atrac3p:band_envelope_processing
Band envelope processing
The band envelope is given as a pair of X/Y values to represent a step function. The X values are quantized down to 32 instead 128 possible values. The Y values are exponents for the base 2, the range is -6 to 9 (so 1/64..512). The envelope will be expanded with geometric interpolation (resulting in 3 interpolated samples) on the step. The left half of the IMDCT result will be scaled by the previous envelope multiplied by the first envelope Y value of the right half.
IMDCT overlapping will be performed immediately after envelope processing.
atrac3p/band_envelope_processing.txt · Last modified: 2009/11/14 19:03 by megadiscman