The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 29, 2000
Filed:
Feb. 03, 1998
Brittain S McKinley, Melrose, MA (US);
VideoServer, Inc., Burlington, MA (US);
Abstract
A de-framer (72) in a communications gateway (22) translates videoconferencing information from a circuit-switched format to a packet-switched format. A demultiplexor (78) extracts a bitstream containing video information that includes error-correction-code fields disposed at predetermined locations with respect to synchronization bits spaced by a synchronization interval and forming a predetermined synchronization sequence. A frame checker (88) for checking the error-correction code finds codeword boundaries by comparing the predetermined synchronization sequence with sequences of synchronization-interval-spaced video-bitstream bits until it finds a match. To do so, the frame checker (88) takes a group of video-bitstream words offset from each other by the synchronization interval. It compares each word in the group with a respective synchronization word consisting of a word-width replication of a respective synchronization bit. Enough words resulting from the comparisons are ORed together that the result will be all ones unless each video-bitstream word contains a respective synchronization bit in a corresponding bit position. If the result does contain a zero, then it can be inferred that the video bitstream contains synchronization bits in corresponding bit positions.