Re: Capturing Closed Caption Bitmaps

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

From: Peter Feldbaumer (nobody_at_nowhere.in.the.net)
Date: 02/25/04 

Date: Wed, 25 Feb 2004 15:01:08 +0100

EK wrote:
> I'm trying to capture the close captions from a DVD connected to my pc
> using a WinTV card.
>
> The initial part of identifying and selecting the card input (S-Video)
> and connecting the VBI are accomplished and currently the movie is
> playing (with subtitles).

This isn't going to work at all!!!

What you're doing here is to capture the image your dvd-player is
generating - nothing more is (and can be done) on the PC-side!
However your dvd-player is inserting cc (images/overlays/texts) onto the
video-output it generates (so note: your dvd-player "mixes" the dvd-video
and the cc-contents!). The dvd-player does NOT output some kind of
CC-"substream" (like tv-channels do) which can be decoded/captured
seperately from the video by your PC!

> My problem is as follows:
> Since I can't find a way to get the text/string directly I was
> thinking of capturing the close captions to bitmaps file and then
> using some OCR component extract the text strings.

See above - you can only capture the region of the screen which contains the
CCs (but only including the video behind it!). So all DShow-Components
related to CCs are completely useless for you - they can only be used
together with TV-broadcast!

> If there is a way to directly capture the close captions as text
> string I would love to know about, if not, capturing the close
> captions to bit maps files will do the job.

Use a PC-(software) DVD-Player (so no external dvd-player!) - this way you
can capture the CC-stream from a DVD via DShow (the dvd-decoder-filter will
have a cc-output-pin, which only contains the "sub-images/titles") 

-- 
Peter Feldbaumer
p dot feldbaumer at utanet dot at

Relevant Pages

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