[opendtv] Re: Math of oversampling - a simple comparison
- From: Tom Barry <trbarry@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Sat, 23 Apr 2005 12:34:28 -0400
John Willkie wrote:
> 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
>
John -
I cannot argue with any of that ceteris paribus.
But would you personally rather have reliable low bit rate mobile
reception of video like the right side of my sample picture or
"standard ATSC" reception like the left side. ;-)
- Tom
> ----- 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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