Apparatus and method for blending graphics and video surfaces
AssigneeBroadcom Corporation
InventorsAlexander G. MacInnis, Chengfuh Jeffrey Tang, Xiaodong Xie, James T. Patterson, Greg A. Kranawetter
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Abstract
A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, and graphics input. The chip blends graphics and video information by various graphics windows using alpha values for the windows, alpha values per pixel, or both. The chip calculates a composite alpha value based on the window's alpha values and the alpha values per pixel. Blended graphics and video may then be composited using the composite alpha value.
Claims18
A method of blending a plurality of image layers comprising:
- organizing the plurality of image layers into upper image layers and at least one lower image layer;
- blending the upper image layers into a blended upper image layer;
- combining a plurality of alpha values associated with the upper image layers into a plurality of composite alpha values;
- and
- compositing the blended upper image layer and the at least one lower image layer using the plurality of composite alpha values.
A display system for compositing a plurality of image layers comprising upper image layers and at least one lower image layer, comprising:
- a display engine for blending the upper image layers into a blended upper image layer and for combining a plurality of alpha values associated with the upper image layers into a plurality of composite alpha values;
- and
- a compositor for compositing the blended upper image layer and the at least one lower image layer using the plurality of composite alpha values.
Dependencies are inferred from the claim text.