Patent ID: 7792190

Claim:
A method comprising: (a) transforming a sequence of frames of image data into a video stream, wherein one of the frames of image data is a selected frame of a first pixel resolution, and wherein the video stream is of a second pixel resolution, the video stream including a sequence of I-frames, wherein the first pixel resolution is greater than the second pixel resolution, and wherein a reduced resolution version frame of said selected frame is present in the video stream in the form of one of the I-frames; (b) transforming said selected frame from a first domain to a second domain to obtain a second frame of image data; (c) quantizing the second frame of image data to obtain a third frame of image data; (d) inverse quantizing the third frame of image data to obtain a fourth frame of image data; (e) inverse transforming the fourth frame of image data from the second domain to the first domain and thereby obtaining a fifth frame of image data; (f) zooming up the fifth frame of image data to the first pixel resolution to obtain a sixth frame of image data; (g) differencing said selected frame and the sixth frame and thereby generating a frame of difference information, the frame of difference information being associated in one-to-one correspondence with said one of the I-frames; (h) incorporating the frame of difference information into the video stream; and (i) repeating steps (b) through (h) such that some of the I-frames have associated frames of difference information and such that others of the I-frames do not have associated frames of difference information.