Debugging VTT files (Captions & chapters)

If you ever have an issue with a caption of chapter (both use VTT files), here’s the primary tool I use to troubleshoot:

  • webVTT validator.- If the code looks good, it’ll tell you! And it is really good and finding persnickety things that are tough for the human eye to find.

As an example, a customer was having trouble having their final chapter appear in their list:

00:43:14:000 --> 00:54:11:000
Henry VIII: Second verse, same as the first

Everything seems ok, but the validator gives away the issue:

Almost there! (0ms)

Line 32, column 9: No decimal separator (".") found.

Between seconds and milliseconds, we need to replace the “:” with “.”, as sshown below:

00:43:14.000 --> 00:54:11.000
Henry VIII: Second verse, same as the first

and the chapter appeared as we expected.