What is artifact: Definition and 14 Discussions

A compression artifact (or artefact) is a noticeable distortion of media (including images, audio, and video) caused by the application of lossy compression. Lossy data compression involves discarding some of the media's data so that it becomes small enough to be stored within the desired disk space or transmitted (streamed) within the available bandwidth (known as the data rate or bit rate). If the compressor cannot store enough data in the compressed version, the result is a loss of quality, or introduction of artifacts. The compression algorithm may not be intelligent enough to discriminate between distortions of little subjective importance and those objectionable to the user.
The most common digital compression artifacts are DCT blocks, caused by the discrete cosine transform (DCT) compression algorithm used in many digital media standards, such as JPEG, MP3, and MPEG video file formats. These compression artifacts appear when heavy compression is applied, and occur often in common digital media, such as DVDs, common computer file formats such as JPEG, MP3 and MPEG files, and some alternatives to the compact disc, such as Sony's MiniDisc format. Uncompressed media (such as on Laserdiscs, Audio CDs, and WAV files) or losslessly compressed media (such as FLAC or PNG) do not suffer from compression artifacts.
The minimization of perceivable artifacts is a key goal in implementing a lossy compression algorithm. However, artifacts are occasionally intentionally produced for artistic purposes, a style known as glitch art or datamoshing.Technically speaking, a compression artifact is a particular class of data error that is usually the consequence of quantization in lossy data compression. Where transform coding is used, it typically assumes the form of one of the basis functions of the coder's transform space.

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  1. rnevels

    Searching for Answers: Finding Help in PF to ID a Stone Tool

    How did you find PF?: Goggle search We recently found this stone object on our property here in NWA, and we were wondering if there was someone in PF that could assist us in identifying if this might be an indigenous stone tool. From a layman’s perspective it seems to be intentionally shaped...
  2. R

    A Hubble Tension and Cosmic Acceleration: A measurement artifact?

    By analyzing 91,742 reported extra-galactic distances and their one sigma uncertainties for 14,560 galaxies, it was found that pairs of reported extra-galactic distances of the same galaxy differ from each other by 2.07 the reported uncertainties on average. In my opinion, this indicates that...
  3. M

    A How can a zipper MRI artifact be limited to a single line?

    he so-called [herringbone or spike MRI artifact][1] on a given example could be traced to a specific point(s) in Fourier space ("k-space"). The idea is that during the acquisition of the image, a certain RF wave emitted by the patient (providing the info about diseased or normal anatomy) had...
  4. S

    Is light speed limit an artifact of the math of measurement

    A delightful video here A lecturer derives special relativity in a world of bats and echo location using a bat (sound) clock. All communication is limited by the speed of sound. (so a parallel of our world and light speed communication) He ends up observing that in no cases for any observer...
  5. Noctisdark

    Is Quantum Mechanics an artifact of our ignorance?

    I've read a lot about QM and studied the math and how it work many and many times in several lectures in several places, but whenever I review what the theory says and compare it to how the measurement work, I come to doubt in the theory it self, I think it can even be explained using classical...
  6. DiracPool

    Is Love Real or Just an Artifact?

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  7. Astronuc

    Fisherman finds 4000-year old artifact

    Fisherman nets 4,000-year-old pagan figurine http://www.grindtv.com/outdoor/outposts/post/fisherman-nets-4000-year-old-pagan-figurine/ Nikolay Tarasov pulls Bronze Age artifact, carved in bone and said to be worth more than its weight in gold, from Siberian river near the community of...
  8. L

    Design pattern i have found on an old artifact.

    Hi everyone, Recently i went to visited my grandfather and he brought me to his room where he pulled out an old artifact that he got from his father that got it from his father. He says it is from Egypt. it like a circle container and has a symbol on it. The symbol really intrigued me so...
  9. Z

    ED-XRF spectra - recurrant artifact below 0 keV?

    Hello, I can't seem to find a comprehensive explanation for this recurring phenomenon on my XRF spectra graphs. It's a high intensity peak that occurs seemingly below the 0 keV energy mark. And it seem to be common to many graphs, yet nowhere seems to say what it actually is, aside from a...
  10. M

    Big Bang Big Schmang, astronomical redshift is an artifact of distance

    http://img76.imageshack.us/img76/2711/virgocluster.jpg Look at this image of the Virgo cluster of galaxies, for images of galaxies extending as far as the eye can see, some appear to exist in a swarm around the sub cluster at the core, others are in streamers and wisps of galaxies extending...
  11. E

    Could GR's background independence be a theoretical artifact?

    Could GR's "background independence" be a theoretical artifact? ==quote from Rovelli "Unfinished Revolution" (2006) page 2== ...Others, on the other hand, and in particular some hard–core particle physicists, do not accept the lesson of GR. They read GR as a field theory that can be...
  12. C

    Humans are artifact adoring artisans

    Humans are artifact adoring artisans Humans are meme (idea) adoring creators. Humans create symbols (abstract ideas) upon which they place value sufficient for killing and dying. Americans create a flag (an artifact of cloth) which symbolizes the value they place in a nation...
  13. Y

    News Masonic Symbol found in Temple Mount artifact

    Here's one for the conspiracy theorists:
  14. check

    Alien artifact found in Tunguska site

    http://www.mosnews.com/news/2004/08/10/tunguska.shtml According to the Moscow News, the first ever debris of the object that exploded over Tunguska, Russia in 1908 has been recovered. The article says that a large black, metallic box has been found and has been sent to a lab for analysis...