[opendtv] Re: Math of oversampling - a simple comparison
- From: "John Willkie" <JohnWillkie@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Tue, 26 Apr 2005 21:27:29 -0700
gee, this is quite relevant to still images. Aren't we about MOVING images?
John Willkie
----- Original Message -----
From: "Tom Barry" <trbarry@xxxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Tuesday, April 26, 2005 6:25 PM
Subject: [opendtv] Re: Math of oversampling - a simple comparison
> Doug -
>
> Okay, here's one from Leno. I had to wait to record it last
> night. As before the left half of the image is the original and
> the right half is filtered to an effective 1/4 resolution of only
> 960x544, though no actual resizing was done.
>
> As you suggested, a discerning viewer can probably tell the
> difference a bit more easily here. I'll let everyone else decide
> whether it looks like it justifies 4 times as many pixels, though
> of course not 4x the bandwidth.
>
> See: www.trbarry.com/Leno_1080p_compare_qtr_rez.jpg
>
> And for Internet Explorer users, be sure to remember to zoom it to
> full size before comparing since your browser may otherwise just
> auto-fit it to your screen.
>
> - Tom
>
>
> Doug McDonald wrote:
>
> > Tom Barry wrote:
> >
> >>Doug McDonald wrote:
> >>
> >>The tests couldn't be done fairly if it was interlaced 1080i from
> >>video cameras since I'd have to deinterlace it and be accused of
> >>losing some detail that way. Isn't Leno video source?
> >
> >
> > Yes, and that's the point. It looks simply great. If you
> > convert it to STDV, it will look awful. Interlace is immaterial ...
> > it can only hurt. Pick a scene where the camera is static
> > and the talking heads not moving.
> >
> >
> >>And I don't think anybody would be very impressed if I showed a
> >>544p image could look close to a 720p image. They are just too
> >>close anyway.
> >
> >
> > That's where you are wrong, with the first rate 720p. Try some
> > ABC sitcoms ... at 720p you will easily read the notes stuck
> > to teh refrigerator ... at less than that you won't.
> >
> >
> >
> >>But if you can suggest a 1080p (or telecined 1080i)
> >
> >
> > What we don't want is telecined ... for some reason that
> > does not look as good.
> >
> > Doug McDonald
> >
> >
> >
> > OTA or cable
> >
> >>source I can easily record or or any download I'd be glad to do
> >>the test again on your source material. Pick the best one you can
> >>name.
> >>
> >>- Tom
> >>
> >>
> >>
> >>
> >>>Tom Barry wrote:
> >>>
> >>>
> >>>
> >>>>And currently most HDTV does not really contain
> >>>>that much detail. I have included a link to a captured image from
> >>>>the Pilot of the Medium TV series. The LEFT half of that image
> >>>>was left untouched.
> >>>>
> >>>>But on the RIGHT half of the image I filtered out all frequencies
> >>>>that would correspond to a spatial resolution higher than a 1/4
> >>>>rez of 960x544,
> >>>
> >>>
> >>>
> >>>That is simply a TERRIBLE image to compare on, nevertheless,
> >>>the right half shows a noticeable case of the dread edge engancement.
> >>>It is terribly out of focus for most of the image.
> >>>
> >>>
> >>>I suggest using a much better test: for example, Leno or one of the
> >>>better ABC sitcoms (e.g. Less Than Perfect) with a far shot,
> >>>or really good sports shots in 720p or 1080i.
> >>>
> >>>Doug McDonald
> >>>
> >>>
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> >>
> >>
> >>
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> >
> >
> >
> >
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