What is Zoomed Video?
Zoomed Video is a protocol which allows a device to send graphics and sound data directly to the VGA and audio sub-system controllers. For the PC Card Controller, some PC Cards support Zoomed Video, primarily MPEG I decoder PC Cards. For an MPEG Decoder PC Card, the undecoded MPEG stream is read from a CD-ROM which is on the PCI bus. This data is transferred through the PC Card Controller to the PC Card. Twenty-three lines on the PC Card interface are tri-stated during ZV Playback and are routed on the system board to the VGA controller and audio sub-system. The PC Card decodes the data from the PC Card Controller and then sends the decoded video/audio stream directly to the Video/Audio sub-systems. The benefit of ZV is the ability to reduce bandwidth traffic on the PCI bus by sending the audio/graphics data directly to the subsystems, thereby bypassing the PCI bus. ZV can also be supported from other sources, beyond the PC Card. In this case, the platform will typically need to provid
