[xine-devel] interlace support

[Guenter B. <bar...@st...>]

Hi Michel,

> > - do you have an idea how to display interlaced streams correctly?
> >   I though about rendering two half-height frames in mpeg2dec
> >   and displaying them at 50/60 fps and stretching them (at zero cost
> >   with Xv :)) - do you think that's the correct way to implement that?

> I think there is no way to correctly display interlaced streams on a
> progressive display. Some information has been thrown out and all
> solutions to this problem will have their own problems too :( I think
> I will just put two fields together and output the resulting frame at
> once. This is the correct behaviour for mostly static scenes. However
> it does suck as soon as you have fast motion. You cant do fast-motion
> right anyway except if your display runs at the same frequency as the
> fields in the coded movie. 

hmmm ... but there must be a better solution than those artefacts produced
by displaying both frames simulateously. Don't you think displaying the
half-frames with doubled scan lines at double-frame rate (25->50 30->60
Hz) would help? 

Do you know how the windows-dvd-players do this? I noticed most of them
have two option - weave and bob. Is weave what you're doing in mpeg2dec
now and bob what I'd like to implement?

> Also I'm not sure about this, but I think the progressive-scan TV sets
> must do something pretty complex to have not-too-lousy output - like,
> try to estimate motion vectors and then do time interpolation to
> reconstruct the missing fields ????

sounds really complicated to me and I'm not sure if we have
(computing) time for that. Do we really need to find the perfect solution
or shouldn't we go for something "good enough" for now, I mean - a
solution that looks reasonable even if it isn't mathematically correct?

Regards,

   Guenter