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mjl
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 Posted: Tue Dec 06, 2005 10:24 pm |
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Joined: Sun Jun 12, 2005 10:55 pm
Posts: 3161
Location:
Warwick, RI
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Hi,
What is the trick to make CC function? I have been unable to have CC display on a computer monitor or a tv. Is line 21 being passed?
I am using a PVR350 for the recordings and tv out.
Thanks
Mike
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Xsecrets
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Posted: Tue Dec 06, 2005 10:32 pm |
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Joined: Mon Oct 06, 2003 10:38 am
Posts: 4978
Location:
Nashville, TN
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do some searching on vbi that is what carries cc I don't know that it has been discussed much here, the ivtv mailing list is probably a better place to look.
_________________ Have a question search the forum and have a look at the KnoppMythWiki.
Xsecrets
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mjl
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Posted: Tue Dec 06, 2005 10:48 pm |
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Joined: Sun Jun 12, 2005 10:55 pm
Posts: 3161
Location:
Warwick, RI
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Hi Xsecrets,
I'll head over to ivtv for ideas. vbi (vertical blanking interval) does not carry CC. Line 21 is the first line of video and I would think be passed and recorded even if mythtv can't process it.
Not sure how it is handled in digital all though I can see the top line of smutz when in standard def.
Thanks
Mike
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Xsecrets
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Posted: Tue Dec 06, 2005 11:33 pm |
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Joined: Mon Oct 06, 2003 10:38 am
Posts: 4978
Location:
Nashville, TN
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well I've never played with cc, but I was told along time ago before the ivtv drivers supported the /dev/vbi? that vbi had to be implemented for cc, maybe I was misinformed.
_________________ Have a question search the forum and have a look at the KnoppMythWiki.
Xsecrets
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mjl
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Posted: Tue Dec 06, 2005 11:52 pm |
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Joined: Sun Jun 12, 2005 10:55 pm
Posts: 3161
Location:
Warwick, RI
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Hi Xsecrets,
There is a lot of stuff in the vbi area, it maybe that ivtv folks may have rolled first line of video into that because of it being digital. I'll let you know what & if I make any discoveries.
Thanks for the suggestions.
Have a great day!
Mike
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marc.aronson
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Posted: Tue Jan 03, 2006 11:54 am |
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Joined: Tue Jan 18, 2005 2:07 am
Posts: 1532
Location:
California
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Mike:
I've tried several times to get closed caption working, but I've never had any success. I'd also be very interested if you find a solution to this -- lack of CC on myth is the only reason I haven't gotten rid of my TIVO unit.
Based on some of the postings I've read, I believe that the player used by mythtv does look for CC data in the VBI...
Marc
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wififun
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Posted: Tue Jan 03, 2006 2:37 pm |
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Joined: Mon Jun 21, 2004 11:25 am
Posts: 291
Location:
Ontario, CA
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I have done a lot of playing with this to get CC working with the PVR x50 cards. My dad is nearly completely deaf and it is rather annoying that when he comes to my house he can't watch TV. For me this is one major flaw, that I have spent a lot of time trying to get to work, that just won't. We almost need to sign and interpret some content because he can't hear it. This is also the one thing preventing me from setting up a Myth box for my parents. The stability is within acceptable ranges, but without CC, it is a no go.
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marc.aronson
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Posted: Sat Jan 07, 2006 9:55 am |
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Joined: Tue Jan 18, 2005 2:07 am
Posts: 1532
Location:
California
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Mike, did you find anything else tha would help get closed caption working?
Marc
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mjl
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Posted: Sun Jan 08, 2006 12:43 am |
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Joined: Sun Jun 12, 2005 10:55 pm
Posts: 3161
Location:
Warwick, RI
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Hi Marc,
I haven't had to much of an oppertunity to look more closely at the CC however I suspect that part of the problem is the encoder is not starting capture until line 22. I plan to throw the 350 tv out put on a waveform monitor next week to confirm what I don't see.
I had diddled a little a while back as a curiousity and I just recalled that when I passed the video to a monitor that it did not decode the captioning. That in turned made me recall that I wasn't seeing the garbage at the top of the screen, ie, line 21 or the CC data. This would probably fall under the ivtv guys to allow the driver to pass that line. I have seen it on the digital, however I don't know if it works in a simular way or if it was because of upconversion of the analog signal.
There maybe some menu selection that I haven't tried either. Guess the next step would to go ask the ivtv group...
Now that the FCC has changed the CC rules (1st of Jan 06) it would be nice to have that working as a lot more stuff will be captioned.
Have a great day!
Mike
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marc.aronson
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Posted: Sun Jan 08, 2006 10:46 am |
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Joined: Tue Jan 18, 2005 2:07 am
Posts: 1532
Location:
California
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Mike, I did some digging in the IVTV "user" email archives and found a thread that sheds some light. The full thread is below, but I believe the summary is that you can set IVTV to capture closed-captioning in the mpeg2 stream, but myth won't play it back unless you are using a PVR-350 for playback. Also, they are using IVTV driver version 0.4.0 -- I believe Knoppmyth is packaged with 0.3.x. I'll post here if I find anything else.
Marc
Quote: On Friday 11 November 2005 12:33, Daniel A Segel wrote:
> Joseph A. Caputo wrote:
> > On Friday 11 November 2005 11:02, Daniel A Segel wrote:
> >
> >> rfluharty at 321online.net wrote:
> >>
> >>> I'm using a PVR-250 with ivtv 0.4.0 and 2.6.13 kernel. I mainly
> >>> use
> >>> MythTV, but occasionally view TV with "cat /dev/video0 |xine
> >>> stdin:/"
> >>> which works well.
> >>> I'm want to know if I can get closed-captioning to work with this
> >>> setup in MythTV or if I just save a file via "cat /dev/video0
> >>> somefile.mpg". I've tried using ivtvctrl with the "-wcc" and
> >>> "-wraw"
> >>> and made sure to use "-x1" to capture the cc into the MPEG stream.
> >>>
> >> If you do a ivtvctl -x 1 -w wss,cc sometime after you load the ivtv
> >> module then the CC data will be embedded properly. You can then use
> >> your
> >> TVs built-in CC decoder to view the captions while watching
> >> recorded
> >> programs in MythTV; you shouldn't use the MythTV decoder - it's not
> >> compatible with the current method of embedding the data.
> >>
> >
> > I didn't think this would work with decoding/output methods other
> > than
> > PVR-350 decoding/passthrough... i.e., if you were to use MythTV's
> > software MPEG-2 decoding (either ffmpeg or libmpeg2) and regular Xv
> > output, or XvMC decoding & output via a video card. Am I wrong?
> >
> >
> No, I think you're right - it only works if you have the "Use PVR-350
> for decoding" option checked in MythTV. I use that anyway since the XV
> option isn't as smooth during playback. It seems there are tradeoffs
> either way, but for me using the PVR-350 to decode gives me CC and the
> best picture quality, at the expense of broken FF/REW and no time
> stretch capabilities.
OK, thanks. Just wanted to clarify, as the O.P. stated that he has a
PVR-250, not a -350.
Above quote comes from http://www.ivtvdriver.org/pipermail/ivtv-users/2005-November/000267.html
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