Developers working on the web's most heavily trafficked sites cite WebVTT's inconsistent behavior across browsers as a major reason for their choice to not use it in favor of other subtitlting/captioning options. This is unfortunate for several reasons. First, web standards should be reliable and trustworthy. Second, the lack of a standard for text tracks used broadly across the web means browsers cannot effectively apply accessibility features to subtitles/captions for users who need them, which, to make matters worse, can be an FCC violation.
Fortunately, we have a WebVTT test suite that can help browsers figure out what they should fix. Chrome, Firefox, and Safari on average pass 53.6% of tests. If you look at just the rendering category, this average drops down to 12.9%, with no browser passing more than 77 out of 251. Unfortunately, with the many known and unknown issues in the WebVTT test suite, it is hard for browsers to determine from their test results what needs to change in their implementation.
The purpose of this investigation is to fix as many tests as we can, making any needed changes to WebVTT documentation along the way, so browser developers have a more transparent understanding of how their implementation conforms to the standard, hopefully opening up the future possibility for greatly improved interopability.
Anyone! As for now, you can contribute by joining our first meeting on Wednesday, July 23, 2025.
More information to come!!!