Multiplexed yuv-movie pixel path for driving dual displays

摘要

A graphics controller has a standard RGB graphics pixel path from a graphics memory. A second path from the graphics memory transfers movie- overlay pixels in YUV format. Two pixel muxes are used. Each pixel mux selects either RGB graphics pixels or YUV movie pixels converted to the RGB color space. A first pixel mux loads either the graphics or the movie pixels to a path to the external CRT. A second pixel mux loads either the graphics or the movie pixels to an LCD path leading to a flat- panel LCD display. The pixel muxes can act in unison to display the same image on both the external CRT and the local LCD panel, and the movie pixels may be overlaid as a small window over the graphics data. The pixel muxes can also act separately so that different images are displayed on the external CRT and the local LCD panel. One pixel mux selects the RGB pixels while the other pixel mux selects the converted YUV pixels. The RGB pixels can be displayed on the LCD panel as graphics data such as speaker's notes, while the YUV pixels can be displayed as a full-screen movie window on the external CRT to an audience. Thus a single graphics controller in a portable PC can drive two different images--one for the audience on the external CRT and a second for the speaker on the portable PC's LCD panel display.