Patent ID: 7254174
Filing Date: 2007-08-07
Classification: H04N

Abstract:
1. A process for generating an MPEG output bitstream from an MPEG input bitstream having a first resolution, said MPEG output bitstream having a second resolution modified with respect to the first resolution of said MPEG input bitstream, the process comprising the operations of: distinguishing, in said MPEG input bitstream, first portions that substantially do not affect and second portions that substantially do affect variation of the resolution of the MPEG output bitstream; subjecting said second portions of the input bitstream to an inverse-quantization operation to obtain inverse-quantized second portions of the first resolution; subjecting said inverse-quantized second portions of the first resolution to motion compensation in a DCT domain to obtain motion-compensated second portions of the first resolution; subjecting said motion-compensated second portions to a first operation of modification of the resolution by filtering said motion-compensated second portions in a discrete cosine transform domain to obtain resolution-modified second portions in the second resolution, wherein said filtering operation in the domain of the discrete cosine transform includes the operations of: storing said resolution-modified second portions; and obtaining resolution-remodified second portions by subjecting the stored resolution-modified second portions to a second operation of modification of the resolution that brings back the resolution of the stored data from said second resolution to said first resolution, wherein subjecting said inverse-quantized second portions of the first resolution to motion compensation in the DCT domain includes using the resolution-remodified second portions as a prediction signal when motion compensating said inverse-quantized second portions of the first resolution.