Browse Prior Art Database

Method to Build Video Capture Controller Suitable for Movie Image Processing by Software

IP.com Disclosure Number: IPCOM000117661D
Original Publication Date: 1996-Apr-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 69K

Publishing Venue

IBM

Related People

Shiratori, T: AUTHOR

Abstract

Disclosed is a method for building a video capture controller suitable for movie image processing by software. It is required to minimize synchronization time between image acquisition by hardware and image processing by software. Furthermore, because software processing speed may vary because of system load change, it is required to keep an acquired image as long as it is needed. The disclosed method resolves these requirements by introducing intelligent Direct Memory Access (DMA) function.

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Method to Build Video Capture Controller Suitable for Movie Image
Processing by Software

      Disclosed is a method for building a video capture controller
suitable for movie image processing by software.  It is required to
minimize synchronization time between image acquisition by hardware
and image processing by software.  Furthermore, because software
processing speed may vary because of system load change, it is
required to keep an acquired image as long as it is needed.  The
disclosed method resolves these requirements by introducing
intelligent Direct Memory Access (DMA) function.

      The Figure shows an example of this video capture controller,
and the following steps describe how this controller works:
  1.  Each block in memory contains one image.
  2.  Each memory block has a corresponding flag in video capture
       controller.
  3.  Each flag represents the status of corresponding memory block,
       and its value is one of "usable(empty)", "acquired", "in-use"
and
       etc..  Each flag also has a time-stamp area.
  4.  An application program initializes the controller by presetting
       DMA commands for memory blocks allocated for the application.
       Corresponding flags are also preset to "usable(empty)".
  5.  The application software requests the controller to start movie
       image acquisition.
  6.  The video capture controller continuously DMA-transfers each
       acquiring image into a memory block whose flag is
       "usable(empty)", and the controller changes a value of the
flag
       to "acquired" when transfer completes.
  7.  The application program observes the flags.  If the application
  ...