Perceptual coding of audio signals
US5341457A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 1993 |
| Grant date | Aug 23, 1994 |
| Priority date | — |
| Expiry date | Aug 20, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/0212
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A technique for the masking of quantizing noise in the coding of audio signals is adapted to include geometric interpolation between the thresholds for a tone masking noise and for noise masking a tone, in order to reduce use of bit-rate capability where it is not necessary for transparent or high quality. The technique is usable with the types of channel coding known as "noiseless" or Huffman coding and with variable radix packing. The stereophonic embodiment eliminates redundancies in the sum and difference signals, so that the stereo coding uses significantly less than twice the bit rate of the comparable monaural signal. The technique can be used both in transmission of signals and in recording for reproduction, particularly recording and reproduction of music. Compatibility with the ISDN transmission rates known as 1 B, 2 B and 3 B rates has been achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.