Subtitle entries overlap after stretching because of different rounding
I'm stretching these subtitles with the fraction 24000/25025. This:
6 00:00:00,500 --> 00:00:00,600 . 7 00:00:00,600 --> 00:00:00,700
Becomes this after stretching:
6 00:00:00,480 --> 00:00:00,576 . 7 00:00:00,575 --> 00:00:00,671
600*(24000/25025) = 575.4245754245754
When it's an ending timestamp, 575.4 is rounded to 576, but when it's a beginning timestamp, 575.4 is rounded to 575. Which is a problem, because now the subtitle entries overlap, and in the original file they didn't. This could lead to visible differences in playback (not just a different speed).
A workaround would be to stretch the subtitles with a specialized subtitles editor, changing the framerate of the subtitles from 23.976 to 25. But probably many people are unaware that the "Stretch by" option for subtitles in mkvmerge could lead to overlapping, causing playback issues in some players.