Flexible resizing algorithms for video transcoding

Arbitrary spatial resizing of compressed video is a useful transcoding operation that can be used to match the video stream to a low bandwidth channel or to end user devices with a different resolution from that of the original source material. By performing this transcoding in the discrete cosine transform (DCT) domain the computational cost of the operation can be minimized. Our method modifies a recent approach to make it more general (the previous approach could only downsize by integer multiples of 1/8, while our approach removes this restriction and allows resizing by any rational fraction), efficient, and flexible (i.e. tradeoffs between computational cost and final quality can be made) while retaining the ability to downsize from an arbitrary supporting area (thus making the method useful for both intercoded and intracoded frames).