blocking artifacts


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blocking artifacts

A distortion that appears in compressed video material as abnormally large pixel blocks. Also called "macroblocking," it occurs when the encoder cannot keep up with the allocated bandwidth. It is especially visible with fast motion sequences or quick scene changes.

Video uses lossy compression, and the higher the compression rate, the more content is removed. At decompression, the output of certain decoded blocks makes surrounding pixels appear averaged together and look like larger blocks. As TVs get larger, blocking and other artifacts become more noticeable. See artifact and pixelated.


Before and After
The lines at the edge of the original frame are used to point to the blocking artifacts, which are removed with Algolith's MPEG Noise Reduction system. Both images are enlarged to show details. (Image courtesy of Algolith inc., www.algolith.com)
References in periodicals archive ?
The blocking artifacts resulting from W and the small halo induced by the DT-CWT need to be eliminated.
However, the minimum [l.sub.2]-[l.sub.1] norm reconstruction model has different convergence performances for various block sparse degrees, giving rise to blocking artifacts of reconstructed image.
The reconstructed images by our ABCS system have better surfaces and edges of objects, but there are many blocking artifacts in a whole image.
When sampling rate is set to 0.3 or 0.5, some blocking artifacts are observed on both large and small clock, but the resultant images display better visual effect with sampling rate 0.7.
Key words: high definition video, blocking artifacts, deblocking filter, H.264/AVC, 1080p
Consequently, videos encoded using the HEVC standard may suffer from blocking artifacts, ringing, color deviations, and image blurring.
However, BDCT coding technique usually produces blocking artifacts, especially at low bit rates.
"Removal of Blocking artifacts in DC and AC filtering", IEEE Conference on Signal Processing, 1: 229-232.
The cause of blocking artifacts in lossy compression is artificial boundaries between neighboring blocks induced by BDCT.
So the efficiency problem of conventional APBT algorithm and the blocking artifacts in DCT can be solved by the parallel APBT algorithm.
It can be observed that edge and texture regions appear the obvious blurring and blocking artifacts. Therefore, to retain the clear edge and texture details, in addition to using the sparse priori knowledge, the other priori knowledge requires also to be added.
Whereas block edges may not always be consistent with the heterogeneous object edges, and thus blocking artifacts are usually perceived in the regions where one block has a significantly different motion compared with its neighbors.