Predictive coding and decoding with error drift reduction
US5291284A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 23, 1991 |
| Grant date | Mar 1, 1994 |
| Priority date | — |
| Expiry date | Jul 23, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/61
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A predictive coder, e.g., a hybrid DCT interframe predictive video decoder, reduces the tendency of long-term bias error in the decoded difference signal to accumulate in a predictor (7) by periodically alternating the polarity of the bias error relative to the contents of the predictor. Inverse discrete cosine transform (IDCT) stage (6) in a receiver is bracketed by switchable invertors (9a,9b) which, when operating, invert the signal into IDCT stage (6) and then reinvert the signal, plus error, out of IDCT stage (6), thereby inverting the error relative to the difference signal. Control means (10), e.g., a pseudo-random number generator, switches the invertors (9a,9b) in and out periodically such that, over several frames, each block spends an equal amount of time in "normal" and "inverted" modes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.