[opendtv] Re: De-interlacing with HQV high quality video processing
- From: "Hoffmann, Hans" <hoffmann@xxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Thu, 6 Oct 2005 15:42:48 +0200
Colleagues,
Discussing the de-interlacing technologies is one issue that impacts the
perceived quality and it will important for some legacy reasons in the
studio.
I would almost say that when feeding an uncompressed 720p/50 and an
uncompressed 1080i/25 signal (content critical but not unduly so) to a
high-end non-CRT display (1920x1080) you may see only little difference
(average educated viewer).
But the real issue is what happens in the broadcast window.
The big contributor to the visibility of image artefacts is the compression
format such as MPEG-2, H.264-AVC, proposed SMPTE VC-1 (you my name all of
them). All work better when they have to compress progressive pictures.
Putting MPEG-2 aside as history, we also see that the modern compression
systems in the area between 6 to 18 Mbit/s perform much better with
progressive input signals.=20
Let's discuss this......I am curious on some views.
And then we talk about the full progressive chain.
Regards,
Hans
European Broadcasting Union
Hans Hoffmann - Senior Engineer=20
Technical Department
Ancienne Route 17a
CH-1218 Grand Saconnex Geneva
Switzerland
Tel:+41 22 717 2746
Tel-Mobile: +41 79 249 3550
Fax: +41 22 747 4746
E-Mail: hoffmann@xxxxxx
> -----Original Message-----
> From: opendtv-bounce@xxxxxxxxxxxxx=20
> [mailto:opendtv-bounce@xxxxxxxxxxxxx] On Behalf Of Tom Barry
> Sent: jeudi, 6. octobre 2005 15:26
> To: opendtv@xxxxxxxxxxxxx
> Subject: [opendtv] Re: De-interlacing with HQV high quality=20
> video processing
>=20
>=20
>=20
>=20
> Mark Schubin wrote:
> > I agree.
> >=20
> > When I was first shown the Teranex prototype, they used the classic
> > "Calendar & Train" sequence to demonstrate their=20
> deinterlacing, and they=20
> > pointed to the sheep on the wall as being properly deinterlaced. I=20
> > pointed to the chrome toy as still showing interlace=20
> artifacts. The=20
> > Teranex technical staff said, in effect, "Well, no=20
> deinterlacer can be=20
> > perfect."
> >=20
>=20
> I don't believe deinterlacers will ever be close to perfect,=20
> regardless=20
> of increased computing power. But the benefits of good=20
> deinterlacers is=20
> not really now to further the cause transmission in interlaced format.
>=20
> I think it is instead intended to get better interlaced=20
> pictures on the=20
> increasing number of high rez progressive displays, with the=20
> understanding the darned interlaced material is going to be=20
> transmitted=20
> for awhile anyway for various historical reasons.
>=20
> Though I do believe good deinterlacing becomes trivial if=20
> they were to=20
> stop fighting Nyquist and just properly down sample 1080i (from=20
> progressive source) vertically to an equivalent 540 vertical=20
> resolution=20
> at capture time. It's only the ambiguity caused by aliasing=20
> at higher=20
> attempted vertical resolutions that creates the problems. =20
> Otherwise the=20
> only cost of interlace is probably just in the added complexity.
>=20
> - Tom
>=20
> > TTFN,
> > Mark
> >=20
> >=20
> > Craig Birkmaier wrote:
> >=20
> >=20
> >>I was a consultant to Teranex for a period of time in the=20
> late '90s.=20
> >>We had MANY discussions about the difficulty in doing good=20
> >>de-interlacing. Let's just say that it is an imperfect science at=20
> >>best.
> >>
> >>Teranex was purchased by Silicon Optix last year after=20
> several years=20
> >>of working together to develop the chip you refer to. It is a=20
> >>spectacular product! But it is not perfect.
> >>
> >>Any time you want to do a shoot-out between a native 720P=20
> camera and=20
> >>a 1080i camera at 50/60 Hz, then compare the images after the 1080i=20
> >>has been converted to 720P , using the VERY BEST de-interlacing=20
> >>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.=20
> >>It has no legitimate place in a modern television system, with the=20
> >>possible exception of cheap displays.
> >>
> >>Regards
> >>Craig
> >>
> >>=20
> >>
> >>=20
> >>
> >=20
> > =20
> > =20
> >=20
> ----------------------------------------------------------------------
> > You can UNSUBSCRIBE from the OpenDTV list in two ways:
> >=20
> > - Using the UNSUBSCRIBE command in your user configuration=20
> settings at FreeLists.org=20
> >=20
> > - By sending a message to: opendtv-request@xxxxxxxxxxxxx=20
> with the word unsubscribe in the subject line.
> >=20
> >=20
> =20
> =20
> ----------------------------------------------------------------------
> You can UNSUBSCRIBE from the OpenDTV list in two ways:
>=20
> - Using the UNSUBSCRIBE command in your user configuration=20
> settings at FreeLists.org=20
>=20
> - By sending a message to: opendtv-request@xxxxxxxxxxxxx with=20
> the word unsubscribe in the subject line.
>=20
>=20
**********************************************************************
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
the system manager.
This footnote also confirms that this email message has been swept by
MIMEsweeper for the presence of computer viruses.
www.mimesweeper.com
**********************************************************************
=20
----------------------------------------------------------------------
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: