Subtitles refer to text from either a screenplay or transcript of the dialogue or commentary in television programs, video games, films, and the like, usually displayed on the screen.
They can be a form of a written rendering of the dialogue in the same language, with or without added information, to help viewers who cannot understand the spoken language.
In addition, it helps viewers who are deaf or have accent recognition problems to follow the dialogue.
Nowadays, the subtitlers can easily access each video frame instantly because they work with specialized computer software and hardware.
This specialized computer allows the subtitlers to create the subtitles and decide where each should appear on the device’s screen.
For cinema films, the task of showing subtitles is traditionally done by separate technicians.
Today, the specialized computer software subtitlers use allows them to generate a subtitle file containing the actual subtitle and position markers.
The position markers indicate where each subtitle should appear and disappear.
If the subtitles are to be used for traditional cinema films, these markers are usually based on film length (measured in frames and feet).
It can also be based on timecode if it works for electronic media (for example, DVD, Video, TV).
The following are several ways to add the finished subtitle files to the picture:
- Enclosed in the vertical interval and later superimposed on the picture by the end-user with the help of a decoder built into the TV or an external decoder (closed subtitles on TV or video);
- Directly into the picture (open subtitles);
- Or converted (rendered) to BMP or TIFF graphics later inlaid on the picture by the end user’s equipment (As part of a DVB broadcast or closed subtitles on DVD).
Individuals can create subtitles using freely available software, such as MovieCaptioner for Mac/Windows, Subtitle Composer for Linux, and Subtitle Workshop for Windows.
The subtitles are then embedded into a video file with programs such as VirtualDub. The VirtualDub program connects with VSFilter, which could also display subtitles as soft subs.
The soft subs are supported in many software video players.
Categories of Subtitles
Narrative
Narrative subtitles are the most common subtitles in which spoken dialogue is displayed. They are most commonly used to translate a film with one spoken language and the text of a second language.
Hearing Impaired subtitles
They are sometimes abbreviated as SDH or HI. The hearing subtitles are intended for the hearing impaired.
The hearing subtitles provide information about music, off-screen speakers (e.g., when a gunshot is heard or a doorbell rings), and environmental sounds.
In other words, the hearing-impaired subtitles point to the sources and the kinds of sounds from the movie.
These sources and kinds are usually put inside brackets to delimitate them from actors’ dialogues.
For example: [mysterious music], [sound of typing on a keyboard], [woman screaming], [glass breaks].
Forced subtitles
Forced subtitles are common in movies. They are only provided when the characters speak a foreign or alien language, a flag, or a sign.
It also provides subtitles when another text in a scene is not translated in dubbing and localization.
These can be certain time/location identifiers, dialogues, textual graphics, etc., that aren’t explained in the audio.
For instance, In Steven Spielberg’s Amistad, the dialogue of the Spanish slave traders is subtitled, while African languages are left untranslated.
Content subtitles
These subtitles are a staple of the North American Secondary Industry (non-Hollywood, which is often low-budget). The content subtitles add dictation missing from a dialogue or filmed action.
Such films usually have general low-budget allowances, making it more practical to add overlay subtitles to fill in the information.
They are most commonly seen in Canada’s MapleLeaf films as optional subtitles and in America’s Maverick films as forced subtitles.
Content subtitles also appear at the end of films like Gods and Generals and at the beginning of higher-budget films like Star Wars.
Titles
Titles are a category of subtitles typically used by dubbed programs. They provide only the text for any untranslated on-screen text. They are most commonly seen as forced subtitles.
3D subtitles
This category of subtitles combines the standard subtitle position along the picture’s X and Y axes with a third position along the Z axis.
The third positioning allows the subtitle to “float” before the 3D image. This option is available in 3D Blu-ray releases and Digital Cinema.
Types of Subtitles
Subtitles are known to exist in two forms:
- Open subtitles: These are “open to all” and cannot be turned off by the viewer;
- Closed subtitles: These are designed for a certain group of viewers and can usually be turned on/off or selected by the viewer. Examples include Teletext pages, DVB Bitmap subtitles, DVD/Blu-ray subtitles, and U.S. Closed captions (608/708).
While sharing content, subtitles can appear in one of three(3) types:
Hard subtitles
This type of subtitle is also known as open or hard subtitles. The hard subtitle text is irreversibly merged into the original video frames, so no special playback software or equipment is needed.
Therefore, complex transition effects and animation can be implemented, such as karaoke song lyrics using various fonts, colors, animation, sizes (like a bouncing ball), etc., to follow the lyrics.
Nevertheless, these subtitles cannot be turned off unless the original video is included in the distribution, as they are now part of the original frame.
As a result, several variants of subtitling, such as in multiple languages, are impossible.
Pre-rendered subtitles
They are also known as closed subtitles. Prerendered subtitles are used on Blu-ray and DVD (though they are in the same file as the video stream).
They are separate video frames overlaid on the original video stream while playing.
It is possible to have multiple language subtitles and switch among them or turn them off, but the player has to support such subtitles to display them.
Besides, subtitles are usually concealed as images with several colors and minimal bitrate; they typically lack anti-aliased font rasterization.
Besides, changing such subtitles is hard, but special OCR software, such as SubRip, exists to convert them to “soft” ones.
Soft subtitles
They are also known as closed subtitles and softsubs. They are separate instructions, usually a specially marked-up text with timestamps to be displayed during playback.
Soft subtitles require player support. Multiple incompatible (but usually reciprocally convertible) subtitle file formats exist.
Softsubs are relatively easy to change and create and are usually used for fansubs. Text rendering quality can fluctuate depending on the player but is generally higher than prerendered subtitles.
Also, some formats introduce text encoding troubles for the end-user. This happens if different languages are used simultaneously, such as Asian and Latin scripts.
In other arrangements, digital video subtitles are sometimes called external and internal.
They are called external if distributed as a separate file (less convenient, but it is easier to edit/change such files).
We can also call them internal if they are embedded in a single video file container along with video and audio streams.
