Temporal compression and decompression for video
US6008847A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 3, 1997 |
| Grant date | Dec 28, 1999 |
| Priority date | — |
| Expiry date | Mar 3, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/91
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A temporal compression and decompression system is disclosed for color video. A video stream with red, green and blue pixel element values is input to a first computer. In the first computer, a new frame of video data is compared to the frame being displayed on a second computer and the similarity between corresponding blocks and sub-blocks is represented with one tolerance result per sub-block. Based on the number of sub-blocks for which tolerance results exceed a preset threshold and a user-specified quality level, an update quality level is selected that determines the quality at which the frame update is transmitted from the first computer to the second computer. Before the frame update is transmitted the updating information is compressed in a two-stage process. In the first stage 5-bit red, blue and green element values in sub-blocks being updated are is converted to 3-bit categories. In the second stage groups of categories are converted to variable-length Huffman words. The Huffman words are then transmitted over a communications channel to the second computer, which decompresses and displays the updated sub-blocks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.