Losing subs when S&L content overlaps dialogue

[mwalimu]

I've encountered an issue where some subtitles get lost when dialogue content overlaps S&L content (signs and lyrics, also including any other onscreen writing). Here's what I know so far.

All subs appear when playing the Blu-ray.
All subs appear when playing the ripped/decrypted file in VLC.
Using tsMuxeR if I extract from the playlist to Blu-ray folder and play the resulting 00000.m2ts in VLC, all subs appear.
Using tsMuxeR if I extract from the playlist and use Demux to extract only the PGS file, then view the resulting .sup file in BDSup2Sub, the overlapping content is missing.
Using RibBot264 if I create a job using the 00000.m2ts file in the Blu-ray folder that tsMuxeR created, then view the resulting .sup file in the jobx folder using BDSup2Sub, the overlapping content is missing. In the same jobx folder, the file 'video-log.txt' shows that it ran eac3to under the covers, and the eac3to output includes a line that says 'Subtitle track y includes nnn captions.'. In one particular example, nnn was 466 but the resulting .sup file has only 440 captions according to BDSup2Sub. That difference of 26 captions reasonably matches the lost overlapping content.
Of course the lost overlapping content is still missing from the converted .sub/.idx files, and the final output from RipBot264.

Edit: It turns out both both txMuxeR and eac3to were demuxing correctly and the problem was with BDSup2Sub losing captions when it loaded the .sup file.

Is there a tool I can use to extract subtitles from the .m2ts source material that retains all of the overlapping captions intact to the .sup file (or at least to the subsequent .sub/.idx files), i.e. in the example above all 466 captions instead of just 440?

[Nikse]

You could try Subtitle Edit. Tools - Batch convert, choose .m2ts files and "Blu-ray sup" as target format (almost bottom of the format list).
Does that work for you?

[mwalimu]

You could try Subtitle Edit. Tools - Batch convert, choose .m2ts files and "Blu-ray sup" as target format (almost bottom of the format list).
Does that work for you?

Thanks for the tip. I've done a little experimenting with it on the same example file referred to in the original post, and so far the results are not very good. Trying to use batch convert as you suggested on the original .m2ts file lost about 3/4ths of the subs, but when I tried it on a copy of an .mkv file with the same PGS subtitle track, it returned 428 subtitle frames (captions). That's still not very good, as it's less than the 440 I was getting from tsMuxeR and eac3to (and I've already established that even with 440 some frames have already been lost). (By the way, I also tried VobSub as the target format and got essentially the same results.)

My impression of Subtitle Edit is that it's heavily geared toward OCRing and performing text editing on subtitles, whereas PGS, .sup, and VobSub are all image based formats. At this point I'm not very optimistic that it will be helpful for what I'm trying to achieve.

[mwalimu]

Upon further investigation, I've determined that the .sup files produced by tsMuxer and eac3to (and ffmpeg, which I didn't mention but also tried), do in fact have all of the captions. The problem, as it turns out, is that BDSup2Sub wasn't loading all of them, and was losing captions in situations where Forced/S&L content overlapped dialogue content. (I also had an older version of BDSup2Sub but upon upgrading to the most recent found that the problem still exists.) BDSup2Sub++1.0.2 however was able to load all of the subs.