# US 5,706,451 A · Displaying a subsampled video image on a computer display > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,706,451 A - Document ID: US5706451A - Status: Granted - Kind: A - Application number: 08/563,263 - Filed: 1995-11-27 - Granted: 1998-01-06 - Earliest claimed: 1993-04-16 - Assignees: Media 100 Inc. - Inventors: Timothy R. Lightbody; Daniel F. Cutter; Brian M. Nowokunski - Web page: https://patentgrep.com/patent/US5706451A ## CPC - G11B 27/34: Indicating arrangements {(indicating means incorporated in magazine or cassette G11B23/046 and G11B23/0875; indicating measured values in general G01D)} - G06F 3/14: Digital output to display device {; Cooperation and interconnection of the display device with other functional units} - G09G 5/02: characterised by the way in which colour is displayed {(details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607)} - G11B 27/031: Electronic editing of digitised analogue information signals, e.g. audio or video signals - H04N 5/765: Interface circuits between an apparatus for recording and another apparatus - G09G 2310/0229: De-interlacing - G09G 2340/02: Handling of images in compressed format, e.g. JPEG, MPEG - G09G 2340/125: wherein one of the images is motion video - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Apparatus for displaying a reduced-size image in a window of the display of a host computer, the reduced-size image based upon subsampled digital image data. The apparatus includes a host computer and a peripheral controller. The peripheral controller includes a subsampler that receives digital source image data and outputs subsampled image data, and window display circuit. The window display circuit receives a directive from the host computer indicating a window location on the host's display, and the subsampled image data. The window display circuit autonomously (independently of the host CPU) writes the subsampled data through the host's system bus into the display memory at addresses corresponding to the specified window. The apparatus allows video to be displayed on the display screen while avoiding intensive involvement or supervision by the host CPU during display of the video image data. ## Claims ### Claim 1 Apparatus for displaying a reduced-size image in a window of a display of a host computer, the image being based upon subsampled digital image data, the host computer including a central processing unit (CPU), a display, a display memory connected to said display, and a bus connected to said central processing unit and said display memory, said apparatus comprising: a peripheral controller including a subsampler that receives digital source image data and outputs subsampled image data, and a window display circuit that autonomously writes said subsampled data through said bus into said display memory at addresses corresponding to said window, said writing being carried out independently of said host CPU. ### Claim 2 (depends on 1) The apparatus of claim 1 wherein said subsampler is programmable to extract a subsampled subset of said digital image data such that the subsampled image data create an image in said window on said display having a desired image size. ### Claim 3 (depends on 2) The apparatus of claim 2 wherein said programming of the image size of said window is under the direction of said host computer. ### Claim 4 (depends on 1) The apparatus of claim 1 wherein said digital source image data are in an interlaced form, and said window display circuit de-interlaces scan lines of fields of interlaced image data. ### Claim 5 (depends on 4) The apparatus of claim 4 wherein said display memory comprises memory cells at a plurality of addresses, and said window display circuit comprises an address generator for generating addresses in said display memory, said generated display memory addresses being partitioned into sequential groups corresponding to said scan lines, and ordered to effect said de-interlacing of said interlaced scan lines. ### Claim 6 (depends on 4) The apparatus of claim 4 wherein said subsampler outputs said subsampled image data in an interlaced order, and the apparatus further comprises a queuing store in which said interlaced subsampled image data are stored, and wherein said window display circuit unloads said interlaced subsampled image data from said queuing store and stores successive scan lines of said subsampled image data into alternate scan lines of said display memory. ### Claim 7 (depends on 1) The apparatus of claim 1 further comprising a FIFO for storing said subsampled data before said subsampled data are written to said display memory. ### Claim 8 (depends on 1) The apparatus of claim 1 wherein said window display circuit comprises control means to establish a screen location and size of said window and memory locations in said display memory corresponding to said screen location, and means to transfer said subsampled data to said display memory without requiring intervention of said host CPU. ### Claim 9 (depends on 1) The apparatus of claim 1 further comprising window specification means that receives from an application program running on said host computer a screen location and image size of said window, and controls said window display circuit to write said subsampled data into said display memory at memory locations corresponding to the screen location of said window so that said image data can thereafter be transferred to said host display memory without requiring the involvement or intervention of the host CPU. ### Claim 10 (depends on 9) The apparatus of claim 9 wherein said window specification means comprises means for re-sizing and repositioning said window at another screen location as specified by a user of said host computer, and for controlling said window display circuit to write said subsampled data into said display memory at memory locations corresponding to said re-sized or re-positioned screen location. ### Claim 11 (depends on 1) The apparatus of claim 1 wherein said subsampled data are written into said display memory to provide an image on said display that changes as a function of time. ### Claim 12 (depends on 1) The apparatus of claim 1 wherein said subsampled image data are displayed on said display with intervention required from the host processor less often than once per frame. ### Claim 13 (depends on 1) The apparatus of claim 1 wherein said display memory has a predetermined protocol for representing the color and brightness value of a pixel on the display, and said peripheral controller further comprises a color space converter for converting said digital image data to image data in said predetermined protocol required by the display. ### Claim 14 (depends on 13) The apparatus of claim 13 wherein said converter converts said digital image data to said predetermined protocol before said subsampler subsamples said image data. ### Claim 15 (depends on 1) The apparatus of claim 1 wherein said host computer is a personal computer, and said peripheral controller is configured as one or more boards to plug into an expansion slot of a personal computer. ### Claim 16 (depends on 1) The apparatus of claim 1 wherein said bus is a private bus to which said CPU and said display memory of said host computer are connected, and said peripheral controller is connected to said display memory through both a system bus and said private bus. ### Claim 17 (depends on 1) The apparatus of claim 1 wherein said bus is a system bus, and said CPU, display memory, and peripheral controller are connected directly to said system bus. ### Claim 18 (depends on 1) The apparatus of claim 1 wherein said window display circuit blocks said subsampled image data into blocks for efficient transfer across said bus into said display memory. ### Claim 19 Apparatus for displaying a reduced-size image in a window of a display of a host computer, the image being based upon subsampled digital image data, the host computer including a central processing unit (CPU), a display, a display memory connected to said display, and a bus connected to said central processing unit and said display memory, said apparatus comprising: a peripheral controller including a subsampler that receives digital source image data and outputs subsampled image data, and a window display circuit that autonomously writes said subsampled data through said bus into said display memory at addresses corresponding to said window, said writing being carried out independently of said host CPU, wherein said peripheral controller further comprises other data transfer paths, and a priority scheduler to temporarily suspend said window display circuit in order to allow the timely completion of transfer of data of priority higher than said subsampled data. ### Claim 20 (depends on 19) The apparatus of claim 19 wherein said other data transfer paths comprise FIFOs for temporarily storing data on those paths, each said FIFO having monitoring means for determining the amount of data in said FIFO, and said priority scheduler monitors said monitoring means to suspend said window display circuit. ### Claim 21 (depends on 19) The apparatus of claim 19 further comprising means for restarting said window display circuit when said higher-priority transfer is complete, said restarting being effected without the supervision of said host CPU. ### Claim 22 (depends on 9) The apparatus of claim 9 wherein said other data transfer paths comprise a compression coder or a decompression decoder. ### Claim 23 Apparatus for displaying digital image data on the display of a host computer, the display having a memory-mapped display memory with a predetermined protocol for representing the color and brightness value of a pixel on the display, the apparatus comprising: a peripheral processor that autonomously takes as input the digital image data and stores it into a target display area of the host's display by writing into the display memory; wherein as part of displaying, the peripheral processor decodes the digital image data from one encoding to the predetermined protocol required by the display; such that active real-time video is displayed on the host's display with intervention required from the host processor less often than once per frame. ### Claim 24 (depends on 23) The apparatus of claim 23 wherein said decoding comprises color space conversion. ### Claim 25 (depends on 23) The apparatus of claim 23 wherein said decoding comprises de-interlacing. ### Claim 26 (depends on 23) The apparatus of claim 23 further comprising a FIFO for storing said decoded image data before said decoded image data are stored into said target display area. ### Claim 27 A method for displaying a reduced-size video image in a window of a display of a host computer, the reduced-size image displaying subsampled digital image data, the host computer including a central processing unit (CPU), a display, a display memory connected to said display, and a bus connected to said central processing unit and said display memory, the method comprising the steps of: receiving said image data a peripheral controller, and autonomously subsampling said image data, and writing said subsampled data through said bus into said display memory at addresses corresponding to said window, said receiving, subsampling, and writing being carried out without substantial intervention by said host CPU.