[mythtv-users] Myth, ivtv, and VBI. Is it possible?

Bryan Lockwood bryan at lockwoods.us
Fri May 27 17:51:50 UTC 2005

You could try getting the latest 3.x ivtv drivers, then fool around with the
ivtvctl (on my Ubuntu system it is at /usr/src/ivtv-0.3.4u/utils/ivtvctl)

Relevant arguments for ivtvctl:

  -b, --set-vbi=<mode>   sets the VBI mode. 
        <mode> is a comma separated list of:
                     raw: raw VBI mode
                     teletext: sliced teletext
                     cc: sliced closed caption
                     wss: sliced widescreen signal
                     vps: sliced vps
  -B, --get-vbi      gets the VBI mode.
  -w, --set-vbi-passthrough=<mode>
                     sets the VBI passthrough mode
                     <mode> is a comma separated list of:
                     none: no passthrough
                     cc: closed caption
                     wss: widescreen signal
                     vps: vps
  -W, --get-vbi-passthrough
                     gets the VBI passthrough mode
  -x, --set-vbi-embed=<mode>
                     sets whether VBI data is embedded in the MPEG stream.
                     if 1, embed VBI data in the MPEG stream, if 0, don't.
  -X, --get-vbi-embed
                     gets whether VBI data is embedded in the MPEG stream.

At the moment I don't know which of these options MythTV expects. I'd try
this first:

ivtvctl -b raw -x 1

... then toggle CC within MythTV. I've tried every combination of these
options on my PVR250 using ivtv version 0.3.4u. No joy. But rumor has it the
PVR350 may work better.

You can verify whether your PVR 350 is passing CC info to ivtv by tuning
Myth to a channel where you know CC data is. Then exit live TV, and at a
command prompt, run /usr/src/ivtv-0.3.4u/utils/vbi. After a minute or two
you should see the CC text.

Please let us know what you find out, including whatever version of ivtv
you're running. I'm trying to build a list of what works and what doesn't so
future Myth users won't share out pain!


-----Original Message-----
From: Greg Chila [mailto:greg.chila at gmail.com] 
Sent: Friday, May 27, 2005 8:10 AM
To: mythtv-users at mythtv.org
Subject: [mythtv-users] Myth, ivtv, and VBI. Is it possible?

I've been a mythTV user for almost two years now, and never looked
back.  However, I just built a mythbox for my girlfriend.  Everything
is working great (audio is a little off, but otherwise OK).  The
problem is, she loves closed captioning.

I know myth has support for CC (aka VBI), and I have the options
enabled in myth's setup, but I cannot figure out how to properly
configure the pvr250MCE so that CC will work.  The pvr350 in my box
also won't work.  I've scoured the net trying to find a solution, but
none is available.

Can someone point me in the right direction to enable VBI?  I've seen
some inferences in the ivtv mailing list that embedding VBI in the
mpeg stream has been possible for some time, but no details on how
this is possible.  Is this how myth expects the VBI, embedded in the

*Any* help at all is much appreciated.

Greg Chila

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