Arithmetic coding encoder and decoder system
CA 1291821 C · Owner: Langdon, Glen G. Jr. · Inventors: Rissanen, Jorma J.; Mitchell, Joan L.; Langdon, Glen G. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Apparatus and method for compressing and de-compressing binary decision data by arithmetic coding and decoding wherein the estimated probability Qe of the less probable of the two decision events, or outcomes, adapts as decisions are successively encoded. To facilitate coding computations an, augend value A for the current number line interval is held to approximate one by renormalizing A whenever it becomes less than a prescribed minimum AMIN. When A is renormalized the value of Qe is up-dated. The renormalization of A and up-dating of Qe are preferably based on a single-bit test. Also each Qe value is preferably specified as a 12-bit value having the least significant bit set to 1 and …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted November 5, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 5, 2008.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.