You Tube does have a
guide and
here
I say that because they have changed thier own size and format rules and previous advise given on n here might be out of date
The simple answer though is that any no of formats will get you there depending on your own software and how large the resulting file size is
A lot of experimenting is the way foward
Dont use Pinnacles You tube uploader
Output it yourself to any of the formats ( MP4 ect) and then manually upload
Pinnacle is more than likely using highly compressed but quality killing defaults in its uploader