Method and encoder for bit-rate saving encoding of audio signals
US6873950B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 2000 |
| Grant date | Mar 29, 2005 |
| Priority date | — |
| Expiry date | Nov 17, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L25/27
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
MPEG 1 Audio data compression is based on subband coding. A quantization is performed using a psychoacoustic model which is adapted to the masking behavior of the human hearing. Each subband signal is quantized in such a way that the quantization noise introduced by the coding will not exceed the masking curve for that subband. In ISO/IEC 11172-3 two independent psychoacoustic models are defined. The output from these psychoacoustic models is a set of Signal-to-Masking Ratios, SMRn, for every subband n. In order to calculate the SMRn for the psychoacoustic model 2 according to the invention a Fast Fourier Transformation is performed with a length of L=1152 samples by calculating k subtransformations over 2N samples with k*2N=L and fitting together the results of the k subtransformations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.