You can use Limecraft to automatically create subtitles for your video clips. AI subtitling is especially useful for processing short-form video. When using square or vertical video resolutions, it is important to modify the styling rules for better readability. In this article you will learn how to set up the subtitle preset and optimise spotting rules for subtitling vertical video. 

By default, the subtitling and spotting rules used by Limecraft  for creating subtitles are optimised for maximum readability on horizontal videos (16:9). Given that vertical video items are mostly used via social media on smartphones, you may want to apply a different style guide to improve readability.


A vertical video is a video created either by a camera or computer that is intended for viewing in portrait mode, producing an image that is taller than it is wide. Because of this tall image, you need to adjust the settings to ensure a good readability. You need to have less characters on one line and have more lines visible on the screen. 


We recommend creating a dedicated Subtitle Preset for vertical videos. Note that the cell resolution settings discussed below are only visible when you export subtitles in EBU-TT-D format. 


More on EBU-TT-D and other Subtitle File Formats


Below you find our recommendations for the subtitle preset settings for vertical video (aspect ratio 9/16). 


1. Regions


To begin, go to the production settings, subtitle editor and create a new subtitle preset for vertical videos. 


Preview Aspect Ratio


The black box that you can see in the Region Configuration settings is your preview window. Change the aspect ratio of the preview in the lower right corner of the box. 





Region settings


Adapt the region settings to determine where on the screen your subtitles are shown. 


There you’ll see “Bottom Region” and “Top Region”. We recommend using, 80% width and 13-15% height (for both) and to try if these fit your content. You can drag the Bottom region and top region position to a desired position in the preview window. 



 

2. Cell resolution


In the Layout section, you will find the cell resolution settings.




The cell resolution defines a virtual 2D grid of cells over the video canvas. “Cell Resolution X” defines the number of columns in this grid, and Cell Resolution Y defines the number of rows in this grid. As font size and line height are based on the cell height, cell Resolution Y can be used to influence the subtitle font size. A more thorough explanation can be found here: 

https://www.bbc.co.uk/accessibility/forproducts/guides/subtitles/#ttp-cellResolution


For a vertical video, we recommend changing the cell resolution to X 25 and Y 37. 



3. Characters on a line and number of lines


Lower on the page, you will find the Automatic Subtitler Spotting Rules section. 


It is recommended to change the Character limits according to below:


  • The amount of characters on a line: at most 25 characters (hard limit 29 characters)

  • The number of lines: 3 lines (hard limit 4 lines)