Fast codebook search method for MPEG audio encoding
US6542863B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 14, 2000 |
| Grant date | Apr 1, 2003 |
| Priority date | — |
| Expiry date | Jan 20, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L2019/0013
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A fast codebook search method for finding an optimal Huffman codebook from a group of Huffman codebooks, wherein the method is especially suited for MPEG-compliant audio encoding. In order to select an optimal codebook from among candidate codebooks for a given sub-region, a bit difference table is created, which for any given data pair contains a bit difference value. The bit difference value is the difference between the number of bits needed for a given data pair (or quadruple) in a first candidate codebook and a second candidate codebook [N bits−M bits]. By summing all such bit difference values for the data samples in a given sub-region, a quick determination can be made as to which codebook would encode the sub-region using the fewest bits (based on the size and/or sign of the sum(s)). For sub-regions having three candidate codebooks, two bit difference sums are calculated. For an implementation of the MPEG-1 Layer III Audio Encoding standard, only 20 bit difference tables are required in order to cover every possible combination of codebook candidates.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.