SVM and HDTV ; Good or bad

Archived from groups: alt.tv.tech.hdtv (More info?)

"jean dumont" <jean.dumont@videotron.ca> wrote in message
news_rkc.49775$Fa6.615651@wagner.videotron.net...
> I have been using a Toshiba 42H81 for the last 3 years. I originally
> calibrated the set with the AVIA DVD and the picture was excellent when
> watching DVD but was less than good watching cable. Digital cable was
> especially bad, with lots of visible signal compression, especially with
> sporting events such as hockey and football ; for these I would always
> switch to analog cable, which I thought looked better (less mosquito
effect
> around the moving players).
> I waited about a year until I had the set checked by a certified
technician
> for calibration. After calibration, the image looked somewhat greener (the
> tech guy said there was a slight red push), and after awhile I got
> accustomed to the new setting and liked it. Cable TV was still it's usual
> self though.
> I recently decided to tweak the set myself - about a year after the tech
guy
> came, not really willing to spend another $300 for a new visit. Doing
manual
> focus, I realized the guy did not disable SVM in the first place. So I had
> been watching for a whole 2 years with SVM on all the time.
> I unplugged the power from the 3 SVM boards and looked at the results.
>
> Well, for standard TV, I will agree with what I have been reading all over
> the internet: disabling SVM really makes a difference. It seems that this
> thing tracks down MPEG2 compression artefacts and actually amplifies them.
> With SVM disabled, hockey games look definitely better, although the
overall
> image will appear softer.
>
> HDTV is another story. The image will also be significantly softer, and
the
> difference between a standard broadcast and an HDTV one will appear less
> dramatic in my opinion. I have seen HDTV material that looked fabulous
with
> SVM on ; "Minority Report", Football games, lots of movies. Although
> switching SVM off will make the image somewhat more movie like, SVM on
seems
> to multiply the resolution by a factor of two ; everything looks extremely
> crisp with good material.
>
> While I was adjusting the set, I also reduced the overscan for the HD
input,
> which was considerable. So it's possible that the softness might be
> exagerated by the set's inability to resolve all 1080 scanning lines,
> despite what the specs claims.
>
> I just thought I would post this, since there is so few reports of people
> actually giving SVM credit for anything.
>
>

Archived from groups: alt.tv.tech.hdtv (More info?)

It is interesting that you find this result, but not surprising IME. I
recently suggested that VM might not always be a bad thing and found a
surprising number of people railing against it. I think a lot of the
assumed bias against VM comes from people not understanding exactly what the
circuits are doing and lots of different kinds of circuits getting lumped
together under this label. The manufacturers don't help, as the most you
can get from them is hype in many cases. I think a lot of the folks that
assume that it should be turned off got this misunderstanding from the idea
that for proper calibration you should generally start with the VM disabled.
That does not necessarily mean that it should stay off.

The circuit on your Toshiba, like most that have a separate baord on the
CRT(s) for VM is more of the beam forming sort. Circuits that work at this
level, modulating the control of the beam with an additional coil, as
opposed to "peaking" circuits or those that fiddle with the video response
as applied to the video amps, are often a plus, IMO. You have to judge each
circuit on its effect, however, and decide if you like what it does.

If you like the way it looks, use it.

Leonard

"jean dumont" <jean.dumont@videotron.ca> wrote in message
news_rkc.49775$Fa6.615651@wagner.videotron.net...
> I have been using a Toshiba 42H81 for the last 3 years. I originally
> calibrated the set with the AVIA DVD and the picture was excellent when
> watching DVD but was less than good watching cable. Digital cable was
> especially bad, with lots of visible signal compression, especially with
> sporting events such as hockey and football ; for these I would always
> switch to analog cable, which I thought looked better (less mosquito
effect
> around the moving players).
> I waited about a year until I had the set checked by a certified
technician
> for calibration. After calibration, the image looked somewhat greener (the
> tech guy said there was a slight red push), and after awhile I got
> accustomed to the new setting and liked it. Cable TV was still it's usual
> self though.
> I recently decided to tweak the set myself - about a year after the tech
guy
> came, not really willing to spend another $300 for a new visit. Doing
manual
> focus, I realized the guy did not disable SVM in the first place. So I had
> been watching for a whole 2 years with SVM on all the time.
> I unplugged the power from the 3 SVM boards and looked at the results.
>
> Well, for standard TV, I will agree with what I have been reading all over
> the internet: disabling SVM really makes a difference. It seems that this
> thing tracks down MPEG2 compression artefacts and actually amplifies them.
> With SVM disabled, hockey games look definitely better, although the
overall
> image will appear softer.
>
> HDTV is another story. The image will also be significantly softer, and
the
> difference between a standard broadcast and an HDTV one will appear less
> dramatic in my opinion. I have seen HDTV material that looked fabulous
with
> SVM on ; "Minority Report", Football games, lots of movies. Although
> switching SVM off will make the image somewhat more movie like, SVM on
seems
> to multiply the resolution by a factor of two ; everything looks extremely
> crisp with good material.
>
> While I was adjusting the set, I also reduced the overscan for the HD
input,
> which was considerable. So it's possible that the softness might be
> exagerated by the set's inability to resolve all 1080 scanning lines,
> despite what the specs claims.
>
> I just thought I would post this, since there is so few reports of people
> actually giving SVM credit for anything.
>
>

Archived from groups: alt.tv.tech.hdtv (More info?)

Thank you for your explanations. I like it when I know why I should be
happy.

I noticed that partially switching back SVM on (movie mode) will produce
slight moire effects with an cable RF input that do not appear when the
boards are physically unplugged.
Could this be due to the 3DY/C comb filter interaction with the ouput of
VSM? I would have imagined that VSM would have been introduced at the end of
the line of the process chain and the comb filter would not be aware of
it...
Just a thought, maybe this is something else...
"Leonard Caillouet" <lcaillonospam@devoynet.com> wrote in message
news:zyEkc.914$nN6.30@lakeread06...
> It is interesting that you find this result, but not surprising IME. I
> recently suggested that VM might not always be a bad thing and found a
> surprising number of people railing against it. I think a lot of the
> assumed bias against VM comes from people not understanding exactly what
the
> circuits are doing and lots of different kinds of circuits getting lumped
> together under this label. The manufacturers don't help, as the most you
> can get from them is hype in many cases. I think a lot of the folks that
> assume that it should be turned off got this misunderstanding from the
idea
> that for proper calibration you should generally start with the VM
disabled.
> That does not necessarily mean that it should stay off.
>
> The circuit on your Toshiba, like most that have a separate baord on the
> CRT(s) for VM is more of the beam forming sort. Circuits that work at
this
> level, modulating the control of the beam with an additional coil, as
> opposed to "peaking" circuits or those that fiddle with the video response
> as applied to the video amps, are often a plus, IMO. You have to judge
each
> circuit on its effect, however, and decide if you like what it does.
>
> If you like the way it looks, use it.
>
> Leonard
>
> "jean dumont" <jean.dumont@videotron.ca> wrote in message
> news_rkc.49775$Fa6.615651@wagner.videotron.net...
> > I have been using a Toshiba 42H81 for the last 3 years. I originally
> > calibrated the set with the AVIA DVD and the picture was excellent when
> > watching DVD but was less than good watching cable. Digital cable was
> > especially bad, with lots of visible signal compression, especially with
> > sporting events such as hockey and football ; for these I would always
> > switch to analog cable, which I thought looked better (less mosquito
> effect
> > around the moving players).
> > I waited about a year until I had the set checked by a certified
> technician
> > for calibration. After calibration, the image looked somewhat greener
(the
> > tech guy said there was a slight red push), and after awhile I got
> > accustomed to the new setting and liked it. Cable TV was still it's
usual
> > self though.
> > I recently decided to tweak the set myself - about a year after the tech
> guy
> > came, not really willing to spend another $300 for a new visit. Doing
> manual
> > focus, I realized the guy did not disable SVM in the first place. So I
had
> > been watching for a whole 2 years with SVM on all the time.
> > I unplugged the power from the 3 SVM boards and looked at the results.
> >
> > Well, for standard TV, I will agree with what I have been reading all
over
> > the internet: disabling SVM really makes a difference. It seems that
this
> > thing tracks down MPEG2 compression artefacts and actually amplifies
them.
> > With SVM disabled, hockey games look definitely better, although the
> overall
> > image will appear softer.
> >
> > HDTV is another story. The image will also be significantly softer, and
> the
> > difference between a standard broadcast and an HDTV one will appear less
> > dramatic in my opinion. I have seen HDTV material that looked fabulous
> with
> > SVM on ; "Minority Report", Football games, lots of movies. Although
> > switching SVM off will make the image somewhat more movie like, SVM on
> seems
> > to multiply the resolution by a factor of two ; everything looks
extremely
> > crisp with good material.
> >
> > While I was adjusting the set, I also reduced the overscan for the HD
> input,
> > which was considerable. So it's possible that the softness might be
> > exagerated by the set's inability to resolve all 1080 scanning lines,
> > despite what the specs claims.
> >
> > I just thought I would post this, since there is so few reports of
people
> > actually giving SVM credit for anything.
> >
> >
>
>