Compression artifact: Difference between revisions

Revision as of 05:40, 13 December 2004

Revision as of 05:54, 23 December 2004

Line 9:

Where the [[DCT]] image transform is used, for example, they are often 8x8 pixel squares, containing a stripe or "checkerboard" pattern.

Where predictive coding of motion pictures is used, as in [[MPEG-1]], compression artifacts tend to remain on several generationgenerations of decompressed frames, leading to a "painting" effect being seen, as if the picture was being painted by an unseen artist's paint-brush.

Where motion prediction is used, as in [[MPEG-2]] or [[MPEG-4]], compression artifacts tend to move with the [[optic flow]] of the image, leading to a peculiar effect, part way between a painting effect and "grime" that moves with objects in the scene.