Closed Captioning: from a DVD to a String

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Guest

Hello all!
I'm trying (read: becoming frustrated) to write a DVD viewer in VB.NET. I
can embed the DVD picture using DirectX technology, but it seems to be
impossible to obtain closed captioning from the DVD and convert it to a
string. There were a few tips on getting the captioning in the MSDN, I know,
but they were rather cryptic (unusual) and didn't convert the captioning to a
string.
If there is anyone who can help me, or even just tell me what I'm trying is
impossible, I'd be most grateful.
 
Wraith said:
Hello all!
I'm trying (read: becoming frustrated) to write a DVD viewer in VB.NET. I
can embed the DVD picture using DirectX technology, but it seems to be
impossible to obtain closed captioning from the DVD and convert it to a
string. There were a few tips on getting the captioning in the MSDN, I know,
but they were rather cryptic (unusual) and didn't convert the captioning to a
string.
If there is anyone who can help me, or even just tell me what I'm trying is
impossible, I'd be most grateful.
Click to expand...

I assume you mean subtitles? They aren't stored in text. They're
actually bitmaps/movies. There are some releases that particular feature
for some nice extra effects where the shadow of the director for
instance draws stuff on the screen.

If you want the subs in plain text you'll have to extract the subtitle
stream and OCR it.
 
Rinze, thanks for your response. I had heard that subtitles were images, but
most DVDs also carry the old closed captioning as well. I know this because I
have a filter on my television that works by reading the captioning, and it
works equally well with DVDs. However, I do not know whether or not this
captioning is able to be decrypted or not.
Anybody have any suggestions?
 
Wraith said:
Rinze, thanks for your response. I had heard that subtitles were images, but
most DVDs also carry the old closed captioning as well. I know this because I
have a filter on my television that works by reading the captioning, and it
works equally well with DVDs. However, I do not know whether or not this
captioning is able to be decrypted or not.
Anybody have any suggestions?
Click to expand...

After your comments I did some research and understand de difference
between CC and subs now. I found out CC is encoded on line 21 of the TV
signal. This may give you a starting point:
http://robson.org/capfaq/technical.html
Looks to me you have to actively scan line 21 of the picture and then
somehow decode the CC commands from there. How that is done, I have no
idea, I haven't found a webpage that describes that process.
 
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