[opendtv] Re: De-interlacing with HQV high quality video processing (was: 1080i vrs 720P)
- From: Craig Birkmaier <craig@xxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Wed, 5 Oct 2005 11:15:58 -0400
I was a consultant to Teranex for a period of time in the late '90s.
We had MANY discussions about the difficulty in doing good
de-interlacing. Let's just say that it is an imperfect science at
best.
Teranex was purchased by Silicon Optix last year after several years
of working together to develop the chip you refer to. It is a
spectacular product! But it is not perfect.
Any time you want to do a shoot-out between a native 720P camera and
a 1080i camera at 50/60 Hz, then compare the images after the 1080i
has been converted to 720P , using the VERY BEST de-interlacing
technology available, I'm ready to be proven wrong.
THERE IS NOT SUBSTITUTE FOR PROPER SAMPLING IN THE FIRST PLACE.
Spatio-temporal undersampling is a crude form of image compression.
It has no legitimate place in a modern television system, with the
possible exception of cheap displays.
Regards
Craig
At 10:45 AM +0200 10/5/05, Jeroen Stessen wrote:
>Hello,=20
>
>Craig wrote:=20
>> The problem comes when you add the additional complexity required to=20
>> deal with interlaced formats. This requires not on image scaling=20
>> capabilities, but sophisticated de-interlacing capabilities. Even=20
>> standards converters that cost more than six figures cannot do a good=20
>> job with de-interlacing, as it is impossible to properly predict the=20
>> information that was not sampled in the first place. It's even worse=20
>> when you have to rely on a $10-20 chip in the decoder/display to do=20
>> the de-interlacing.
>
>Here's an expert opinion that seems to differ from yours:=20
> http://www.videsignline.com/showArticle.jhtml?articleID=3D171201964
>and this is an excellent article to explain a lot of the basics !=20
>
>
><quote>
>Silicon Optix HQV Approach (Pixel-Based Motion Adaptive):
>HQV processing represents the most advanced de-interlacing technique=20
>available: a true pixel-based motion-adaptive approach. With HQV=20
>processing,=20
>motion is identified at the pixel level rather than the frame level. While =
>
>
>it is mathematically impossible to avoid discarding pixels in motion=20
>during=20
>de-interlacing, HQV processing is careful to discard only the pixels that=20
>would cause combing artifacts. Everything else is displayed with full=20
>resolution. Only the pixels that would cause combing are removed.=20
>
>Pixel-based motion-adaptive de-interlacing avoids artifacts in moving=20
>objects and preserves full resolution of non-moving portions of the screen =
>
>
>even if neighboring pixels are in motion.
>
>?Second Stage? Diagonal Interpolation
>To recover some of the detail lost in the areas in motion, HQV processing=20
>implements a multi-direction diagonal filter that reconstructs some of the =
>
>
>lost data at the edges of moving objects, filtering out any ?jaggies.?=20
>This=20
>operation is called ?second-stage? diagonal interpolation because it?s=20
>performed after the deinterlacing, which is the first stage of processing. =
>
>
>Since diagonal interpolation is independent of the de-interlacing process, =
>
>
>competitors have used similar algorithms with their frame-based de-
>interlacing approaches.=20
><unquote>
>
>
>Maybe if you'd first start spending those $20 on a decent chip... ! ;-)=20
>
>Best regards,=20
>-- Jeroen
>
>+-------------------------------+------------------------------------------+
>| From: Jeroen H. Stessen | E-mail: Jeroen.Stessen@xxxxxxxxxxx |
>| Building: SFJ-5.22 Eindhoven | Deptmt.: Philips Applied Technologies |
>| Phone: ++31.40.2732739 | Visiting & mail address: Glaslaan 2 |
>| Mobile: ++31.6.44680021 | NL 5616 LW Eindhoven, the Netherlands |
>| Pager: ++31.6.65133818 | Website: http://www.apptech.philips.com/ =
>
>|
>+-------------------------------+------------------------------------------+
>
>
>
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