An application that is widely used is in the last stage of the calculation of the MEL frequency cepstral coefficients (MFCC). After computation of the log of the MEL band energies, which are represented by the input data vector $ {\bf x}$, the DCT is applied, and normally only about half of the DCT coeffients are retained. This operation (truncated DCT) can be represented by a single matrix multiplication $ {\bf z}={\bf A}{\bf x}.$. For MaxEnt PDF projection, we also require the total energy $ t_2({\bf x})={\bf x}^\prime {\bf x}.$ For more details, see Chapter 10

Baggenstoss 2017-05-19