Is ghusl required for prayer if fluid is discharged—after watching foreign films that contain pornographic scenes—without masturbating, and what is the interpretation and solution for this?

It is not permissible to watch these films, as they are among the forbidden acts that must be avoided, in compliance with the words of Allah Almighty: "Tell the believing men to reduce [some] of their vision and guard their private parts." Looking at these films may lead to falling into something greater, so one must desist from them and offer sincere repentance. If you did not practice masturbation, then what exits is impure prostatic fluid (madhiy) which necessitates washing whatever it soiled and performing ablution for prayer, but it does not necessitate ghusl (ritual bath).