[Sybren Arnoldus]

.. seems like creativecow didn’t post my reply .. here is the short version:

For your situation, use Andrea’s X-Title Extractor. Works very well and saves you a ton of time.
– make a new FCPX project and paste all your subs in there.
– export the xml of this project
– open X-title Extractor and bring the xml file in there
– export the srt
– if needed, convert the srt to ttml with the online tool

Andreas did a great job on the X-title tools, don’t forget to make a donation. Also to get rid of the 50 subs limitation.
Kolibri is only for subtitling outside FCPX.

[Sybren Arnoldus]

Hi Javier, look here: https://gotranscript.com/subtitle-converter super easy!

About Kolibri, I like it but the last update was 2013. My guess is it won’t be updated so some day it will stop working. A bit of a gamble to buy it but not a huge loss if it stops working. Somebody should buy the source code and continue the development …
And as Andreas pointed out, Kolibri does not import / export to FCPX.

[Sybren Arnoldus]

Just to add my subtitling experience to the discussion. I use ‘Kolibri’ to make the subtitles. Kolibri is a standalone app and works a bit like those expensive professional subtitling solutions. It’s not perfect and needs an update but it’s quick. It’s about $40 in the App Store. Kolibri exports to a few subtitle formats, ready for youtube, vimeo etcetera. Unfortunately not ttml but you could use an online converter.

To burn the subs you can use SugarFX but imo it’s too expensive. Digital Heaven SubtitleX with X-importer do the trick as well.