Compressed audio signal processing
US5864816A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 27, 1997 |
| Grant date | Jan 26, 1999 |
| Priority date | — |
| Expiry date | Mar 27, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/667
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Techniques for applying attenuation to audio signal frames in MPEG and similar compression systems are described, together with a method for mixing such signals without decompression. Each entry in a data frame (F) has an associated scale-factor index (SF), identifying a respective entry in a sequentially arranged and spaced table of scale-factor values. The attenuation technique (20), which suitably precedes mixing for at least one channel involves simple addition to scale factor index values to refer to a different scale-factor value. Respective sub-band data groups from each channel are compared in terms of their respective scale factors and following scaling the data for the two groups is added together. The scale-factor table spacing, which suitable corresponds to a 1 dB attenuation, is used for quick scaling of the results of the addition if overflow is determined to have occurred.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.