DVD Playback

[William Dee]

I am having problems with playback of DVDs on standalone DVD player. My PC can play the DVDs OK, but standalone is giving a flickering type screen. The audio is fine. If the problem was on your TV it would be like you needed to adjust the vertical hold.
I have bought 4 DVDs from this source and 1 is OK but the other 3 flicker. Can someone help?
Thanks in advance.