[opendtv] Re: Math of oversampling - a simple comparison
- From: Tom Barry <trbarry@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Wed, 27 Apr 2005 00:48:10 -0400
John Willkie wrote:
> gee, this is quite relevant to still images. Aren't we about MOVING images?
>
The effect would be quite similar if I posted an entire clip but I
don't have the web space to do that. That was just one frame from
an hour of Leno that's taking up about 6-7 GB right now on my drive.
- Tom
> 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
>>>>>
>>>>>
>>>>>----------------------------------------------------------------------
>>>>>You can UNSUBSCRIBE from the OpenDTV list in two ways:
>>>>>
>>>>>- Using the UNSUBSCRIBE command in your user configuration settings at
>
> FreeLists.org
>
>>>>>- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
>
> unsubscribe in the subject line.
>
>>>>>
>>>>
>>>>
>>>>----------------------------------------------------------------------
>>>>You can UNSUBSCRIBE from the OpenDTV list in two ways:
>>>>
>>>>- Using the UNSUBSCRIBE command in your user configuration settings at
>
> FreeLists.org
>
>>>>- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
>
> unsubscribe in the subject line.
>
>>>>
>>>
>>>
>>>
>>>----------------------------------------------------------------------
>>>You can UNSUBSCRIBE from the OpenDTV list in two ways:
>>>
>>>- Using the UNSUBSCRIBE command in your user configuration settings at
>
> FreeLists.org
>
>>>- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
>
> unsubscribe in the subject line.
>
>>>
>>
>>----------------------------------------------------------------------
>>You can UNSUBSCRIBE from the OpenDTV list in two ways:
>>
>>- Using the UNSUBSCRIBE command in your user configuration settings at
>
> FreeLists.org
>
>>- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
>
> unsubscribe in the subject line.
>
>
>
>
> ----------------------------------------------------------------------
> You can UNSUBSCRIBE from the OpenDTV list in two ways:
>
> - Using the UNSUBSCRIBE command in your user configuration settings at
> FreeLists.org
>
> - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
> unsubscribe in the subject line.
>
>
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:
- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
unsubscribe in the subject line.
Other related posts:
