PGS subtitles- The .sup file extension stands for subtitle bitmap image extracted from a Blu-ray movie; it contains subtitle text graphics that are displayed during movie playback. The .sup subtitles are encoded with PGS codec, and sometimes known as PGS subtitles. Blu-ray PGS subtitles is not so widely supported by HD media players as DVD subtitles(learn which HD player support PGS subtitles) and usually need to be converted to more common subtitle format like SRT, SSA, IDX, ASS, etc. When a Blu-ray is ripped into .m2ts streams, the .sup subtitles can be extracted by demuxing the M2TS using tsMuxer (guide).
SRT subtitles- The .srt is primarily associated to DivX, DVD and some other video formats (e.g. MKV) as external subtitle format. SRT files are text files used in video playback. Therefore, they do not contain any video data, but they include the time each subtitle should be displayed followed by the text of the subtitle.
Guide- Converting PGS .sup subtitles to .srt using SupRip (FREE TOOL).
SupRip v1.16 Download (Windows ONLY, Mac users you can have a try with this app if you’re ripping Blu-ray to Mac, which lets you convert Blu-ray .sup subtitles straightly from Blu-ray Disc)
1. Start SupRip, load the SUP file with the “Open” button.
2. Click “Auto-OCR” to automatically scan the whole file and leave any unknown characters alone.
3. Go to the SRT tab
4. Review the subtitles and statistics. Change some options there if you want.
5. Save the SRT file with the “Save” button
How to name multiple srt files so that the language shows to select:
1) name the subtitles exactly as the video stream. E.g. 00033.m2ts-> 00033.srt
2) give an id to subtitles with different languages. E.g. name English subtitles xxx.en.srt and German subtitles xxx.de.srt
What’s annoying- there are lots of spelling mistakes and indistinguishable characters when Auto-OCR is used, and you have to proof and correct them one by one.