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instruction. The reference frame is panned, rotated and zoomed in accordance to GMC warp points to create a prediction of how the following frame will look. Since this operation works on individual pixels (rather than blocks), it is capable of creating predictions that are not possible using
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offers 1 warp-point GMC encoding: This enables easier hardware support in DivX certified and non-certified devices. But as 1 warp-point GMC limits the global transform to panning operation only (since panning can be described using blocks), this implementation rarely improves video quality.
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specification - designed as a successor to MPEG-4 ASP. Most of GMC's benefits could be obtained via better motion vector prediction. GMC also represents a large computational cost during encoding which yields relatively minor quality improvements.
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Due to the extra decoding CPU cost of global motion compensation, most hardware players do not support global motion compensation.
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