Dear all,
I am currently trying to convert a series of M2TS files to one MKV file using external timestamp files. In the resulting file, there are no problems with the audio and video tracks, but a issue with the subtitle track:
The first subtitle is not removed (“undisplayed”) at the expected time; it should last about two seconds, but in fact is displayed for minutes until the next subtitle replaces it. I have double checked that the second timestamp in the external subtitle timestamp file designates the time when the first subtitle should disappear. I also have verified that the value of this second timestamp is correct (I’ve used BDSup2Sub++ and SubtitleEdit for this verification).
The other subtitles (there are 489 of them) are working correctly; the issue is only with the first subtitle. Furthermore, if I let mkvmerge create the MKV file from the M2TS files without external timestamp files, the issue does not exist.
Could the problem be due to a bug (I guess that it’s only a few people who use external timestamp files with subtitles)? Or are there special requirements for the first subtitle in a subtitle track? Does the PTS of subtitles (display or “undisplay”) need to coincide with the PTS of a video frame?
Thank you very much in advance, and best regards!
P.S. If necessary, I could upload the first part of the M2TS file in question somewhere (along with the timestamp file) and send the link via PM to interested parties. The M2TS file is about 15 GB, but the problematic (first) subtitle is at second 42, so I guess it would be sufficient to upload the first 200 MB.