I am Mynampati Kuldeep Kumar. I am working on MPEG-2 AAC Low Delay Filter Bank.
In this it has an algorithmic delay of 20 ms. The reason is as follows
A forward and Inverse MDCT with N Frequency bands introduces a delay of 2*N-1
samples. By decomposing the MDCT into Windowing /TDAC and DCT (Type-4) it can be
observed that DCT-4 generates N-1 Sample delay and Windowing/TDAC generates
additional N samples delay.
To reduce the delay, dependency in the analysis filter bank only in Forward
direction that is previous block does not depend on current block then there is
chance to have low delay .So, it requires a New Windowing
method or modification of existing Sine window that should satisfy Time Domain
Aliasing and Perfect Reconstruction and Samples depend only on Current block
Any suggestion or web sites/literature regarding this is highly appreciated and
would be a great help.
Mynampati Kuldeep Kumar