Here and
here I found some documentations.
In my
previous post is a link for DVB Subtitles (as bitmap) which can be viewed by VLC and
here seems to be a file with both types of subtitles (teletext and bitmaps) as reported and viewed by VLC. I think for MPEG2 only teletext subtitles are used, but for H264 can be used both types.
ProjectX can extract the DVB Subtitles but sometimes the palette of idx is wrong and the SUP file saved is SD not HD.
I saw in some eac3to log that the program can detect the DVB Subtitles correct even it cannot export them.
In my two provided samples the subtitles are detected as AAC or AC3.
enjoy,
Mtz