Low-complexity encoding/decoding of quantized MDCT spectrum in scalable speech and audio codecs
US8527265B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 21, 2008 |
| Grant date | Sep 3, 2013 |
| Priority date | — |
| Expiry date | Jul 27, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/038
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A scalable speech and audio codec is provided that implements combinatorial spectrum encoding. A residual signal is obtained from a Code Excited Linear Prediction (CELP)-based encoding layer, where the residual signal is a difference between an original audio signal and a reconstructed version of the original audio signal. The residual signal is transformed at a Discrete Cosine Transform (DCT)-type transform layer to obtain a corresponding transform spectrum having a plurality of spectral lines. The transform spectrum spectral lines are transformed using a combinatorial position coding technique. The combinatorial position coding technique includes generating a lexicographical index for a selected subset of spectral lines, where each lexicographic index represents one of a plurality of possible binary strings representing the positions of the selected subset of spectral lines. The lexicographical index represents non-zero spectral lines in a binary string in fewer bits than the length of the binary string.
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