A VTT file, also known as WebVTT or a "Web Video Text Track" file, is a commonly used caption and subtitle format with the .vtt extension. The WHATWG (Web Hypertext Application Technology Working Group) developed it back in 2010 as a standard to support text tracks in HTML5 content and replace WebSRT (Web Subtitle Resource Tracks).
All You Need to Know About VTT Files
The WebVTT files are mainly based on the more popular SubRip format. This variation was even called WebSRT for a while and had the same .srt extension, but it was renamed to WebVTT later and got a tag for HTML. This format can include additional information about online video, including captions, subtitles, additional descriptions, metadata, and chapter information for easier navigation.
Most video platforms like YouTube, Brightcove, and Vimeo allow content creators to add their subtitles or captions from .vtt files. These files are also compatible with popular media players like VLC and GOM Player. While they're primarily associated with Google Chrome, they work just as well with any popular web browser.
How Are VTT Files Different From SRT?
Just like .srt, the .vtt files are text files that contain video subtitles or captions formatted in the WebVTT standard for displaying timed text. The format is very similar to .srt, with a few key differences.
Unlike SubRip, WebVTT supports the inclusion of descriptions and metadata within the frames - this data is not visible to the viewer.
All .srt files start with a "1" to mark the first caption sequence, while every WebVTT file starts with "WebVTT".
Cue identifiers are used to separate the frames in .srt files, but they're optional for .vtt.
Timestamps are separated by commas in .srt files and full stops in .vtt.
UTF-8 encoding is a requirement for .vtt files and optional for .srt files.
Unlike .srt files, .vtt files can support supplemental information like frame placement.
What Does the WebVTT File Structure Look Like?
These files have two strict requirements ("WebVTT" at the beginning of the file and an empty line between every caption to mark the end of a sequence) and several optional components:
The byte order mark (or BOM) "EF BB BF" (from 0xEF,0xBB,0xBF sequence) to indicate the file is encoded with UTF-8.
A header next to the "WebVTT" in the first line, separated with a space, to describe the file as necessary.
Comments on separate lines starting with "NOTE", separated from other sequences by an empty line.
Caption placement information in the same line after the second timecode.
Each line that contains captions or subtitles starts with a time code. The format used depends on the video length - minutes:seconds.milliseconds or hours:minutes:seconds.milliseconds. The milliseconds are rounded to three decimal places, and an arrow (-->) separates the captions in each line. Let's have a closer look at an example.
WebVTT - You can place your comment here
This is also a comment that spans across two lines.
The next line has a cue setting example.
00:00:00.000 --> 00:00:05.500 position:90% align:left size:20%
Where did he go?
00:00:07:000 --> 00:00:09:200
I think he went down that way.
00:00:11:100 --> 00:00:13:400
Well, what are we waiting for?
How to Edit VTT Files?
You can view and edit .vtt files using pretty much any text editor such as Microsoft's Notepad, Apple's TextEdit, or a cross-platform option like Atom or Sublime. Also, if you load a .vtt file in a browser, you'll be able to view its contents. If you're wondering how to open .vtt files and use them as a subtitle track in VLC or a similar player, all you need to do is drag the file and drop it into the player's window.
How to Create VTT Files?
When it comes to creating .vtt files, you have three options - you can make one yourself, convert a different format into a .vtt file, or use a professional captioning service like GoTranscript. If you don't have time to figure out the formatting, positioning, and other features this format offers, outsourcing to a professional company is a great option.
Are There Any Downsides to Creating Your Own VTT Files?
As mentioned above, creating your own caption files is free. If you have some experience, it's also fairly easy. However, if you're not familiar with timecodes and all the style elements the format offers, it can be a time-consuming process. You'll save some money if you decide to do it yourself, but you'll lose time getting familiar with the ins and outs of WebVTT's formatting style and rules.
The time required to create captions depends on video length, audio quality, and your experience. A five-minute video can take five to six times the video's length to complete, even for a seasoned transcriptionist. If you plan to create your own timecodes, cue settings, and use other features of the WebVTT format, this will take significantly longer.
There are many benefits to using captions, from SEO improvements to reaching new audiences and making your videos more accessible for deaf and hard-of-hearing individuals. While creating your own captions is definitely viable, it can take quite a bit of time, especially if you have lots of video content to go through.
With a professional captioning service, there's no need to worry about formatting, accuracy, and compliance. A company like GoTranscript can take care of your captioning needs with 99% (or higher) accuracy with quick turnaround times and pricing for every budget.