[FFmpeg-user] pgssub direct to .sub & .idx ? Possible?

[Marth64]

SubtitleEdit can process PGS streams directly in a Matroska container.
By converting to DVD sub you are reducing their quality which may
make OCR more difficult if that is of value to you.

My personal convention for dealing with these is to isolate
and streamcopy them to Matroska with .mks extension, and
with -cues_to_front 1 on the Matroska muxer (this flag more crucial if
muxing them with video and audio as well, or SE will struggle with the file).

SubtitleEdit will happily accept the files and process them quickly.

TLDR:

```
ffmpeg -i MySegment.m2ts -map 0:s:0 -c:s copy -f matroska
-cues_to_front 1 MySubtitles.mks
```