Subtitle cannot be written if too far into negatives

[epistularum]

If for whatever reason you need to retime a subtitle file far away into the negative values then it becomes impossible to be saved and the plugin seemingly crashes.

Perhaps any line with a timing below zero needs to be scrapped?

concrete example:
I downloaded a subtitle file for a set of three 40min movies but the subtitle files bundles all the movies into one whilst the downloaded source material is cut into three files for each movies. I was able to save the file for the second movie when going 40min or so in the negative values but the subtitle for the third movie cannot be saved. Perhaps it's because it goes over the -60min line?