Browse Prior Art Database

Method for Accurately Capturing the Start of a Video Frame

IP.com Disclosure Number: IPCOM000012701D
Original Publication Date: 2003-May-21
Included in the Prior Art Database: 2003-May-21
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Abstract

Disclosed is a data processing system for accurately capture a video graphics frame.

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Method for Accurately Capturing the Start of a Video Frame

       Whenever a raw video stream is captured (e.g. -Red/Green/Blue pixel data from a computer) to a storage device, a method is needed to determine where the start of the frame is located in the video stream. Also, once the start of the frame is identified, the solution has to inform the device that is capturing the frame (e.g. -a FIFO [first in, first out], memory) in a timely manner so that no pixel data is lost. The solution must also accurately and consistently identify the start of the video frame so that pixel shifting does not occur from frame-to-frame. Finally, the solution must let the capture device know once the frame is complete so that it can stop capturing the pixel data.

     The invention described here describes a simple hardware solution to this problem. The solution can easily be implemented in a small PAL or GAL. The main advantage of this solution is that it is fast enough to ensure that the start of the video frame can be consistently detected at the same point on every frame, thereby eliminating pixel shift from frame-to-frame. Since the solution is also implemented in hardware (versus post processing in software), it is much faster and can respond in real time to video data streams.

Shown in the figure below is the logic diagram for this disclosure.

   The circuit works as follows: On power-up, RESET_N=1. The state of the circuit doesn't matter (don't care).

A microcontroller or similar device...