[mythtv] [experimental patch] vbi decoder for IVTV cards

[Geoffrey Kruse]

I get some undefined symbols when compiling on OS X  (could be just OS 
X?).  I will try the patch on my x86 linux box later tonight.

Geoff

ld: Undefined symbols:
VbiDecoder::VbiDecoder()
OSDTypeTeletext::OSDTypeTeletext(QString const&, QRect, TTFFont*)
OSDTypeTeletext::Reinit(float, float)
OSDTypeTeletext::OSDTypeTeletext(OSDTypeTeletext const&)
TeletextView::setDecoder(VbiDecoder*)
VbiDecoder::processVbiData(unsigned char*)
make[2]: *** [libmythtv-0.17.0.17.0.dylib] Error 1
make[1]: *** [sub-libmythtv] Error 2
make: *** [sub-libs] Error 2

On Mar 1, 2005, at 1:47 PM, Martin Barnasconi wrote:

> Here the first experimental patch for the vbi decoding for PVR cards 
> using the
> IVTV drivers. Although its far from perfect (that's why it's 
> classified as
> experimental;-) it gives you some idea how things are implemented and I
> challenge you to contribute to fill in the missing gaps or to improve 
> the
> code.
>
> What it does:
> it relies on having embedded vbi in the MPEG stream as defined in the 
> IVTV
> doc's. The embedded vbi stream includes the magic cookies "itv0' and 
> 'ITV0'
> to mark the beginning of a vbi private stream. That's why some 
> additional
> lines are added to the avformatdecoder and ffmpeg decoder classes, to
> recognize a vbi data steam. If detected, it will start decoding in the
> vbidecoder class. An additional OSD overlay osdtypeteletext is used for
> teletext and subtitles. Whole process is controlled from tv_play 
> routines.
> Pages are updated after receiving new content, so even subtitling 
> pages (e.g.
> 888) do work!
>
> What it does not do yet (TODO ;-)
> - It overrules the 'T' key for teletext/CC for non-encoder cards
> (bttv/saa7134) . The original vbi code (part of 
> nuppelvideoplayer/recorder)
> is still in, but I rather see this becoming part of this new vbidecoder
> class. Like to see 'C' for CC/subtitles and 'T' for teletext. Problem: 
> 'C'
> function already in use...
> As some people have a mixed PVR/bttv setup, we should detect which 
> card is
> operational and select the correct vbi decoder.
> - CC is not working yet, as we do not have this here in Europe. Please 
> test
> the results in ccbuffer and in your stderr terminal and please report 
> your
> findings.
> - Teletext is text-only. No mosaic or other fancy stuff like blanking, 
> FLOF,
> blicking, reveal functions yet. Uses current CC_font in OSD. Should be
> teletext font in future. for the OSD overlay, we suffer from the color
> mapping of YUV420 here. Use a font with sufficient width (eg bold 
> fonts) to
> be able to read the blue or red text.
> - other embedded data like WSS/PIL/CNI/VPS/PDC captured but not used.
> Framework in place, detection and corresponding actions (e.g. signals 
> and
> slots) to be defined.
> - TT OSD overlay is now transparent. Future work is to have black,
> transparent, or even left-TV/right-TT (for 16:9 screens) or TT-PIP
> implemented (for big screens)
>
> Give it a try and report your findings. Improvements are very welcome.
>
> Martin
> <mythtv_vbi.tar.gz>_______________________________________________
> mythtv-dev mailing list
> mythtv-dev at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-dev
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