[mythtv-users] HDTV Output/Deinterlacing

Brad Templeton brad+myth at templetons.com
Wed Dec 15 08:19:56 UTC 2004

On Tue, Dec 14, 2004 at 10:37:37PM -0500, Dave wrote:
> Hi,
>    I've been following this list for sometime now, paying particular
> attention to those who are capturing/outputting HD
>    I've seen a lot of posts from poeple telling others to turn on the
> deinterlacer, or that playback is better with the deinterlacer on. 
> Given that the modelines I've seen are set to output 720p or 1080i,
> what are we deinterlacing for?
>    Assuming that the TV supports inputs of 720p and 1080i, can't the
> original format just be passed straight to the TV?
>    My thinking is (and I'm probably way off :) ) if the TV has a ATSC
> tuner, and both 1080i and 720p pictures look "as expected", there
> should be no loss in quality when feeding a 1080i or 720p input from a
> vieo card.

Many HDTVs only take 1080i.  If they do take both, you would need Myth
to switch to different modes depending on the recording being played.  I
don't know if it is smart enough to do that.

What would be cute would be if they made a cheap ATSC or QAM modulator,
and you could stream the MP3s to tuner-equipped TVs over RF!

The one thing you never wanted to do with your video equipment -- doing
RF on channel 3 -- turns out to be a good idea with digital, sure to
give the purest signal.   DTVLink would also be a good way to do this.

However, you would have to write an X windows driver that output as
mpeg, and OSD would be an interesting challege.  But you would get
the cleanest signal possible, presuming your TV has a good decoder,
with no CPU load (except when doing OSD).   Better than component
video, better than DVI.

No video card needed, just an RF modulator.   Since all HDTVs are now
being required to have ATSC tuners, it might make a lot of sense for
a HDTV card to feature this ATSC modulator.

For the future.

More information about the mythtv-users mailing list