MANIPULATING SUB-PICTURES OF A COMPRESSED VIDEO SIGNAL

摘要

The invention relates to manipulation of sub-pictures ( 303 ) in a picture such as a mosaic screen ( 301 ). An apparatus comprises a sub-picture generator ( 105 ) connected to a mosaic screen generator ( 107 ), which generates the mosaic screen (301 ) from the sub-pictures. The mosaic screen ( 301 ) is by a video compressor ( 111 ) divided into uncompressed picture blocks such that each block only comprise video data from one sub-picture. The picture blocks are compressed using a block compression scheme such as MPEG-2. The apparatus further comprises a video manipulation processor ( 113 ), which manipulates the sub-pictures by manipulating the association between control data in the video signal and the compressed picture blocks. The video data of the compressed picture blocks are not affected whereby de-compression and new compression is avoided.