In mobile audio device applications, there is sometimes the need to include processing that can change the pitch or tempo of the sound. This additional signal processing can produce a power load on the batteries, which could be minimized if the decoder stage was combined with the pitch-time shift operation. The authors propose a modified AAC (advanced audio coding) decoder structure that can also change the pitch and tempo of an audio signal. To take advantage of the combination, the algorithm includes a preprocessing block before the IMDCT (inverse modified discrete cosine transform) block and a postprocessing block after the overlap and add block. Test results show that the algorithm produces quality results while reducing the computational load to 64% of the separate algorithms.
This paper costs $33 for non-members and is free for AES members and E-Library subscribers.