Using gain-adaptive quantization and non-uniform symbol lengths for improved audio coding
US6246345A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 8, 1999 |
| Grant date | Jun 12, 2001 |
| Priority date | — |
| Expiry date | Jul 8, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/0208
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Techniques like Huffman coding can be used to represent digital audio signal components more efficiently using non-uniform length symbols than can be represented by other coding techniques using uniform length symbols Unfortunately, the coding efficiency that can be achieved by Huffman coding depends on the probability density function of the information to be coded and the Huffman coding process itself requires considerable processing and memory resources. A coding process that uses gain-adaptive quantization according to the present invention can realize the advantage of using non-uniform length symbols while overcoming the shortcomings of Huffman coding. In gain-adaptive quantization, the magnitudes of signal components to be encoded are compared to one or more thresholds and placed into classes according to the results of the comparison. The magnitudes of the components placed into one of the classes are modified according to a gain factor that is related to the threshold used to classify the components. Preferably, the gain factor may be expressed as a function of only the threshold value. Gain-adaptive quantization may be used to encode frequency subband signals in split-band…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.