Originally Posted by
Animedude5555
Usually problems like that occur on 8x8 pixel groups. These blocks of pixels are part of MPEG based compression algorithms. If there is some bad data in one of these blocks, the entire block can be corrupted for the next several frames (due to temporal compression in MPEG compression, where future frames reuse pixel blocks from previous frames, unless a significant change occurs between frames). Furthermore, pixels in blocks adjacent to these blocks in future frames can get corrupted when part of an image "moves" through the effected area, such as a character walking, the camera shifting, etc (because of motion tracking algorithms in MPEG compression schemes, which allows compression based on motion of various groups of pixels between frames). This will fix itself when the next I-Frame is encountered (basically a JPEG compressed complete image, acting as a reference frame for other frames that come after it).
The presence of such glitches usually are an indication of a problem encoding. Some may be a problem decoding, but if it was encoded exactly to MPEG specs, then no decoder should have a problem with it. So if some (but not all) decoders have a problem, it either means the decoder was horribly written, or the encoder introduced a glitch that affects the playback on some decoders, but not all of them. If all decoders produce the problem during playback, then it definitely is an encoding problem. If you ripped the video from a DVD or digitized a VHS tape yourself, you should re-rip (or digitize) it, possibly with different software the next time. If you got it from a torrent, well you shouldn't be talking about that on this forum, as this forum doesn't support piracy. It is EXTREMELY unlikely that this would exist in a professionally pressed DVD disks sold in stores (like when you go and buy a copy of any studio produced movie from a video store). If you bought it legitimately, and it still has this glitch, it's probably a bad disk and is very rare that these exist, so return it to the store and get another one. If it still has a glitch after you bought a new DVD, then it's probably a no-name generic DVD player with poorly designed circuits made in some China knockoff shop (and likely is an illegal device that violates the patent on DVD technology, because unlike other consumer electronics, every DVD player manufacturer MUST under law sign a license agreement with and pay big bucks to the inventors of DVD technology to be able to use that technology in their player). If you got your DVD movie on Ebay, and it has this glitch, you probably bought a bootleg. Be careful what you get on Ebay, because many people will rip you off with DVD boxes that have legit looking box art and DVD labels (that they probably downloaded off the net somewhere or scanned from their own store-bought copy). Demand a refund from them, and if they refuse, you can assume they are a scammer, and you should report them to Ebay to get their seller's account rejected. Amazon.com is usually a safe place to buy, although some 3rd party sellers sell through them, and some of them may not be legit (though theoretically Amazon has a much better screening policy than Ebay).
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