Whenever there's continuous instances of speech in a video, such as a long explanation or a fast-paced conversation between people, subtitles are required to appear closely after each other to stay synchronised to the dialogue.
However, many platforms (such as Happy Scribe) enforce short, mandatory gaps between subtitles that are supposed to follow immediately after another.
For example, in the image below, the gaps are the spaces between subtitles 05 and 06, as well as 06 and 07. While each subtitle could have appear directly after its previous one, there is a short pause (a gap) between them.
Why use gaps?
The purpose of these gaps is to give the viewer time to realise a new subtitle has started by introducing a fraction of a pause between the previous and the next one. The viewer will realise the subtitles are flashing on and off the screen, even if it's only in the blink of an eye. This proves especially helpful when two succeeding subtitle events look very similar in size and shape to each other.
What are frame gaps?
To keep the subtitles in sync with the audio, gaps should be minor and are often expressed in frames (we refer to them as "frame gaps"). Frames are the static images that make up a video. Usually 24 or sometimes 30 frames follow each other every second to create a moving image.
Put simply: if a video was a flip book, the frames would be each unique page inside that flip book. If there were 5 subtitles in that flip book, each spread over multiple pages, we would leave two pages without subtitles between every new subtitle. That way we'd have time to realise there has been a change in text. This is how subtitle frame gaps work.
Frames are usually the preferred unit for subtitle gaps because they're noticeable and universally understood units of video footage.
What's the ideal frame gap?
A 2 frame gap is always recommended and is incorporated in the Happy Scribe presets. That gives enough time for the eyes to realise a new subtitle event has started, but it's small enough to avoid causing a delay in the off or onset of the subtitles according to what's being said on screen.
Your specific project might require larger frame gaps, but please note that this can affect the timing of your subtitles as well as increase the Characters per Second (CPS), since there is less room for stretching subtitle capsules when there's a higher gap to be enforced between them.
If you're using Style Guides and you want to ensure that your subtitles are still in sync with the audio, we recommend you stick to our default frame gap of 2 frames.
How does the editor account for frame gaps?
Whatever you pick— whether you leave it at 2 frames or change this gap— any noticeable gaps are automatically enforced in the editor, meaning that neither you nor our linguists will be able to reduce them.
We hope this offers you perfectly legible subtitles for all your audiovisual projects!