IRE 7.5 vs. IRE 0
Pat
I generally understand the definitions and history of the analog "relative
measure" for SETUP (aka PEDESTAL) that defines BLACK. Which is 7.5% UP from
Zero Volts on a 0-100 scale, layed across a corresponding voltage of ZERO
to X (where, X = the white level voltage, e.g. 735 Millivolts and varies
with region).
(1) Is this totally a hardware setting, where the analog or digital source
video is neutral in the process?
CASE #1
HARDWARE: Videotape player outputing IRE 7.5 (US) to the analog input of
your TV setup at IRE 7.5 (US).
(2) What if your NTSC videotape source is from Japan and was recorded there,
at IRE 0. Is the Japanese videotape going to display properly on the US
Videotape player and TV, both setup at IRE 7.5?
(3) If you're capturing a Videotape in the US, via a Canopus ADVC-100, then
IRE 7.5 is the right setting. However, if you play the Japanese made NTSC
Videotape (above), should you capture by setting the Canopus at IRE 0
(Japan) or IRE 7.5 (US)?
CASE #2
US DVD Player with IRE 7.5 analog output.
Here, the Luma range on all your DVDs is going to be 16-235 based on
standards..
(4) When played back, are all DVDs (US and Japanese) set to the 16-235
range, by convention?
(5) Is it true that the digital Luma range (16-235) on DVDs, is a separate
and distinct thing from the analog IRE setting on players and TV sets? The
first being source material (Videotapes and DVD discs) and the second being
analog hardware (players and TV sets).
Thanks,
Pat
Richard Crowley
> I generally understand the definitions and history of the
> analog "relative measure" for SETUP (aka PEDESTAL)
> that defines BLACK. Which is 7.5% UP from Zero Volts
> on a 0-100 scale, layed across a corresponding voltage of
> ZERO to X (where, X = the white level voltage, e.g. 735
> Millivolts and varies with region).
>
> (1) Is this totally a hardware setting, where the analog or
> digital source video is neutral in the process?
It is likely not as simple as that in the real world. Take the
near infinite number of combinations of hardware and software,
and multiply that by the near infinite number of ways of
interpereting and/or executing the "standards". This is why
professionals use waveform monitors and colorbar test
patterns and custom-tune each playback.
> CASE #1
>
> HARDWARE: Videotape player outputing IRE 7.5 (US)
> to the analog input of your TV setup at IRE 7.5 (US).
>
> (2) What if your NTSC videotape source is from Japan
> and was recorded there, at IRE 0. Is the Japanese videotape
> going to display properly on the US Videotape player and
> TV, both setup at IRE 7.5?
No, it will likely NOT display properly. You will probably
lose details in lowlights ("black compression") This is one
reason why TV/monitors have brightness and contrast user
controls.
> (3) If you're capturing a Videotape in the US, via a Canopus
> ADVC-100, then IRE 7.5 is the right setting. However, if you
> play the Japanese made NTSC Videotape (above), should you
> capture by setting the Canopus at IRE 0 (Japan) or IRE 7.5 (US)?
You would likely have to set the ADVC-100 to "0" to match
the tape. But actual real-world experience trumps theory. May
be variations in how VCRs (pro vs. consumer) reproduce the
signal.
> CASE #2
>
> US DVD Player with IRE 7.5 analog output.
You might be better off asking in one of the (many) DVD newsgroups.
Pat
"Richard Crowley" <rcro...@xprt.net> wrote in message
news:100aq5d...@corp.supernews.com...
> "Pat" wrote ...
> > I generally understand the definitions and history of the
> > analog "relative measure" for SETUP (aka PEDESTAL)
> > that defines BLACK. Which is 7.5% UP from Zero Volts
> > on a 0-100 scale, layed across a corresponding voltage of
> > ZERO to X (where, X = the white level voltage, e.g. 735
> > Millivolts and varies with region).
> >
> > (1) Is this totally a hardware setting, where the analog or
> > digital source video is neutral in the process?
>
> It is likely not as simple as that in the real world. Take the
> near infinite number of combinations of hardware and software,
> and multiply that by the near infinite number of ways of
> interpereting and/or executing the "standards". This is why
> professionals use waveform monitors and colorbar test
> patterns and custom-tune each playback.
If all you have is a VHS deck and a Canopus capture box, what is the
recommended way to get the Luma range right? Do you try first to capture at
IRE 0 and then a sample at IRE 7.5, then check the resulting video? In
adddition, is it possible that if you capture analog with the wrong black
level, that you can correct this using Vegas 4, for example?
Richard Crowley
> If all you have is a VHS deck and a Canopus capture box,
> what is the recommended way to get the Luma range right?
> Do you try first to capture at IRE 0 and then a sample at IRE
> 7.5, then check the resulting video?
Sounds reasonabale to me. Do you have a good color bar signal
with the "PLUGE Bars" (the three gray vertical bars in the lower
right corner). Download one and play it back through the Canopus
to see how (if?) your video monitor is anywhere near calibration.
http://www.videouniversity.com/tvbars2.htm
> In adddition, is it possible that if you capture analog with
> the wrong black level, that you can correct this using Vegas
> 4, for example?
Without any specific knowledge of Vegas 4 (or any other number)
my guess would be that it is likely you can effect some sort of
correction. Maybe OK for short clips, but far better to capture
properly than to "fix it in post".
Juan Parra
http://pro.jvc.com/pro/attributes/prodv/clips/blacksetup/JVC_DEMO.swf
please ignore the company marketing.
juani
"Richard Crowley" <rcro...@xprt.net> wrote in message
news:100c6vk...@corp.supernews.com...
Richard Crowley
"Juan Parra" <ju...@yahoo.com> wrote in message
news:BfyNb.109803$JQ1.32551@pd7tw1no...
> check this out:
>
> http://pro.jvc.com/pro/attributes/prodv/clips/blacksetup/JVC_DEMO.swf
>
> please ignore the company marketing.
That is easy to ignore. "Server not found"
AnthonyR
It was an excellent tutorial on the use of black level setup.
I enjoyed it and it taught me a few things to watch out for.
AnthonyR
"Juan Parra" <ju...@yahoo.com> wrote in message
news:BfyNb.109803$JQ1.32551@pd7tw1no...
Pat
what JVC has at the CES show last week in Las Vegas?
"Juan Parra" <ju...@yahoo.com> wrote in message
news:BfyNb.109803$JQ1.32551@pd7tw1no...