Encoding/decoding moving images with forward and backward keyframes for forward and reverse display
US5267334A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 1993 |
| Grant date | Nov 30, 1993 |
| Priority date | — |
| Expiry date | Jan 21, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/152
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of removing frame redundancy in a computer system for a sequence of moving images. The method comprises detecting a first scene change in the sequence of moving images and generating a first keyframe containing complete scene information for a first image. The first keyframe is known, in a preferred embodiment, as a "forward-facing" keyframe or intra frame, and it is normally present in CCITT compressed video data. The process then comprises generating at least one intermediate compressed frame, the at least one intermediate compressed frame containing difference information from the first image for at least one image following the first image in time in the sequence of moving images. In a preferred embodiment, this at least one frame is known as an inter frame. Finally, detecting a second scene change in the sequence of moving images and generating a second keyframe containing complete scene information for an image displayed at the time just prior to the second scene change. This is known, in the preferred embodiment, as a "backward-facing" keyframe. The first keyframe and the at least one intermediate compressed frame are linked for forward play, and the second keyframe…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.