| 摘要 |
An encoder may include a core MDCT filterbank that can be used to implement an advanced audio coding (AAC) algorithm, an AAC-enhanced low delay (ELD) algorithm or both algorithms. For the AAC algorithm, a sequence of input samples is sent directly to the MDCT filterbank to obtain a sequence of output samples. For the AAC-ELD algorithm, the signs of input samples of the sequence of input samples are inverted, the MDCT analysis filterbank is applied to the sign-inverted sequence of input samples to obtain a sequence of output samples, the order of the sequence of output samples is reversed, and the signs of alternating output samples of the sequence of output samples are inverted. Similarly, a decoder may include a core IMDCT synthesis filterbank that can be used to implement AAC-ELD or both AAC and AAC-ELD algorithms. The steps for the decoder are merely the reverse of the encoder.
|
