noun
live-action film
A film using real actors and physical sets, as opposed to animation or CGI. The most common meaning.
そのアニメの実写映画が来年公開される。
A live-action film adaptation of that anime will be released next year.
noun
film using real footage
A broader, less common sense: a film that incorporates footage of actual events or real scenes, not necessarily a narrative live-action movie. May overlap with documentary or newsreel usage.
この実写映画は実際の災害の映像を使っている。
This film uses real footage of the actual disaster.