How to edit .sub/.idx ?

[Mokuton]

A screenshot from the 1080p video;



I want to change the fonts, size, colour and the location of this subtitle and merge it back to the mkv with mkvmerge GUI.

I extracted the subtitle with MKVExtractGUI 1.6.4.1 but can't open it with Aegisub or Subtitle Workshop. I get errors like "Unknown file type"

These are the files i get after the extraction and am unable to open;
http://mokuton.com/images/videohelp/Spirited%20Away%202001%20HDTV%201080p_Track3.sub
http://mokuton.com/images/videohelp/Spirited%20Away%202001%20HDTV%201080p_Track3.idx
http://mokuton.com/images/videohelp/Spirited%20Away%202001%20HDTV%201080p_Chapters.txt

(Online virus scanner for downloaders without antivirus : http://virusscan.jotti.org/en )

So what do you guys think? How can i edit this subtitle?

[Baldrick]

Convert to text subtitles with subtitle edit.

[Mokuton]

I think it's impossible :C

[manono]

You can change the colors and location/position of VobSubs without an OCR. To change the font and size you have to perform a full OCR as mentioned above by Baldrick. I have them for an NTSC version of Spirited Away in SSA format. SSA subs are easy to edit for font/size/position/color, etc. I'll upload them.