Issues with certain video formats (SDL 1.2.16)

[samo790]

By working on an SDL/GL video outputs for MPlayer we found a problem with latest SDL1
Using the latest SDL 1.2.16 certain video formats start showing garbage on screen (in fullscreen)

This is the strange effect recordered on camera:
https://uploadnow.io/files/Tm6DkWz

By investigated a bit more we noted that the issue are not effecting every kind of video formats, for example with AVI files the graphical glitch are not visibile at all, while instead MPEG and MP4 files seems suffered of this problem!

As we reverted back to the latest SDL 1.2.15 everything gone, and all works as they should, so most probably we have a regression here

(Originally posted on: https://github.com/AmigaPorts/SDL/issues/197)