: This is the call to action. It tells the database to stop looking at the whole library and start narrowing things down.
: This likely refers to "Professional" or "Production" grade content—filtering out user-generated clips or trailers to ensure you get a full-length feature. filter,poprtb,pro,filter,q,movies
: Often a shorthand for "Popularity" or "Rating." This ensures that the results aren't just random, but are the films people are actually talking about. : This is the call to action