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

[Geoffrey Kruse]

You need to expand the tar file from within the mythtv directory.  
These files are included with the patch.
i.e.

cd mythtv
tar -xvvzf mythtv_vbi.tar.gz
patch -p0 < mythtv_vbi.patch

Geoff
On Mar 2, 2005, at 9:07 AM, Stutty wrote:

> Have to admit I'm not using the latest CVS (lots of offsets when
> applying patch) but, looks like some files missing from the patch?
>
> e.g. On make I get (amongst others)
> WARNING: Failure to find: vbidecoder.h
> WARNING: Failure to find: vbilut.h
> WARNING: Failure to find: osdtypeteletext.h
> WARNING: Failure to find: vbidecoder.cpp
> WARNING: Failure to find: osdtypeteletext.cpp
>
> Paul
>
>
> On Tue, 1 Mar 2005 22:47:58 +0100, Martin Barnasconi
> <mythtv at barnasconi.net> 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
>>
>>
>> _______________________________________________
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>> mythtv-dev at mythtv.org
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-dev
>>
>>
>>
>>
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