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US 6,297,794 B1Granted
Method of switching video sources and computer system employing this method
AssigneeKabushiki Kaisha Toshiba
InventorsTakumi Tsubouchi, Nobutaka Nishigaki, Makoto Sakai, Toru Honma
Life of this patent
Estimating the term…
Abstract
A plurality of video devices, that is, a PC card controller 17, an MPEG2 decoder 18, a P1394 controller 20, and a video capture 31 have each a motion-picture output port connected to a video/audio dedicated bus 4, as well as an interface with a PCI bus 2. Hence, any motion-picture source can be transferred directly to a display controller 14 through the video/audio dedicated bus, without using the PCI bus 2. Various motion-picture sources can therefore be efficiently displayed.
Claims11
A computer system comprising:
- a video port for receiving motion-picture data;
- a display controller capable of displaying the motion-picture data input to the video port;
- a motion-picture dedicated bus for transferring motion-picture data to a video port of the display controller;
- and
- a plurality of video devices for processing different motion-picture sources, respectively, each having an output port which is connected to said motion-picture dedicated bus and from which motion-picture data is output to said motion-picture dedicated bus,
- said motion-picture dedicated bus including a control signal line which is connected in common to said plurality of video devices which is set into an active state by the video device requesting for use of said motion-picture dedicated bus,
- each of said video devices comprising:
- an output buffer for outputting motion-picture data from said output port to said motion-picture dedicated bus;
- means for setting said signal control line in an active state for a predetermined time, in accordance with a motion-picture data transfer instruction issued from said CPU, and for allowing said output buffer to output the motion-picture data, after said predetermined time has elapsed;
- and
- means for monitoring the state of said control signal line and prohibiting said output buffer from outputting motion-picture data while said control signal remains active,
- whereby the video device set into an active state most recently is allowed to use the motion-picture data dedicated bus.
9 more elements
A computer system comprising:
- a video port for receiving motion-picture data;
- a display controller capable of displaying the motion-picture data input to the video port;
- a motion-picture dedicated bus for transferring motion-picture data to the video port of the display controller;
- and
- a plurality of motion-picture sources, each having an output port which is connected to said motion-picture dedicated bus and from which motion-picture data is output to said motion-picture dedicated bus,
- said motion-picture dedicated bus including a control signal line which is connected in common to said plurality of motion-picture sources which is set into an active state by the motion-picture source requesting use of said motion-picture dedicated bus,
- each of said motion-picture sources comprising:
- an output buffer for outputting motion-picture data from said output port to said motion-picture dedicated bus;
- means for setting said signal control line in an active state for a predetermined time, in accordance with a motion-picture data transfer instruction issued from said CPU, and for allowing said output buffer to output the motion-picture data, after said predetermined time has elapsed;
- means for monitoring the state of said control signal line and prohibiting said control signal line from being set into an active state until said control signal line is released from an active state, when said motion-picture data transfer instruction is issued while the control signal remains in an active state;
- and
- means for monitoring the state of said control signal line and prohibiting said output buffer from outputting motion-picture data while said control signal remains in an active state, whereby the motion-picture source to which a picture-image data transfer instruction is most recently issued from said CPU is allowed to use the motion-picture data dedicated bus.
9 more elements
A computer system comprising:
- a video port for receiving motion-picture data;
- a display controller capable of displaying the motion-picture data input to the video port;
- a motion-picture dedicated bus for transferring motion-picture data to the video port of the display controller;
- and
- a plurality of motion-picture sources, each having an output port which is connected to said motion-picture dedicated bus and from which motion-picture data is output to said motion-picture dedicated bus,
- said motion-picture dedicated bus including a control signal line which is connected in common to said plurality of motion-picture sources which is set into an active state by the motion-picture source requesting for use of said motion-picture dedicated bus,
- each of said motion-picture sources comprising:
- an output buffer for outputting motion-picture data from said output port to said motion-picture dedicated bus;
- means for setting said signal control line in an active state for a predetermined time, in accordance with a motion-picture data transfer instruction issued from said CPU, and for allowing said output buffer to output the motion-picture data, after said predetermined time has elapsed;
- and
- means for monitoring the state of said control signal line and prohibiting said output buffer from outputting motion-picture data while the control signal remains in an active state, wherein the time for which said control signal line is set in an active state in accordance with an motion-picture transfer instruction supplied from said CPU is different for each motion-picture source, and the motion-picture source to which the longest time is assigned is allowed to use the motion-picture data dedicated bus before any other motion-picture source.
8 more elements
A computer system comprising:
- a video port for receiving motion-picture data;
- a display controller capable of displaying the motion-picture data input to the video port;
- a motion-picture dedicated bus for transferring motion-picture data to the video port of the display controller;
- a plurality of motion-picture sources, each having an output port which is connected to said motion-picture dedicated bus and from which motion-picture data is output to said motion-picture dedicated bus;
- and
- means for selecting one of the motion-picture sources, from which motion-picture data is to be transferred to the display controller by using said motion-picture dedicated bus, thereby selecting the video device which uses said motion-picture dedicated bus,
- said selecting means comprising:
- means for managing condition in which said motion-picture sources use said motion-picture dedicated bus;
- means for identifying the motion-picture source now using the motion-picture dedicated line, in response to a request for use of said motion-picture dedicated bus, supplied from a driver program controlling the motion-picture source, and for communicating with the driver program controlling the motion-picture source, thereby determining whether the motion-picture source now using the motion-picture dedicated bus is able to release said motion-picture dedicated bus;
- means for issuing a permission for use of said motion-picture dedicated bus to the driver program which has issued the request for said motion-picture dedicated bus, when the motion-picture source is able to release the motion-picture dedicated bus.
7 more elements
A method of switching video sources in a computer system comprising a video port for receiving motion-picture data, a display controller capable of displaying the motion-picture data input to the video port, a motion-picture dedicated bus for transferring motion-picture data to the video port of the display controller, and a plurality of motion-picture sources, each having an output port which is connected to said motion-picture dedicated bus and from which motion-picture data is output to said motion-picture dedicated bus, said method comprising the steps of:
- managing condition in which said motion-picture sources use said motion-picture dedicated bus;
- identifying the motion-picture source now using said motion-picture dedicated bus in response to a request for use of said motion-picture dedicated bus, supplied from a driver program controlling the motion-picture source, and communicating with the driver program to determine whether the motion-picture source using the motion-picture dedicated bus is able to release the motion-picture dedicated bus;
- and
- issuing a permission for use of said motion-picture dedicated bus to the driver program which has issued the request for said motion-picture dedicated bus, when the motion-picture source is able to release the motion-picture dedicated bus.
1 more element
Dependencies are inferred from the claim text.