SYSTEM AND METHOD FOR GENERATING VIDEO IN A COMPUTSYSTEM AND METHOD FOR GENERATING VIDEO IN A COMPUTER SYSTEM ER SYSTEM

摘要

A system and method for generating NTSC and PAL formatted composite video signals in a computer. Digital pixel data may be processed by software to form component video pixel data, which may include luminance and chrominance components. A chrominance look-up table is provided in a display memory and is used for modulation of the chrominance components in accordance with NTSC and/or PAL formats. The modulated components are then combined to form digital composite video pixel data which may be stored in a frame buffer in the display memory. Alternatively, a pixel clock frequency equal to an integer multiple of the carrier frequency may be used and modulation in accordance with the NTSC and PAL formats may be accomplished by inverting, setting to zero or leaving unmodified the chrominance components. The architecture of this system greatly reduces hardware complexity and bandwidth requirements. In addition, the process may be controlled by a media stream controller which is also adapted for audio and graphics processing. This allows the display memory and various other components to be shared by multiple media subsystems.