title: How to remove ALL metadata using ffmpeg?
body: <p>I have input file: <code>infile.mp3</code><br />
  This file contains metadata (artist, genre, etc.)<br />
  I try remove all metadata to output a <code>.wav</code> file.</p>
  <p>Yes! I found option:</p>
  <blockquote>
  <p>-map_metadata -1</p>
  </blockquote>
  <p>But output is unexpected to me...</p>
  <pre><code>$ ffmpeg -i infile.mp3 -acodec pcm_s16le -ac 2 \
                  -ar 44100 -map_metadata -1 ./outfile.wav
  </code></pre>
  <p>OK!</p>
  <pre><code>$ ffprobe outfile.wav
  Input #0, wav, from 'inp.wav':
    Metadata:
      encoder         : Lavf56.25.101
    Duration: 00:04:00.47, bitrate: 1411 kb/s
      Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 2 channels, s16, 1411 kb/s
  </code></pre>
  <p>You see? encoder metadata exists!</p>
  <p>And in the <code>wav</code> header after &quot;subchunk1_id&quot; with &quot;fmt &quot; value I expect in &quot;subchunk2_id&quot; is the &quot;data&quot; value (clear expected example):</p>
  <pre><code>$ strings outfile.wav | more
  RIFFFB
  WAVEfmt
  data
  </code></pre>
  <p>But it is not (LIST, INFOISFT, etc):</p>
  <pre><code>$ strings outfile.wav | more
  RIFFFB
  WAVEfmt 
  LIST
  INFOISFT
  Lavf56.25.101
  data
  </code></pre>
  <p>Well.. How to really remove all metadata from the output file?</p>