Patent ID: 7403561
Filing Date: 2008-07-22
Classification: H04N

Abstract:
1. A method for fixed bit rate, intraframe compression of video, including a sequence of images, comprising, for each image: transforming portions of the image to generate frequency domain coefficients for each portion; selecting a quantization matrix according to the desired bit rate; determining a bit rate for each transformed portion 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 to achieve 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; wherein entropy encoding comprises: