Low bit-rate high-resolution spectral envelope coding for audio encoder and decoder
US5581653A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 31, 1993 |
| Grant date | Dec 3, 1996 |
| Priority date | — |
| Expiry date | Aug 31, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/667
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A split-band encoder prepares an estimate of an input signal spectral envelope by splitting the input signal into frequency subband signals, generates a scaled representation of the subband signals comprising scaling factors and scaled values, generates a differential coded representation of the scaling factors, and assembles the differential coded representation and scaled values into an encoded signal. The scale factors represent a spectral envelope of the input signal and spectral leakage between filterbank subbands limits the change in value between adjacent scaling factors. This limitation in change can be exploited to reduce the informational requirements of the differential coded representation. Adaptive selection between high- and low-resolution spectral envelopes and adaptive scaling factor reuse are described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.