Modified Discrete Cosine Transform (MDCT) filter bank, or often called as Time Domain Aliasing Cancellation (TDAC) filter bank, is widely used in audio coding systems. The last step of the conventional MDCT filter bank is the dual overlap add procedure to restore uncompressed original signal. The last step can be generalized using the multiple overlap add procedure, in which the input and output block size can be reduced as the number of overlapped windows increases. The MDCT system with multiple overlap add can reveal scalability features in proportion to the number of overlapped windows when it is used along with the fixed bit adaptive quantization capable of maintaining nearly the same SNR irrespective of the input level. It has been shown that the proposed structure is scalable in block unit with the same data rate as the conventional system and that it shows slight SNR improvement over conventional one.
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