Complex sentence: In some movies the title card does not appear until the end: in such cases one cannot refer to the entire movie as the "opening"; the term "cold open" in these instances refers to the opening moments or scenes.
Split into simpler sentences: In some movies the title card does not appear until the end. In such cases one cannot refer to the entire movie as the "opening"; the term "cold open" in these instances refers to the opening moments or scenes.