Method and apparatus for improved significance flag coding using simple local predictor
AssigneeInterDigital VC Holdings, Inc.
InventorsSebastien LASSERRE, Pierre ANDRIVON, Philippe BORDES
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Abstract
Significance flags in advanced video compression systems are coded using contexts adaptive to the last N significance flags coded taken in a scanning order. One embodiment uses the last N significance flags in scanning order as a predictor to determine which of a plurality of sets of significance flag contexts to use for coding subsequent significance flags. A second embodiment uses the last N significance flags in scanning order as a predictor in order to modulate the probability value associated with significance flag contexts that are used to code significance flags for future coding.
Claims13
A method for video coding, comprising:
- modifying a significance flag context based on a plurality of the last N significance flags corresponding to a scanning order of a portion of an image, modified by selecting a set of significance flag contexts to use for coding subsequent significance flags, the set comprising a predictor for updating a probability based on past significance flags according to a scanning order;
- and
- coding a subsequent significance flag using said modified significance flag context.
A method for video decoding, comprising:
- modifying a significance flag context based on a plurality of the last N significance flags corresponding to a scanning order of a portion of an image;
- and
- decoding a subsequent significance flag using said modified significance flag context, wherein the significance flag context is modified by selecting a set of significance flag contexts to use for coding subsequent significance flags, the set comprising a predictor for updating a probability based on past significance flags according to a scanning order.
An apparatus for video coding, comprising:
- a processor, configured to modifying a significance flag context based on a plurality of the last N significance flags corresponding to a scanning order of a portion of an image;
- and
- an encoder that uses the modified significance flag context in encoding video for a portion of an image, wherein the significance flag context is modified by selecting a set of significance flag contexts to use for coding subsequent significance flags, the set comprising a predictor for updating a probability based on past significance flags according to a scanning order.
An apparatus for video decoding, comprising:
- a processor, configured to modifying a significance flag context based on a plurality of the last N significance flags corresponding to a scanning order of a portion of an image;
- and
- a decoder that uses the modified significance flag context in decoding video for a portion of an image, wherein the significance flag context is modified by selecting a set of significance flag contexts to use for coding subsequent significance flags, the set comprising a predictor for updating a probability based on past significance flags according to a scanning order.
Dependencies are inferred from the claim text.