[mythtv-users] RE: nvidia new drivers hdtv/interlacing, any benefit for us non HDTV people?

[Chris Vargas]

Hamish wrote:

> I think you should see 
http://www.gossamer-threads.com/lists/mythtv/dev/75514?do=post_view_threaded#75514

> 
> which explains that this isn't true. 
> 
> The TV out of your video card should be interlaced
anyway; your TV 
> requires it. The interlaced modes would only affect
VGA or DVI
> output. 

I'd like someone to confirm that interlacing modes
truly have no effect on tv-out.

If I'm understanding things correctly, interlaced TV
Out (via composite or s-video) should be very useful,
but ONLY IF:

* your capture setup is such that you're preserving TV
fields: that is, your TV tuner card doesn't
deinterlace the TV signal, and your video capture card
and codec of choice  (if separate) doesn't deinterlace
the tuner card's signal.

* your video-out mode isn't scaled. If you use 800x600
for TV-out, you're scaling up from 640x480 and it's
likely that the fields are being affected by that
scaling, even if the resulting output is interlaced
(as is required by the TV)

The PVR-250 and -350 definitely capture and record
interlaced video... if you burn a DVD with an MPEG2
recording from them, it's obvious that the fields are
preserved. The thing I was never able to see, however
(even under Windows with TV-out, various utilities,
Snapstream, etc.), was those fields preserved from the
TV-out of the video card. 

The 350's TV-out preserves those fields, as does the
MediaMVP (which is running Linux).

It also shouldn't be a matter of things being "better"
with properly interlaced TV out: it should be
immediately obvious when viewing live TV events, or
shows that were videotaped rather than filmed. If any
deinterlacing is taking place anywhere in the chain,
it won't look right. It will look more like film than
video. Heck, I can even see it when I play back
recordings of The Daily Show via my MythTV box versus
my MediaMVP box.