When burning:
When you are burning DVD's your main concern is compatibility. There is a difference between a PC's DVD drive and a DVD player.
First rule that i follow whenever burning DVD's for whomever is to burn them at the lowest speed. Thou i found that today's DVD burners burn their DVD's with much higher compatibility than just few years ago. Still - old DVD readers might have problems with reading DVD's that where burned fast - this goes especially to the cheap DVD players that could/can be bought for peanuts. And some older LG players ) from my personal experience )
This falls down to the DVD readers error correction system. ( DVD burners do not make 1 to 1 burns, they make errors during the process, the faster you burn, more errors are likely to be made )
PC drives are commonly more compatible with whatever you feed them. Whenever a DVD is damaged/has a defect or is just not created properly, a PC is capable of overcoming that ether directly, thanks to the drive error correction system or though software that user uses to play his things and can just skip frames without you noticing it.
DVD players are limited, and some of them are deliberately created to not read burned DVD's ( i dont know if that still holds at present ).
Further to that DVD player is enforced with restrictions that i think where created to limit piracy ( or where developed from corporate fights ).
Those are called Encoding Systems and there are 3 types of them:
PAL
NSTC
SECAM
PAL being the most popular used in most of Asian and Europe's Countries, also used in Australia. Whenever you want to extend your DVD compatibility, you will have to consider those aspects. But most likely you will be burning your DVD's in PAL format, since it is the only standard used in Australia.
more info