零延时卷积算法实现，基于fft变换。Efficient Convolution Without Latency by

William G. Gardner-It is well known that a block FFT implementation of convolution is vastly more efficient than the direct

form FIR filter. Unfortunately, block processing incurs significant input/output latency which is undesirable

for real-time applications. A hybrid method is proposed for doing convolution by combining direct form

and block FFT processing. The result is a zero latency convolver that performs significantly better than

direct form methods.