Subtitles file formats: The most used and when choose each one

Do you want to add subtitles to your videos and don't know which format is better or which one to choose?

The existence of so many different subtitle file formats makes it difficult to decide, so I offer you a list of the main types of subtitle files and their characteristics.

In addition to the list, I will tell you about another possibility, which makes it easy to place subtitles quickly, accurately and with other advantages so that you can choose the best option for subtitling your videos.

What are the most common subtitle file formats?

Here I will tell you about the most commonly used subtitle file formats and their main features.

 1. SRT

SRT file is one of the most popular subtitle file formats for video content. They are plain text files and include the subtitle text in sequence and start and end timecodes.

They do not contain video or audio, so they are small. They allow creation of more inclusive content for people with hearing difficulties and those who like to read text on the screen.

Everyone appreciates videos with SRT subtitles, as they are accessible, increase reach and benefit the video's SEO. Your content will get more views and likes than ever.

2. VTT

VTT is used on web pages, and many video platforms, such as YouTube, display subtitles in streaming videos.

It is based on SRT but has additional options, such as the ability to customize the caption font style, sizes, colours, position, and alignment and can include multiple languages.

subtitles file formats


This type of subtitle file is prevalent among broadcast channels and VOD services. It allows you to encode subtitles, although it has many rules regarding the number of characters, colours and positions that can be customized.

It adapts to various video formats, and the BBC and many other TV channels use the modern version of STL. Without the limitations of SRT, it is the most appropriate subtitle format for broadcast companies and professionals.

 4. SSA

SSA, or Substation Alpha, is more advanced than SRT and allows you to control many text parameters: font formatting, colour, height, transparency and placement.

It is pretty popular and widely used by anime fans to create subtitles. Its more advanced version, ASS, has even more specific graphic and text features and allows you to make animated subtitles and lyrics for karaoke videos.

 5. TTML

Timed Text Markup Language (TTML) is a technical format widely used by the television, broadcast and VOD industry.

It stands out for being customizable, which is why it is ideal for encoding and transposing text data into live video and audio streams.

6. SUB

This format is widely used. Its difference with SRT is that the linking is done by frame number and not by time; this makes it less reliable.

If the frame rate of the movie copy and the one for which the subtitles were made do not match, the synchronization will be lost.

This type of subtitle file is straightforward and offers no additional configuration options or support for advanced text effects.

7. SMI

This is an official Microsoft format; it is flexible and well-documented. However, finding a good converter for this file type is challenging.

Its structure is reminiscent of an HTML document and is the only format the standard Windows Media Player can play.

8. TXT

The TXT is a plain text file with which you can create video dialogues, but it will not work for most players. To do this, you have to organize them according to a precise encoding, which takes time.

Most video players and software support more universal formats, such as SRT and VTT, which are more optimal than TXT.

Which file format to choose for my projects?

SRT and VTT file formats are the simplest and most common; they work with most video players and are the most commonly used on social networking sites.

Here is the sequence for creating subtitles in SRT format (the hard way):

  1. Open a plain text editor, such as Notepad.
  2. Label each line of subtitles, starting with the number 1.
  3. Insert the time code to indicate how long the text should remain on the screen.
  4. Type the text you want

Repeat steps 2 to 4 until the video content is complete. When saving the file, choose between the SRT subtitle file extensions in the "Save As" option.

Once you click "Save", the SRT subtitles are ready to be loaded. This is the manual way to do it, it takes a lot of time, and any mistake can discard the whole subtitle sequence.

Can I get subtitles automatically in the format of my choice? (Easy way)

Yes, with ScriptMe's automatic subtitle generator.

Just upload the files, and in moments, video subtitles are created or can be burned into the video itself. You can custom-style them and translate them into more than 100 languages.

Using the editor is very easy to customize subtitles to perfection: you can trim and design subtitles and choose colour, font and backgrounds ideal for all your projects.

Subtitles can be exported in SRT or VTT format; share the link to your project and receive support to improve subtitling.

subtitle file extensions


Among the subtitle formats, SRT and VTT stand out; they are the most used because they are compatible with the leading platforms, multimedia players and Windows media players.

Performing subtitling with the subtitle file types requires a lot of time and attention; an option to do it faster and more accurately is with the automatic subtitle generator.

You can contact ScriptMe, and we will happily provide you with all the information. Whatever your decision is, we hope we have been helpful and wish you success in creating subtitles for your videos.

Emil Nikkhah
Hi, I'm Emil Nikkhah.
For over 25 years, I have successfully built several television post-production companies.
Frustrated by the high cost and slowness of manual transcription and subtitling in this industry, we decided to create ScriptMe, a powerful software for automatic transcription and subtitling.
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