Macrovision was first used on VHS tapes in 1984 to copy protected video on VHS tapes, it is simply a video error inserted into the video stream of most commercial VHS tapes. This does not affect how it looks when viewing it on a TV; TV’s are very forgiving of this error. Note that there are some exceptions; this did affect some older TVs when first introduced. What it will affect when attempts to copy a commercial VHS tape from one VCR to another. This manifests as video that jumps frames, video flashing from bright to dark such as the strobing affect I described above. Some of these symptoms very closely resemble a tracking problem. They can however vary widely especially with capture devices, some may simply put up screen stating the video is copyright protected.
Many DVDs contain Macrovision, an analog copy protection. When a DVD player plays a DVD encoded with Macrovision, the DVD player will output a video signal which is incompatible with analog recording devices, such as VHS tape recorders. Macrovision is not a digital protection, so it has no effect on software which is designed to copy a DVD.
Most third party decrypting applications can remove Macrovision from the DVD. The removal could be done on the fly (while copying takes place) by tools like CloneDVD, or as a separate process which rips the DVD contents to a hard drive folder (Using DVD Ghost) prior to the DVD being copied. Macrovision is static entities which cannot change. If they could change, hundreds of millions of DVD players would not know how to play the modified DVDs. So this brings up a couple of interesting questions.