title: Explanation of audio stat using sox
body: <p>I have a bunch of audio files and need to split each files based on silence and using <a href="http://sox.sourceforge.net/sox.html" rel="noreferrer">SOX</a>. However, I realize that some files have very noisy background and some don't thus I can't use a single set of parameter to iterate over all files doing the split. I try to figure out how to separate them by noisy background. Here is what I got from <code>sox input1.flac -n stat</code> and <code>sox input2.flac -n stat</code></p>
  <pre><code>Samples read:          18207744
  Length (seconds):    568.992000
  Scaled by:         2147483647.0
  Maximum amplitude:     0.999969
  Minimum amplitude:    -1.000000
  Midline amplitude:    -0.000015
  Mean    norm:          0.031888
  Mean    amplitude:    -0.000361
  RMS     amplitude:     0.053763
  Maximum delta:         0.858917
  Minimum delta:         0.000000
  Mean    delta:         0.018609
  RMS     delta:         0.039249
  Rough   frequency:         1859
  Volume adjustment:        1.000
  </code></pre>
  <p>and</p>
  <pre><code>Samples read:         198976896
  Length (seconds):   6218.028000
  Scaled by:         2147483647.0
  Maximum amplitude:     0.999969
  Minimum amplitude:    -1.000000
  Midline amplitude:    -0.000015
  Mean    norm:          0.156168
  Mean    amplitude:    -0.000010
  RMS     amplitude:     0.211787
  Maximum delta:         1.999969
  Minimum delta:         0.000000
  Mean    delta:         0.091605
  RMS     delta:         0.123462
  Rough   frequency:         1484
  Volume adjustment:        1.000
  </code></pre>
  <p>The former does not contain noisy background and the latter does. I suspect I can use the <code>Sample Mean</code> of <code>Max delta</code> because of the big gap.
  Can anyone explain for me the meaning of those stats, or at least show me where I can get it myself (I tried looking up in official documentation but they don't explain). Many thanks.</p>