[MPlayer-cvslog] r23530 - in trunk: Changelog DOCS/man/en/mplayer.1 DOCS/tech/MAINTAINERS DOCS/tech/slave.txt cfg-common.h command.c configure input/input.c input/input.h libvo/sub.c libvo/sub.h mpcommon.c mplayer.c spudec.c spudec.h stream/Makef

Michael Niedermayer michaelni at gmx.at
Mon Jun 11 13:50:07 CEST 2007


On Mon, Jun 11, 2007 at 04:19:49PM +0700, Vladimir Voroshilov wrote:
> 2007/6/11, Michael Niedermayer <michaelni at gmx.at>:
> > Hi
> >
> > On Mon, Jun 11, 2007 at 10:31:19AM +0700, Vladimir Voroshilov wrote:
> > > 2007/6/11, Michael Niedermayer <michaelni at gmx.at>:
> > > > Hi
> > > >
> > > > ive not really looked at the patch/commit but 77k for teletext decoding
> > > > with some external lib .... hmm
> > > > ive written a teletext decoder in 1999 and that was <22k including
> > > > demodulation, error correcting, color, caching of pages and subpages
> > > Main code is about 30k (without comments). 10k - rendering, other 30k
> > > is properties/slave commands implementation/configure/interface with
> > > mplayer internals.
> > >
> > > Is it to possible integrate your implementation
> >
> > my code is not related to mplayer and is a huge mess. ive just written
> > it for fun in 98 or 99 or so. writing clean or portable code was not my
> > goal when i wrote it, just getting it well working was enough ...
> >
> > either way ive attached the relevant files, feel free to use anything from
> > it under LGPL or GPL if you like but i doubt theres much directly useable
> Seems like my knowledge is not enough to unsestand this code after quick look.
> > > (i'll prefer solution
> > > without external lib)?
> >
> > me too but i dont know if its possible with v4l*, can it portably capture
> > the lines which contain teletext?
> >
> v4l2 contains "Raw VBI Data interface" and "Sliced VBI Data interface"
> Is that what you are asking about ?
> Used in teletext patch zvbi library works with v4l,v4l2 or bktr

so v4l* has everything that we need, no external libs needed

the modulation
used by teletext is as simple as one could modulate the data, sample > 50%
brightness its a 1 bit otherwise its a 0 bit, the error correction is a
8,4 hamming code for control and 1 parity bit to 7 bit for text you dont need
an external lib for doing these, also the apparent lack of subpage support
is scaring me, theres nothing special or tricky about subpages

also looking at zvbis upcomming features
* Multi-station Teletext page cache
that one my code supported 8 years ago already ...

* Teletext and CC caption/subtitle recording in formats like MPSub, 
  QuickTime Text, SAMI or SubViewer, with color, styles and position 
  preserved as far as possible
that one qualifies the lib as something i will never ever install on
any system i own

PS: and yes i do vote for reverting the patch and i vote against any
patch using an external lib for teletext decoding theres no need for
this, teletext is very simple

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you really think that XML is the answer, then you definitly missunderstood
the question -- Attila Kinali
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