Intel D15343-003 manual Overlay Plane

Functional Description

6.4.6.1Cursor Color Formats

Color data can be in an indexed format or a true color format. Indexed data uses the entries in the four-entry cursor palette to convert the two-bit index to a true color format before being passed to the blenders. The index can optionally specify that a cursor pixel be transparent or cause an inversion of the pixel value below it or one of two colors from the cursor palette. Blending of YUV or RGB data is only supported with planes that have data of the same format.

6.4.6.2Popup Plane (Second Cursor)

The popup plane is used for control functions in mobile applications. Only the hardware cursor has a higher Z-order precedence over the hardware icon. In standard modes (non-VGA) either cursor A or cursor B can be used as a Popup Icon. For VGA modes, 32-bpp data format is not supported.

6.4.6.3Popup Color Formats

Source color data for the popup is in an indexed format. Indexed data uses the entries in the four- entry cursor palette to convert the two-bit index to a true color format before being passed to the blenders. Blending of color data is only supported with data of the same format.

6.4.7Overlay Plane

The overlay engine provides a method of merging either video capture data (from an external Video Capture device) or data delivered by the CPU, with the graphics data on the screen.

6.4.7.1Multiple Overlays (Display C)

A single overlay plane and scalar is implemented. This overlay plane can be connected to the primary display, secondary display or in bypass mode. In the default mode, it appears on the primary display. The overlay may be displayed in a multi-monitor scenario for single-pipe simultaneous displays only. Picture-in-Picture feature is supported via software through the arithmetic stretch BLT.

6.4.7.2Source/Destination Color/Chromakeying

Overlay source/destination chromakeying enables blending of the overlay with the underlying graphics background. Destination color-/chromakeying can be used to handle occluded portions of the overlay window on a pixel-by-pixel basis that is actually an underlay. Destination color keying supports a specific color (8-bit or 15-bit) mode as well as 32-bit alpha blending.

Source color/chromakeying is used to handle transparency based on the overlay window on a pixel-by-pixel basis. This is used when "blue screening" an image to overlay the image on a new background later.

6.4.7.3Gamma Correction

To compensate for overlay color intensity loss, the overlay engine supports independent gamma correction. This allows the overlay data to be converted to linear data or corrected for the display device when not blending.

6.4.7.4YUV to RGB Conversion

The format conversion can be bypassed in the case of RGB source data.

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