Adaptive digital audio encoding apparatus and a bit allocation method thereof
US5537510A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 30, 1994 |
| Grant date | Jul 16, 1996 |
| Priority date | — |
| Expiry date | Dec 30, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/665
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A novel apparatus, capable of adaptively encoding an input digital audio signal, comprises a subband filtering device for receiving the input digital audio signal and filtering the received digital audio signal, on a subband-by-subband basis; a first estimator for estimating signal-to-mask ratio data, sound pressure levels and masking thresholds for the respective subbands of the digital audio signal; a second estimator for estimating perceptual entropies for the respective frames of the input digital audio signal based on the estimated signal-to-mask ratio data, sound pressure levels and masking thresholds and for deriving a mean and a standard deviation parameters for a frame group including two or more current and previous frames which corresponds to the estimated perceptual entropies; a bit allocation unit for adaptively determining bits for each of the subbands based on the estimated signal-to-mask ratio data, perceptual entropies, and mean and standard deviation parameters and for generating bit allocation information corresponding to the determined bits for each of the subbands; a quantizer for quantizing each of the filtered subbands of the digital audio signal in response …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.