stitching subtitle stream onto avi

Hi,

I understand that the usual way to handle subtitles is to get subtitle 
preview images
and then "gocr" them to get subtitle text. But I'm finding that gocr 
isn't quite upto the mark.

I also notice that when you extract the subtitle stream for a dvd video, 
it comes to around 5-6 MB. So I was wondering if there's a way we can 
just stitch this raw subtitle stream as it is onto the encoded avi file, 
rather than fiddle with gocr and convert the stream to text.

(I mean like stitching the raw ac3 audio stream back onto the encoded 
video and avoiding processing the audio altogether)

/v