Patent ID: 7643694

Claim:
A method of processing Discrete Cosine Transform (DCT) compressed data corresponding to a representation of an image, the compressed data including a plurality of coded units encoded in a first sequential order that corresponds to a first representation of the image in a first orientation, the method comprising acts of: iteratively decoding subsets of the plurality of coded units in a second sequential order that corresponds to a second representation of the image in a second orientation that is rotated by a multiple of ninety degrees relative to the first orientation, the act of iteratively decoding being performed by a processor based solely upon the compressed data and including decoding a first subset of the plurality of coded units that corresponds to a first contiguous portion of the second representation of the image in the second orientation to provide first quantized DCT coefficient data corresponding to each coded unit in the first subset of the plurality of coded units, and decoding a second subset of the plurality of coded units that conesponds to a second contiguous portion of the second representation of the image in the second orientation that is contiguous to the first contiguous portion to provide second quantized DCT coefficient data corresponding to each coded unit in the second subset of the plurality of coded units; rotating the first quantized DCT coefficient data corresponding to each coded unit in the first subset of the plurality of coded units to provide first rotated quantized DCT coefficient data corresponding to each coded unit in the first subset of the plurality of coded units; inverse quantizing and inverse discrete cosine transforming the first rotated quantized DCT coefficient data corresponding to each coded unit in the first subset of the plurality coded units to provide rotated spatial data corresponding to each coded unit in the first subset of coded units; storing the rotated spatial data corresponding to each coded unit in the first subset of coded units in a first memory dimensioned to store less than all of the rotated spatial data corresponding to each coded unit in the plurality of coded units; and providing, prior to the act of decoding the second subset of the plurality of coded units, the rotated spatial data corresponding to each coded unit in the first subset of coded units to a display device.