why HKDVD may be played in one DVD player and not in another DVD player?

[neoEIN]

I'm finding more and more of my HKDVDs can be played in one player and then not the other player. Does it mean the HKDVD encoding is not good? Or, I need to buy a new DVD player? Like the MAC new FY perfect set Seiryu set, the last 4 eps in disk 1 and last 2 eps in disk 3 simply cannot be played on my standalone DVD player but play fine in my laptop player. My instant response has been I should avoid buying new MAC DVD series because they are badly encoded.

I know I've read threads before ppl complaint that some episodes of some disk of some series just couldn't be played. But, only recently I have my own share of such headache.

What part of HKDVD that introduces such no-playable problem comparing to R1/R3?

Thanks.

Ps. I've read Kak's AN broken DVD thread but it's too much work, too complicated, and I prefer to watch HKDVDs on TV.