Method and apparatus to encode/decode low bit-rate audio signal by approximiating high frequency envelope with strongly correlated low frequency codevectors
US8301439B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 2006 |
| Grant date | Oct 30, 2012 |
| Priority date | — |
| Expiry date | Jan 6, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/06
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of encoding a low bit-rate audio signal includes quantizing and encoding a plurality of low frequency sub-bands of an audio signal in a frequency domain, generating a codebook of codevectors using sub-bands of the audio signal spectrum, detecting an envelope of another frequency sub-band of the audio signal and quantizing and losslessly-encoding the detected envelope, selecting a codevector most similar to the higher frequency sub-band spectrum from the generated codebook's codevectors and determining its codebook codevector index, and generating a bit stream. Decoding the low bit-rate audio signal includes restoring and dividing a bit stream into a plurality of first frequency sub-bands and at least one second frequency sub-band and inversely quantizing the first frequency sub-bands in the bit stream, restoring codebook codevector index information and envelope information for the second frequency sub-band, generating a codebook of codevectors using the inversely quantized first frequency sub-bands, and restoring the second frequency sub-band using the restored codevector index information and the envelope information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.