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San Jose, Calif. - A new proposal before the PCMCIA committee would permit transmission of full CCIR 601 video plus audio over the PCMCIA bus, simultaneously with normal bus activity. The idea would permit full-resolution video-capture cards, MPEG-2 decoder cards and similar functions to be plugged into PCMCIA sockets in mobile computers.
Zoom Video, as the proposal is called, would require a new generation of card, socket-controller and graphics-controller silicon. Taking a risky step forward, Chips & Technologies Inc. and Databook Inc. have announced silicon in support of the new bus. But Cirrus Logic, main proponent of the Zoom Video idea, warned last week that the spec might not be ready for implementation.
In supporting the plan, John Chan, product manager at Chips, said, "Zoom Video makes a place for motion video on the notebook computer, without special proprietary interfaces or compromises in image quality. In effect, it converts a standard PCMCIA socket into a real-time video port."
To do this, the Zoom Video proposal defines a new operating mode on the PCMCIA bus under the Rev. 2 specification. In this mode, 21 pins, including address pins A10 through A25, the interrupt acknowledge and speaker pins are temporarily redefined as a 19-bit video channel. Then one card at a time could stream 16-bit pixels-presumably but not necessarily in YUV 4:2:2 format-plus 2 to 3 bits of audio data directly into the socket controller chip. Running at PCMCIA bus speed, the channel would have a 27-Mbyte/second capacity.
From the socket controller, the video would be sent through a special...