1
00:00:00,500 --> 00:00:02,500
Start with your original MP4.

2
00:00:03,000 --> 00:00:05,500
Add an existing UTF-8 SRT file.

3
00:00:06,000 --> 00:00:08,500
Keep captions selectable when supported.

4
00:00:09,000 --> 00:00:11,500
Check timing before sharing.