I have asked this a few times elsewhere. If I have asked here then sorry. So far I have not really found anything out.
This is not a gripe, but a serious question. If I am missing something and not seeing the problem it could be at least a nuisance.
I am always reading and hearing that I must set the Project Properties right: usually to the same as my source. But I have never found out why.
As far as I can see it has no effect on the output, as that is decided by the renderer. The only effect I _have _ seen is when I set the AR of the PPs to a stupid ratio, like 700 * 200 and suddenly in mucked up the rendered result, no matter what the render settings. But that seemed more of an aberration than the norm.
Even though there are claims that it will help editing smoothness, I have found that if I alter the frame size or whatever, in the end it's the Preview quality that makes most difference.
And what if I have various sources? #1 is 1080 50p, #2 is 720i etc. Does the whole thing go to pot? From the exhortations I have seen to "get it right" it would seem so, but I have not seen it yet.
I really would like to hear the truth of this, or be pointed to a source of info about it.
Thanks in advance.