[opendtv] Re: 20060117 Mark's (Almost) Monday Memo

  • From: Tom Barry <trbarry@xxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Wed, 18 Jan 2006 08:37:28 -0500


Richard Hollandsworth wrote:
> Many 1080i sets look as good as a 1080p set because they deinterlace in=
to  a picture buffer and then read it out at much higher than 30 fps, jus=
t like a computer monitor can spit out the same image at 60, 72, 75 Hz, e=
tc.
> Note VirtualHD 1080p processing in my 2003 Hitachi 42-inch Plasma, whic=
h is capable of 1280x1024@75 fps on the VGA port (see attached brocure).
>=20

On a PC, once you have progressive frames in a buffer you can easily=20
output at any frame rate the video card supports, without any special=20
logic at all as long as you don't need any sort of "Natural Motion"=20
interpolation.  We did this in the open source DScaler project for=20
instance, where 72 Hz was popular.

But the hard part is getting progressive frames in a buffer when the=20
source is truly interlaced.  Then it's a quality contest between=20
upscaled 60p frames vs the constructed frames created from 30i.  And it=20
gets even more interesting when you have mixed material constantly=20
switching back and forth between interlaced and telecined material.

I think interlaced material gets its advantage by allowing a little=20
vertical aliasing, sending material with more than 540 vertical pixels=20
of resolution.  The human visual system can resolve some of the=20
ambiguity caused by this aliasing and we are politely willing to=20
overlook a small amount of artifacts in order to get the extra detail.

I keep expecting this equation to change as we all start getting 1080p=20
displays since one of the driving forces to interlaced format will=20
disappear.  So I still expect interlaced delivery to also eventually=20
disappear.  But, for whatever reasons, my poll didn't support all this=20
conjecture yet.  I believe Mark's explanation was likely on track there.

If I thought there would have been enough respondents I would have had=20
the poll ask only about live sports broadcasts which seem to be all from =

30i or 60p video cameras.

- Tom


> PS: Sears has the similiar Hitachi 42HDM12 Monitor (Alis 1024x1024) on =
sale for $1,979:
> http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=3DYes&vertical=
=3DELEC&pid=3D05775725000&subcat=3D38+to+51+inch+TVs
>=20
>                   <holl_ands>
>=20
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D
> Tom Barry <trbarry@xxxxxxxxxxx> wrote:=20
>=20
> Manfredi, Albert E wrote:
>=20
>>Mark Schubin wrote:
>>
>>
>>
>>>    - This story from Connected Home Media I liked for one
>>>of the headlines.  Did you know 2006 will be "The Year of
>>>HDTV"?
>>>
>>
>>
>>I think what the paragraph actually describes is the year of
>>1080p. Which The Perfect Vision is also claiming. In which
>>case, the interesting question (IMO) would be what looks
>>better on a 1080 at 60p display? 720p upconverted, or 1080i
>>deinterlaced?
>=20
>=20
> I'm running an AVS poll on that very subject right now for those that=20
> recently got a 1080p display for Xmas, or wherever.  The results=20
> strongly suggest (against my expectations) that deinterlaced 1080i is=20
> superior.  Though the number of respondents is still small (30 with a=20
> 1080p display).  See:
>=20
>=20
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> It is always a mystery to me why 1080i continues to do so well but it=20
> often looks better to me too.  But I don't have a 1080p display yet.
>=20
> - Tom
>=20
>=20
>=20
>=20
>       =09
> ---------------------------------
> Yahoo! Photos =96 Showcase holiday pictures in hardcover
>  Photo Books. You design it and we=92ll bind it!
>=20
>=20
> -- Binary/unsupported file stripped by Ecartis --
> -- Type: application/pdf
> -- File: Hitachi 42HDT50 SpecSheet incl VirtualHD 1080p Proc.pdf
> -- Desc: 3527817690-Hitachi 42HDT50 SpecSheet incl VirtualHD 1080p Proc=
=2Epdf
>=20
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> =20
> =20
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