Special:Badtitle/NS90:Talk:Kdenlive/Manual/Projects and Files/Project Settings/Difference between project profiles and render profiles

It has never been clear to me what the difference between project profiles and render profiles is.

This page says

You should carefully choose your project format and select the one that fits better with what you want to output. All video operations on the project (like compositing, scaling, etc) will then use this profile.

For example, if your goal is to create a DVD, you should use a DVD profile with the correct frame rate (PAL / NTSC) and display ratio (widescreen or not).

But why should we do this? Surely it is the rendering that defines what sort of video we get.

I guess this page goes some way to explain what the project profile provides. Is it saying that if you don't match the project profile to the profile you render with at the end then the video operations that Kdenlive does will not be accurate because the frames per second or line count will not be correct ?

Can we be more explicit about what the project profile does?