Patent ID: 7151887
Filing Date: 2006-12-19
Classification: H04N

Abstract:
1. A copy controlling system in a device for recording digital contents compressed and delivered by the MPEG (Moving Picture Coding Experts Group) standard, comprising: a means for requiring even a discrete cosine transform (referred to as “DCT”) coefficient of the digital contents, in decoding the digital contents; a within-block coefficient controlling means for changing the DCT coefficients within a block, according to attribute information relative to recording restriction of the digital contents; and a means for creating stream data for recording after encoding again the obtained DCT coefficients, wherein the attribute information of the digital contents includes at least one of the following information: recording is prohibited (NeverCopy); since it was recorded once, no more recording is permitted (NoMorecopy); only one recording is permitted (CopyOnce); and recording is free (CopyFree), and said within-block coefficient controlling means turns to all 0, the values of the DCT coefficients within one block other than a DC (direct current) component and a few AC (Alternating Current) components of a low frequency region, based on the attribute information.