Patent ID: 7729423

Claim:
A method for fixed bit rate, intraframe compression of video, including a sequence of images, comprising, for each image: segmenting the image into a plurality of portions; transforming the portions of the image to generate frequency domain coefficients for each portion; selecting, from a plurality of stored quantization matrices each defined for a respective one of a plurality of bit rates, a quantization matrix for the image according to a desired bit rate from the plurality of bit rates for the sequence of images; determining a bit rate for each transformed portion of the image using a plurality of scale factors; estimating distortion for each portion according to the plurality of scale factors; selecting a scale factor for each portion to minimize the total distortion in the image, while achieving a desired bit rate; quantizing the frequency domain coefficients for each portion using the selected quantization matrix as scaled by the selected scale factor for the portion; entropy encoding the quantized frequency domain coefficients using a variable length encoding to provide compressed data for each of the defined portions; and outputting the compressed data for each of the defined portions to provide a compressed bitstream at the desired bit rate.