[opendtv] Re: Math of oversampling - a simple comparison
- From: "John Willkie" <JohnWillkie@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Sat, 23 Apr 2005 09:32:50 -0700
If you want to fail, sure only beat or match the competition. Then, their
first position tends to wear you down. Very quickly.
You need a "unique selling proposition." Being "almost as good as" or
"slightly better" isn't a USP. Unless you are substantially cheaper, which
tends to affect profit margins.
John Willkie
----- Original Message -----
From: "Tom Barry" <trbarry@xxxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Saturday, April 23, 2005 8:22 AM
Subject: [opendtv] Re: Math of oversampling - a simple comparison
> Bob Miller wrote:
>
> > If a broadcaster uses a 1080p camera and broadcast as 480P and on the
> > reception end it is upconverted to 720P or stays 480P I understand that
> > because of oversampling both the 720P or 480P image would be better than
> > otherwise would be expected. What I would like to do is quantify this
> > value. How would you compare a straight thru 720P broadcast to one such
> > as that above. Would the 1080P>480P>720P route be 75% of the quality of
> > the 720P>720P>720P route? Would 1080P>480P>480P be 110% of
480P>480P>480P?
>
> Bob -
>
> In practice I guess it is only necessary to beat or maybe match
> the competition. 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, using my DctFilter plugin for Avisynth
> (www.trbarry.com/Readme_DctFilter.txt). That filter does a
> discrete cosine transform and then (in this case) zeros out all
> coefficients except for the 4x4 square in the top left of the 8x8
> matrix. Then an inverse transform back to pixels.
>
> Thus the resulting image could theoretically be encoded at only
> 960x544 without any more loss of detail. Of course in practice
> that would introduce additional scaling and compression artifacts.
> I did not do that.
>
> So, without further ado, see for yourself at:
>
> www.trbarry.com/Medium_1080p_compare_qtr_rez.jpg
>
>
> It is not hard to compete with the detail of most HD these days.
> Most of the extra pixels are sadly just being wasted anyway.
>
> - Tom
>
>
>
>
>
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