Error resilient transcoding for video over wireless channels
US6339450B1 · kind B1 · utility
Assignees
Inventors
Key dates
| Filing date | Sep 21, 1999 |
| Grant date | Jan 15, 2002 |
| Priority date | — |
| Expiry date | Sep 21, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/89
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and system for maintaining the quality of video transported over wireless channels uses a transcoder to modify and maintain the optical resilience of an encoded bitstream. The transcoder increases the spatial resilience by reducing the number of blocks per slice, and increases the temporal resilience by increasing the proportion of I-blocks that are transmitted in each frame. Also, the transcoder maintains the same input bit rate by dropping less significant coefficients as it increases resilience. The transcoder of the present invention maintains the resilience at an optimal level to accommodate the prevailing channel conditions as measured by the BER of the wireless channel. Rate distortion theory is applied to determine the optimal allocation of bit rate among spatial resilience, temporal resilience and source rate, where it is has been found that the optimal allocation of the present invention (which occurs in near-real time) provides nearly the same result as doing an exhaustive search.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.