Fast system and method for computing modulated lapped transforms

A fast computation system stored on computer readable memory of a computer system for processing an input signal, the fast computation system comprising:

• a first multiplication module that multiplies at least two samples of the input signal by a first pre-computed set of ratios of window coefficients to produce a first output;
• a combination module that combines a portion of the samples of the input signal with the first output to produce a second output;
• a second multiplication module that multiplies at least a portion of the second output by a second pre-computed set of ratios of window coefficients to produce a third output;
• and
• a reordering module reordering for the third output for computing a modulated transform of the input signal.

A computer-implemented method for computing an inverse biorthogonal modulated lapped transform of a received first sample and a second sample representing decoded and inverse transformed data of an original input signal, the method comprising;

• delaying the second sample and allowing the first sample to be undelayed;
• producing respective first and second multiplied outputs using a first pre-computed set of ratios of window coefficients;
• producing respective third and fourth multiplied outputs using a second pre-computed set of ratios of window coefficients;
• and
• reordering and combining the third and fourth multiplied outputs to produce respective first and second combined outputs corresponding to a reconstructed version of the original input signal.

A computer-implemented method for processing an input signal having a plurality of sample blocks, comprising:

• applying a window operator having a first set of weights to the input signal to produce a windowed signal;
• performing a discrete cosine transform operation on the windowed signal to produce a transform signal;
• and
• applying a special matrix operator to the transform signal to produce an encoded output signal corresponding to the input signal.