Patent ID: 6031940
Filing Date: 2000-02-29
Classification: H04N

Abstract:
A method of encoding a sequence of video frames, each video frame represented by an image data array, comprising the steps of:successively processing first and second image data arrays, representing first and second video frames, by:applying a transform to the first image data array to generate a first processed image data array;dividing the first processed image data array into subarrays and encoding the subarrays in a predefined order so as to generate a first set of encoded data representing the first video frame;applying a transform to the second image data array to generate a second processed image data array; anddividing the second processed image data array into subarrays and encoding the subarrays in a predefined order so as to generate a second set of encoded data representing the second video frame;the step of encoding the subarrays of the second processed image data array including, for each of a first subset of the subarrays of the second processed image data array, encoding the subarray by:generating a plurality of encoded representations of the subarray;determining which of the plurality of encoded representations of the subarray is smallest, and outputting the smallest of the plurality of encoded representations of the subarray;the step of generating a plurality of encoded representations of the subarray including:encoding the subarray using a predefined subarray encoding method to generate a first encoded representation of the subarray;generating a differential subarray by subtracting from the subarray a corresponding subarray of the first processed image data array; andencoding the differential subarray using the predefined subarray encoding method to generate a second encoded representation of the subarray;further including:generating a differential test array by subtracting from a predefined test portion of the second processed image data array a corresponding portion of the first processed image data array;determining maximum and minimum values in the differential test array, and generating a difference value representing a difference between the maximum and minimum values;when the difference value meets a predefined threshold criteria, representing the second video frame with a predefined repeat frame code and skipping the steps of dividing the second processed image data array into subarrays and encoding the subarrays.