Quick Question,

if putting a 2 hour concert on dvd, with menu's and one soundtrack (I think Stereo, not 5.1), will it be good quality, or should I be looking at a dual layer disc?

It would be for a professional release, so we can't risk having bad quality...
Don't know if we will be doing it with Final Cut Studio or Adobe, doubting at the moment, but prefering Final Cut Studio.

Evidently, a dual layer will hold twice as much data, so you will have to compress a lot less. To fit two hours of video with menus and stereo audio at say 224 kbps, you will have to go under 4.5 Mbps video on a DVD5, while you could go 9 Mbps on a DVD9 (but don't go over 8 Mbps or you will have issues with some players). The problem is, unless you use a professional duplication facility, you will have issues with dual layer discs - burned dual layers are known for compatility problems with lots of players.

So my advice is: either replicated dual layers, or duplicated single layers. If you don't mind spending a little more, you could also break up the concert and use two single layers and sell them in a double album.

You will have enough space for an average of 4.5MBps. I think single layer should be fine unless you have challenging footage; encoders have progressed to the point that they can yield great quality at the bit rate.