[mythtv-users] What is temporal spatial deinterlacing, and how do I get it?

[Brad Templeton]

On Wed, Feb 25, 2009 at 04:14:30PM +0000, Paul Gardiner wrote:
> Tom Dexter wrote:
>> Thanks for the reply Seth.  That does sound pretty nice.  I may give
>> it a try at some point, though I need a new video card to support
>> it...I have a 7100GS card.
>>
>> One thing confuses me though.  I use that same patch you're referring
>> to (to allow Bob 2x on 1080i output).  When you use VDPAU and enable
>> Bob 2x, the Bob deinterlacing is handled by VDPAU?
>>
>> Other than the performance improvement, do you see a noticeable
>> improvement in the picture quality using it?
>
> For 1080i output, Bob 2x should give the best results of all - better
> than any other deinterlacer, because with 1080i output, you don't
> want any processing of the interlaces, you just want them passed
> out in sync. Having said that, I have no idea how you are always
> getting them in sync. I'd expect half the time that you'd get the
> interlaces being displayed spatially reversed. Perhaps nVidia
> have a trick to keep them in sync.
>

The description of bob 2x at http://www.mythtv.org/wiki/Deinterlacing
differs from this but I suspect it is wrong.  I thought that box 2x
displayed at 60 frames/second showing the current field every other
line mixed with the previous field in alternate lines, like a TV with
1/30th second persistence does.

It would be great if this page were expanded by people who had
experimented a lot with different interlacing techniques.  People
want to know things like:

    a) Which methods will look best with different types of video
    b) How much CPU is needed for 480i and 1080i for the various
        methods
    c) The VDPAU methods, and which are best and what cards can
       handle 1080i with them using how much CPU

(It also needs updating of the screen shot as now Myth uses the
resolution based profiles to control the deinterlace and
backup deinterlace.)

I admit to only having played with this modestly so I am not up
to writing all of this, but it is becoming one of the more
common questions here so it deserves updating.  And the note
about nvidia needs an update if it's true that trying to drive
your screen interlaced often fails.

Then another section on transcode interlacing would be nice, but
as far as I can tell, this doesn't work at all.  I have tried putting
deinterlacers in the filters field of mythtranscode and the output
is still always interlaced.  (this is with trunk)