Controlling a noise-shaping feedback loop in a digital audio signal encoder avoiding instability risk of the feedback
US9489961B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 17, 2011 |
| Grant date | Nov 8, 2016 |
| Priority date | — |
| Expiry date | Dec 13, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/62
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus are provided for controlling the shaping of encoding noise during the ADPCM encoding of a digital audio input signal. The noise-shaping is carried out through the use of feedback that comprises filtering noise. The method includes the following steps: obtaining a parameter for indicating a high spectral dynamic range of the signal, the parameter indicating a risk of instability of the feedback; detecting a risk of instability by comparing the indication parameter to at least one predetermined threshold; limiting the feedback in the event that a risk of instability is detected; and gradually reactivating the feedback over a predetermined number of frames subsequent to the current frame for which the feedback is limited. Also provided is an encoder with feedback, including a control module implementing the control method as described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.