Adds two new apodization functions that seem to perform better than
the apodization functions currently in the codebase and fixes three
existing windows as well.
Its important to note that this patch only affects the encoder stage
that evaluates various possible predictors. Audio encoded with these
new windows will still decode with existing legacy decoders.
= Theory =
These functions are used to window the audio data at the predictor
stage. These news functions enable the use of only part of the signal
to generate a predictor. This helps because short transients can
introduce noise into the predictor. The predictor becomes very good
at prediciting one part of the signal, instead of mediocre for the
whole block.
Signed-off-by: Erik de Castro Lopo <erikd@mega-nerd.com>
