Patent ID: 6711212
Filing Date: 2004-03-23
Classification: H04N

Abstract:
A video system, comprising:(a) transcoder means for (i) receiving multiple incoming encoded digital video signals respectively sent over plural transmission paths from a plurality of video devices, (ii) processing said received video signals and (iii) combining the processed video signals into an output video signal comprising a single coded video bit stream, respective portions of said output video signal corresponding to said video signals sent from said plurality of video devices constituting sub-windows of said output video signal; and (b) means for transmitting the output video signal through said transmission paths to said plurality of video devices, sub-window; â€ƒwherein said transcoder means comprises: (i) means for classifying said sub-windows into active sub-windows and static sub-windows; and (ii) means for generating said output video signal by (1) transcoding frames of said active sub-windows while skipping transcoding of frames of said static sub-windows and substituting a latest corresponding encoded sub-window for a skipped sub-window to approximate the skipped sub-window, and (2) obtaining outgoing motion vectors of said output video signal from incoming motion vectors of said active sub-windows and said static sub-windows by obtaining a motion vector of a non-aligned macroblock, which is not aligned with segmented macroblock boundaries in said sub-windows, by a dominant vector selection operation comprising pre-filtering out unreliable motion vectors of said segmented macroblock boundaries and selecting the one of said segmented macroblock boundaries having the largest overlapping activity as the dominant block, and selecting the motion vector of said dominant block as said motion vector of said non-aligned macroblock.