @ 0x7fc6a3815800] Frame rate very high for a muxer not efficiently supporting it.
  Please consider specifying a lower framerate, a different muxer or -vsync 2
  Output #0, ogg, to 'testoutput.ogg':
    Metadata:
      lyrics-eng      : xxx
      title           : xxx
      artist          : xxx
      album_artist    : xxx
      album           : xxx
      genre           : xxx
      encoder         : Lavf57.56.100
      Stream #0:0: Video: theora (libtheora), yuv444p, 540x360, q=2-31, 200 kb/s, 90k fps, 90k tbn, 90k tbc
      Metadata:
        title           : Array
        DESCRIPTION     : Cover (front)
        encoder         : Lavc57.64.101 libtheora
        lyrics-eng      : xxx
        artist          : xxx
        ALBUMARTIST     : xxx
        album           : xxx
        genre           : xxx
      Stream #0:1: Audio: vorbis (libvorbis), 44100 Hz, mono, fltp
      Metadata:
        encoder         : Lavc57.64.101 libvorbis
        lyrics-eng      : xxx
        title           : xxx
        artist          : xxx
        ALBUMARTIST     : xxx
        album           : xxx
        genre           : xxx
  Stream mapping:
    Stream #0:1 -&gt; #0:0 (mjpeg (native) -&gt; theora (libtheora))
    Stream #0:0 -&gt; #0:1 (mp3 (native) -&gt; vorbis (libvorbis))
  Press [q] to stop, [?] for help
  frame=    1 fps=0.0 q=-0.0 Lsize=  116465kB time=03:27:28.71 bitrate=  76.6kbits/s speed=61.2x
  video:9kB audio:114907kB subtitle:0kB other streams:0kB global headers:6kB muxing overhead: 1.347787%
  </code></pre>