×

Efficient fixed-point approximations of forward and inverse discrete cosine transforms

  • US 8,571,340 B2
  • Filed: 06/21/2007
  • Issued: 10/29/2013
  • Est. Priority Date: 06/26/2006
  • Status: Active Grant
First Claim
Patent Images

1. A method comprising:

  • scaling each coefficient in an 8×

    8 matrix of encoded coefficients by one of a factor A, a factor B, a factor C, a factor D, a factor E, a factor F, a factor G, a factor H, a factor I, or a factor J in order to produce a matrix of scaled coefficients,wherein A=1024, B=1138, C=1730, D=1609, E=1264, F=1922, G=1788, H=2923, I=2718, and J=2528;

    using repeated applications of a fixed-point scaled one-dimensional transform to transform the matrix of scaled coefficients into a matrix of transformed coefficients;

    right-shifting transformed coefficients in the matrix of transformed coefficients in order to produce a matrix of adjusted coefficients;

    wherein each adjusted coefficient in the matrix of adjusted coefficients approximates a corresponding value in a matrix of values that would be produced by applying an ideal two-dimensional inverse discrete cosine transform (“

    IDCT”

    ) to the matrix of encoded coefficients;

    displaying an 8×

    8 block of pixels, wherein each pixel in the 8×

    8 block of pixels includes a pixel component value based on an adjusted coefficient in the matrix of adjusted coefficients.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×