Function or filter to aid Subrip OCR?

[kai0n7]

I've run into a video I was trying to extract subtitles from that is proving to be very difficult... the color of the text tends to be the same as the content it was encoded over except for the outline, and Subrip is puking all over.

Is there a function or filter that can possibly help Subrip get a better fix on text, some kind of masking maybe?

[kastiauto]

Hi

I got same problem. I'm using this method http://zuggy.wz.cz/guides/video.htm

Here is screen from video
http://i43.tinypic.com/13zqvqs.png
And sample
http://web.zone.ee/trepp/headkaed.ts (~7MB)

As You can see there is half sub's on the video. I would like to blur/"hide"/darken the background or recolor subtitles so Subrip can recognize these better.
__

Actually the problem is with frames no subtitles on it. Subrip then detects random white/light pixels. If i can use some "autoadd borders" which covers video when there is no subtitles on, then it would be much easier to rip.