Date: Mon, 12 Dec 2005 23:17:51 +0100
From: Hans Verkuil <[EMAIL PROTECTED]>
On Monday 12 December 2005 21:51, Geoffrey Kruse wrote:
> Are there any plans to include embedding the closed captions on these
> cards or is it not physically possible? Currently, this is the only
> form of VBI that mythtv will support.
Yes, it is possible, I just don't know how. Embedded VBI support works
for PAL, but I cannot get it to work for NTSC. Lack of time prevents me
from continuing my attempts at making it work. A ticket has been
created for this problem.
Am I misunderstanding something about what "embedded" means? I've
been using ivtv 0.4.1 to capture closed-captioning data for the last
several days, using NTSC (I'm in the US) and Myth 0.18.1, and it's
been working fine. (Myth -itself- has no idea what to make of it,
but the -350's output redisplays it, and I've been working w/some
tools that can parse the text out of the resulting mpeg2; I've
posted about 'em to the various lists a bit in the last week.)
Or do you mean "taking closed captions from some other non-x50 source
and putting it -back- into the stream so a -350 can display it"?
I'm probably going to be playing around with CC a fair bit once I
finish configuring the boxes I've been setting up (e.g., at least
a couple weeks from now), though one problem is deciding whether to
spring for the actual standards and/or books about them, which are
expensive, so once I figure out what you're trying to do, I might
be able to lend a hand.
(Speaking of which, does anyone reading this have copies of either
_The Closed Captioning Handbook_ by Gary Robson (described at [1]
along with other useful stuff that unfortunately does -not- include
actual bits (since he's shilling for his book) at [2], or copies of
the actual standards (which are pricey and for which it's unclear
exactly which one defines packet headers & bit fields)? I'm currently
trying to figure out what defines the difference between CC1 and TEXT2
packet data in line 21, and am probably going to have to go look at
the raw bytestream and see if I can detect the difference; if someone
already knows this or has access to relevant standards documents, it
could save me some work. So far, interlibrary loan hasn't been too
helpful in this regard. Tnx!)
[1] http://captinoing.robson.org/handbook/
[2] http://captioning.robson.org/articles/general/nv-line21.html
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