Web Captions 1B – Additional Caption Formats

Entry categories Accessibility
Japanese calligraphy on rice paper. Photo by Raychan on Unsplash

Last time in this Web Captions series, I covered two of the primary formats for creating captions on videos. And foolishly, I assumed there were only two. I was wrong.

The File Type Landscape

I’ve since discovered there are additional caption formats that use fifty plus file types, with various standards within each! For example, there are a few different formats that use the TXT file type as their wrapper. Most of these seem to work specifically with one-off apps you’ve never likely heard of.

However, there is another file format called SRT that is almost identical to VTT. It’s a tad simpler to write, it seems, but it’s not as robust. It is an accepted format for some major services, but like TTML, it doesn’t work natively in the HTML video tag the way that VTT files do. If you’d like a more in-depth overview, check out this article by JBI Studios.

Managing the Mess

I’m so thankful that the W3C did the right thing, and forced a single, robust, easy-to-write format and that all major browsers complied. What a mess it would have been if they didn’t.

So what do you do if you receive a non-VTT file as your caption content? Thankfully, this time around, I have a better answer as to what tooling to use. Subtitle Edit is a free, actively-developed, Windows-only application with a portable installer (which I now keep on my cloud sync service).

Subtitle Edit's interface showing the timestamped caption content and video preview. It also handles additional caption formats

On a quick exploration, this application is serious business. It converts about seventy plus formats to other additional caption formats, including the critical VTT needed to caption media natively on the web. It can help you translate content, it has plugins for localizing US English to UK English, and it tracks how many words appear per second of on-screen display (extremely critical, which we will get to in the next part of the series).

Conclusion (again)

The world of captions is so much deeper than I first suspected. I hope that I’ve made your life just a little easier as you dive into this strange but critical corner of design, usability, and accessibility.

In the next part, I’ll be diving into design principles some key industries have published.