SOLVED: Issues with subtitle syncing

[TheDreadPirate]

Since SRT subs are directly sent to the client, a lot of the work is done by the client so it is partially/entirely up to how each client handles displaying SRT subs. From my own testing it seems that Firefox loses sync the most easily.

Some preliminary tests I did a while ago, but forgot to follow up on, was that remuxing the video with this command APPEARED to resolve the issue.

Code:

ffmpeg -fflags +genpts+igndts -i "/path/to/video.mkv" -codec copy -max_muxing_queue_size 2048 -max_interleave_delta 0 newFile.mkv

Even though the SRT subs were external in my case, it appeared that the +genpts+igndts options resolved any subtitle desync issue on the test video I had.