Currently, if Shotcut determines that your machine has only one or two cpu’s, it removes the Parallel processing checkbox (and label) in Export Video, Advanced tab. (It also checks again the number of cpu’s and ignores the setting before starting an export job.)
This can be very confusing when reading documentation, or asking for help (search the web for “shotcut parallel processing” and see for you self) as some users see this feature and some don’t.
IMHO, a better design is to always show the checkbox, have it disabled when parallel processing is not available (add a message saying something “your computer hardware does not support parallel processing”)
Very minor, and I have better things to work on. If you don’t have the check box you cannot turn it off. As simple as that. There are plenty of things that will confuse users in any software more complicated than one single button.
Here is a more thoughtful answer and reason I am not going to change it. If something disabled, a user is going to ask what they can do (implied: within the software) to enable it. If there is no way for one to enable it, someone will report it as a bug. It is bad usability to show something disabled that can never be enabled. It is also hidden on 32-bit builds.
That is not exactly true. When # cores < 3, it sets the MLT render thread count to 1.
