Patent ID: 7369989

Claim:
An MPEG-1 CODEC, comprising: an encoder that includes means for effecting an analysis filter bank, wherein the means for effecting the analysis filter bank includes a unified filter bank; and a decoder that includes means for effecting a synthesis filter bank, wherein the means for effecting the synthesis filter bank includes a functional inverse of the unified filter bank, wherein the unified filter bank includes a plurality of audio signal filters, where each audio signal filter of the plurality of audio signal filters is a cosine modulation of a prototype filter, P 0 (Z), wherein the prototype filter includes a plurality of polyphase components, G k (Z), which substantially satisfy the following: G ~ k ⁡ ( z ) ⁢ G k ⁡ ( z ) + G ~ M + k ⁡ ( z ) ⁢ G M + k ⁡ ( z ) = 1 2 ⁢ M where G k (z), for 0≦k≦M−1, are the polyphase components of the prototype filter; {tilde over (G)} k (z) is a conjugate transpose of G k (z); M is a decimation factor of the prototype filter; and k is an integer, wherein the MPEG-1 CODEC is a MPEG-1 Layer III CODEC wherein: the prototype filter has a temporal resolution, N, of substantially N+1=1632; the decimation factor, M, of the prototype filter is substantially M=576; and the prototype filter has a bandwidth of substantially π/M.