Patent ID: 6542643
Filing Date: 2003-04-01
Classification: H04N

Abstract:
A method for measuring activity of a macroblock in a direct cosine transform domain for a selected component of a video picture, the method comprising:dividing the macroblock into blocks of data in the discrete cosine transform domain before quantization, and separately storing each block of data in a memory; reading each block of data stored in the memory for obtaining respective coefficients; multiplying an absolute value of each coefficient by a selected mask of words comprising a number of words not exceeding a number of words forming each block; summing results of the multiplications for producing an activity coefficient for each block; calculating a first activity coefficient of the macroblock corresponding to a sum of the activity coefficients produced for each block; and calculating a normalized activity value of the macroblock as the ratio between a sum of double the first activity coefficient with a mean activity coefficient relative to a preceding coded frame, and a sum of double the mean activity coefficient with the first activity coefficient.