I have had DVD's that played perfectly and some that didn't play at all. I try them on different players or on my computer or lap top and sometimes it is better, sometimes not. It is always the same place that the picture freezes, dissolves into pixels, whatever, showing that it is the DVD that is wrong and not the player(s).
I have tried making DVD's and found that slowing down the record speed stands a better chance of success with some awkward ones. But in Picture CD's, in varying places there always seems to be some out of a thousand or so that just do not work, no matter what I try.
We are told that DVD's produce a perfect picture, well as good as a 15 year old standard play video on a 4 head VHS machine. I have never had to endure freezes, pixelating, etc with VHS. The many thousands I have had have always played. I can stop them and come back five minutes or five hours later and start watching straight away not having to try and find out how far I had gotten.
Digital TV's. You either have a perfect signal or no signal. There are still places which cannot pick up digital TV in the UK who can pick up analogue. A thunderstorm can ruin a digital picture too, but not an analogue picture. Thankfully, many are now sent by wires rather than dishes, where you could lose the picture in a heavy downpour.