Bitmap subtitles with non-text content,converting PNG+BDN/XML/TTML2 to PGS/VobSub/SUP

[zn]

Is it possible to use graphical subtitles for non-textual visual information, to display simple graphics (series of png images, that I can turn on and off during playback)?
How I can encode series of png files into graphical subtitles?

[LowDead]

Try easySUP

https://forum.doom9.org/showthread.php?t=149160

//LD

[zn]

easySUP use text input, but I want to use non-text graphics (png images) for input, like this:
PNG files to BDN (XML+PNG) or TTML2+PNG (or IDX+SUB or PGS or SUP ?)

So, it looks like I need do these steps:

1) make BDN XML file using avs2bdnxml (or manually make XML in text editor)
146493

2) import PNG+BDN XML to BDSup2Sub
145277

3) export to VobSub(SUB+IDX) and/or Blu-Ray-SUP (PGS) from BDSup2Sub

4) mux it to mkv using mkvmerge (PGS and VobSub support listed)
https://mkvtoolnix.download/doc/mkvmerge.html#mkvmerge.subtitles

[LowDead]

Well, the only other I know of is SupConverter (http://www.defsoft.com/supconverter.html) but I don't know if you must have the Pro version and that costs $199. The LE version is free.