How to make rendering loop selections work in Movie Studio Platinum 13? I want to render just 10 seconds of my 1920x1080 movie to create the best quality preview for a demo. But rendering process takes the same time as rendering the entire movie (35 minutes). 

Why is it taking so long? 

A guess - is Movie Studio rendering the entire file and then just cropping away the unselected part? How do I render the selection only?

Here is what I do:


select a 10 seconds region in the timeline
go to menu -> Project -> Make movie
pick option Save it to my hard drive
pick format mp4
enable the checkbox "Render loop region only"
click Advanced options and pick Sony AVC/MVC encoder
pick my preset of choice (1440x1080@30p, 1.333 pixel ratio for anamorphic aspect ratio, 25 FPS, 26 Mbps bitrate)
render
Oh, I found it myself and leaving the answer here in case someone else will get confused by this because the solution is not obvious.

I was setting the checkbox here:



but if I use "Advanced options", Movie Studio ignores this setting!

I have to select it deeper in a hidden dropdown in the "Advanced options" window like this:



And later when rendering the full video, it is important to remember to open that dropdwon again and turn off the region rendering.

Oh, Sony, this is so confusing - two things doing the same, but effective only under specific circumstances.