message: Small typo-fix
diff: @@ -131,7 +131,7 @@ For properties you can read and change look into the documentation of the @ref c
  We want to check just how imperceptible our video converting operation went, therefore we need a
  system to check frame by frame the similarity or differences. The most common algorithm used for
  this is the PSNR (aka **Peak signal-to-noise ratio**). The simplest definition of this starts out
  -from the *mean squad error*. Let there be two images: I1 and I2; with a two dimensional size i and
  +from the *mean squared error*. Let there be two images: I1 and I2; with a two dimensional size i and
  j, composed of c number of channels.
  \f[MSE = \frac{1}{c*i*j} \sum{(I_1-I_2)^2}\f]
  