I have been experimenting with different brands of dvd-r recorded on sony dru500a to play on denon 2500.
It seems that all brands work but on and off. I thought variation would be brand connected.
I have tried traxdata, princo and sony.
Only 1 sony : worked
7 princo : all work but 2
2 traxdata : 1 work/ 1 not
The ones that don't work, do work in sony burner / dell laptop.
A friend of mine has the same dvd-player: same results.
Compatibility per disk is completely predictable once established.

Are there any brand differences at all, or is it just russian roulette?
Can I expect the ones that do not work to work in future standalone dvd-players?