Forced Subtitles
Forced subtitles appear in many movies and only provide subtitles when the characters speak a foreign or fictitious language, or a sign, flag, or other text in a scene is not translated in the localization and dubbing process. These subtitles, although in less than half of the commercial motion pictures available, are still commonplace.
There is a distinction between "narrative subtitles" and "forced subtitles" in that subtitles in DVD and Blu-ray motion picture media are optional and provide text for all dialog in a movie, while "forced subtitles" are shown regardless of current player setting, typically when movie contains a foreign language scene.
In VHS and early DVD movies the forced subtitles were graphic images that were part of the video itself. Later DVD and all modern Blu-ray use an overlay over the video reading the subtitle text from formatted text. On Blu-ray, each subtitle item has an attribute that specified whether particular subtitle appearance should be forced.
For example, if you are an English Speaking person watching a French film in which all dialog is French, and you are not bilingual, you will wish to have complete narrative subtitles for all dialog in the film.
If you are an English Speaking person watching an English movie with a majority of English speaking characters with a few scenes of characters speaking in a Foreign language, you might find it annoying to have complete narrative subtitles throughout the film. You only require subtitles when the Foreign language dialog is spoken. In this case, you desire "forced subtitles," which are those that only appear in the few foreign language parts.
In the process of digitally archiving their DVD and Blu-ray media into re-encoded video files for storage on a computer or PVR media device, people sometimes neglect, often by accident or due to being ill informed, including the forced subtitles in the movie. They are not automatically captured by many "ripping and encoding" software. The result could be a minor problem of a few scenes without the necessary subtitles or a major problem where enough non-English dialog is not understood, resulting in degrading the viewers understanding of the plot and storyline of the movie.
Including forced subtitles in archived movies is not only a quality control issue, but is in consideration of capturing the movie in its completeness for future enjoyment.
