In youtube there are videos which includes texts. For example,. This video consists of texts, I was wondering if it is possible to get all those texts into a doc or text file. Is there any such program or online service available?
Automated text extraction from video is still an emerging technology.
Another option is an open source proof of concept from a research paper, LOOV. You will need to compile this from source.
This post describes a workflow for automatically extracting screenshots to stills and then running OCR on the stills. You could probably adapt this workflow to other tools besides what are described in the post.
You might want to look up "OCR" which stands for Optical Character Recognition. There are many programs that can do it from a still frame. At worst, you could choose specific frames from your movie to pass to such an application.