Accelerated pixel data movement

A method of panning a video display of a displayed portion of a larger image around the larger image which larger image is stored electronically in an image memory and which displayed portion is displayed on a video monitor, the method comprising:

• a) designating starting image memory row and column addresses within the larger image;
• b) in coordination with a horizontal raster control signal for controlling horizontal readout of a row of video data from a video memory to the video monitor, transferring during the horizontal read out image values along a row portion commencing at the starting row and column addresses from the image memory to memory elements of a starting memory element row of the video memory which video memory has a plurality of rows of video memory elements, the number of video memory rows corresponding to a number of raster lines in the video display and each video memory row having a number of memory elements corresponding to a number of pixels along each raster line of the video display and increasing the starting image memory row address;
• c) in coordination with a subsequent horizontal raster control signal, transferring during a corresponding horizontal readout image values from the image memory along an image memory row portion commencing with the indexed image memory row address and the starting column address to video memory elements of a next row of the video memory and indexing the indexed image memory row address and concurrently transferring image values from video memory elements of a preceding row of the video memory to the video monitor to form one line of the video display;
• d) repeating step (c) a plurality of times;
• e) after image values have been transferred into video memory elements of a last row of the video memory, indexing the image memory starting addresses and repeating steps (b)-(d) such that the video display pans across the image.

A method of handling video data movement through a video memory that has a plurality of memory planes, each memory plane being defined by a matrix of memory elements identified by row and column coordinates, the method comprising:

• conveying a stream of bits of packed data in which a preselected plurality of bits corresponds to each pixel of a video monitor;
• channelling bits of like significance corresponding to each pixel to corresponding row and column coordinates in a corresponding ones of the memory planes;
• during a vertical retrace of the video monitor, storing the bits channeled to the memory planes in at least an earliest displayed row of the memory plane;
• concurrently (i) horizontally reading out the bits from an earlier displayed row of the memory planes to the video monitor and (ii) storing the bits channelled to a later displayed row of the memory planes such that the bits are read from the memory planes to the video monitor for display a fraction of a frame after being read into the memory planes;
• repeating the concurrent reading and storing until the bits channelled to the memory planes are stored in a last displayed row;
• repeating the reading until the bits from the last displayed row are read to the video monitor.

A video panning system comprising:

• a video monitor having raster movement that is controlled by horizontal and vertical synchronization pulses to generate a video display having a grid of pixels defined by a selected number of pixel rows and a selected number of pixel columns;
• a video random access memory means including a number of memory elements defined by a selected number of memory element rows and a selected number of memory element columns, the selected number of memory element rows being the same as the preselected number of video pixel rows and the selected number of memory element columns being the same as the selected number of video pixel columns, the video random access memory being connected with the video monitor such that rows of data are successively read therefrom to the video monitor to generate corresponding rows of pixels of the video display, the video random access memory having a plurality of planes of the memory cells, each with said selected number of memory element rows and columns, corresponding memory elements of each plane storing bits of a corresponding video data value, each plane storing bits of like significance;
• an image buffer memory means having a multiplicity of memory elements which is substantially larger than the number of memory elements of the video random access memory, the image buffer memory means memory elements storing image data values for each of a multiplicity of pixels which exceeds the number of pixels which are displayable at one time on the video monitor;
• a video memory control means for selectively causing rows of memory elements of a subregion of the image buffer memory means to be transferred to corresponding rows of the video random access memory, the subregion having substantially the same number of rows and columns of memory elements as the number of rows and columns of memory elements of the video random access memory means, the video memory control means causing a row of data values to be transferred from the image buffer memory means subregion to the video random access memory in response to each horizontal synchronization pulse such that a row of memory elements of the video random access memory means is updated with memory values from the image buffer memory means concurrently as another row of video data values is read out from the video random access memory to the video monitor responsive to each horizontal synchronization pulse;
• a means for indexing a starting address of the image buffer memory means subregion in response to a vertical synchronization pulse such that the image buffer memory means subregion is indexed and image data values from an indexed subregion row of memory elements updates the video random access memory means row in response to each subsequent horizontal synchronization pulse.