would like explanation on why some movies have constant pulsating effect

[STARSCREAM]

Ok, so this has been bugging the heck out of me and I can't find an answer to it. I'd like for someone knowledgeable to explain to me why some movies have constant pulsating effect to it?

For instance, The Wizard Of Oz blu-ray has this constant what appears to be brightness fluctuations or something that is especially noticeable on backgrounds and things were it gets bright then dim etc. It it horribly noticeable and distracting at the first on the sepia toned scenes but you can also see it throughout the movie.

Another blu-ray is Ghostbusters. It does the same thing throughout and it very distracting as well. I've noticed newer movies don't do it though there are some with scenes that do it occasionally but not throughout the entire movie like the ones I've mentioned. Is it due to the type of film used, lighting, color timing,????? It is very distracting to me.