atrac3p:band_imdct
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| atrac3p:band_imdct [2009/11/14 18:53] – created megadiscman | atrac3p:band_imdct [2010/10/27 08:54] (current) – Add explanation for the reversed storage of odd bands megadiscman | ||
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| ===== Band IMDCT ===== | ===== Band IMDCT ===== | ||
| - | The band IMDCT is a standard 128-point (input) IMDCT, yielding 256 output points. The window for the IMDCT can be steep or soft, which can be chosen for the right half of the current block and is reused for the left half of the next block. As with ATRAC3, the coefficients of odd bands are stored in reverse order. | + | The band IMDCT is a standard 128-point (input) IMDCT, yielding 256 output points. The window for the IMDCT can be steep or soft, which can be chosen for the right half of the current block and is reused for the left half of the next block. As with ATRAC3, the coefficients of odd bands are stored in reverse order because of the spectral mirroring of odd-numbered bands by the QMF synthesis filter. Please note that the block overlapping is not performed yet, but after [[band envelope processing]]. |
| ==== Window descriptions ==== | ==== Window descriptions ==== | ||
atrac3p/band_imdct.1258224826.txt.gz · Last modified: 2009/11/14 18:53 by megadiscman