Method for decompressing linear PCM and AC3 encoded audio gain value
US6112170A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1998 |
| Grant date | Aug 29, 2000 |
| Priority date | — |
| Expiry date | Jun 26, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/083
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An audio decoder which includes a coefficient memory and an arithmetic logic unit (ALU) can implement an efficient method for calculating a gain value specified by a range control field. In one embodiment, the audio decoder comprises coefficient memory, an ALU, frame control logic, and ALU control logic. The frame control logic extracts a range control field value from an audio packet header and provides it to the ALU control logic. The ALU control logic takes the binary representation of the range control field value and uses it to provide a sequence of addresses to the coefficient memory. In response to the sequence of addresses, the coefficient memory provides a sequence of pre-calculated factors to the ALU. The ALU control logic further directs the ALU to determine the product of the pre-calculated factors in the sequence. As a final step in finding the gain value, the ALU control logic may provide a shift instruction to the ALU. In one specific implementation, there is a maximum of three pre-calculated factors and one shift instruction required for one calculation of the gain value, and a required storage of only seven non-unity pre-calculated factors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.