For all of you people that love aegisub because it still is the best subtitle program, but need to have their workflow output to ttml.
This is still a WIP, coded initially to the netflix spec available here: https://backlothelp.netflix.com/hc/en-us/articles/215758617-Timed-Text-Style-Guide-General-Requirements
usage
gass2ttml <input.ass> <output.xml>
setting output is optional. run gass2ttml -h for other options.
build using go build