Glen,

Thank you for your response and the very informative link. I also ordered the VASST color correction DVD in the hopes of learning more.

Thanks again.

Glad to have helped!

Hello,

I have the same Canopus unit. It gets a little tricky depending on your workflow and other equipment but hopefully this will help to clear things up.

Basically the ADVC-100 IRE switch affects both the analog input and output of the unit. The firewire connection is not affected.

So in your case when inputing (converting to DV) VHS footage through the ADVC-100 you need to set the IRE level to whatever your source footage was recorded at. If you are inputing United States NTSC VHS it will have been originally recorded with 7.5 IRE set-up. Therefore set the Canopus unit to 7.5 IRE ON.

Note: The DV Standard is 0 IRE so it will convert the footage to this level and it should stay that way from now on. The only exception is when you dub back to VHS. In that case you need to add set-up again. Here its gets tricky. My Sony DV recorder does not add set-up to the analog outputs so I have to do it through a proc-amp or the Canopus unit with 7.5 IRE set to ON. Some of the JVC DV units on the otherhand do add set-up. So you need to find out what your output deck does to it's analog outputs when dubbing from DV to VHS.

When encoding straight to DVD the DV file color corrected at 0 IRE will look right because DVD players seem to add their own set-up. So basically the only time you add set-up on the output stage is if you are going back to analog video.

One more thing: I use the ADVC-100 to convert my digtal output from vegas to analog for my video monitor. I have the IRE set to ON (7.5). My monitor was then calibrated to SMPTE color bars using this signal. This makes sense because NTSC TVs expect set-up. This has worked well for me and my final videos have a consistent color/level balance on most sets.

Also my Vegas scope settings are 7.5 IRE (unchecked) and studio RGB (checked).

Some of this may not be clear so please feel free to ask for clarification and if anything I say seems off base to anyone I'm open to correction.

Marc

One thing I should add is that you could add your set-up with Vegas using levels or similar effects but you would not want to use that file for the DVD or archive mastering onto DV since DV standard is 0IRE (no set-up).

Marc

In case you just wanted simple reply:

QUESTION:
For workflow 1) Shoud I have the Canopus ADVC100 7.5IRE setup switch "on" or "off" for digitizing VHS ?

ON

Shoud I have the 7.5IRE switch "on" or "off" for external preview during editing ?

ON (But make sure you calibrate your monitor properly)

For workflow 2), should I have the Canopus ADVC100 7.5IRE setup switch "on" or "off" for external preview during editing ?

ON (But make sure you calibrate your monitor properly)

Hey Marc,

I think you're confusing the units.

DV stores video in 8-bit Y'CbCr codes. Standard/proper DV black level is at 16 (Y'). Same with MPEG2/DVD.

IRE doesn't apply because DV works with digital values, not analog.

Glenn, I kinda understand what you are saying - . . . nope, I don't understand what you are saying, and I really want to. Could you put it another way? Please?

As always, I derive much clarity from your knowledge, but this is beating me up a bit, somewhat.

Maybe, could you "group" what you are saying? Bit like a table?

TIA - g

It's really simple.

There's no setup on DV.
There is on NTSC analogue video (if you live in the USA, if not check).
So your analogue interface should have the 7.5 IRE switch ON regardless of if you're going in or out.

And your digital scopes shouldn't have setup on either cause the A/D converter adds and removes it as required. Analogue scopes most likely should have it on, depending on which variant of NTSC you're dealing with.

Bob.

Hey Marc,

I think you're confusing the units. DV stores video in 8-bit Y'CbCr codes. Standard/proper DV black level is at 16 (Y'). Same with MPEG2/DVD.
IRE doesn't apply because DV works with digital values, not analog.

Hi Glenn,

I may have over complicated it in my explanation but my post agrees with you about DV having no set-up. However he is also working with analog video which does have set-up so proper adjustments need to made in order to interface properly with the DV world. I think Farss' explanation above says it simply and clearly.

Marc

Marc

Hey Grazie,

The following article has a table and hopefully clarifies things:
http://glennchan.info/articles/technical/setup/75IREsetup.html

Basically, there are three different standard levels you typically deal with with:

(Analog) Black level at 0 IRE. This is the standard for Japan NTSC, PAL. Most North American DV equipment does this (even though it shouldn't).
(Analog) Black level at 7.5 IRE. This is the standard for non-Japan NTSC.

(Digital) Black level at 16 (Y').

Problems typically occur when you convert from digital<-->analog, since most (North American) DV equipment performs the incorrect, non-standard conversion. Most devices will map 16 (Y') to 0 IRE instead of 7.5 IRE. When that happens, you may need (convoluted) workarounds.

If your DV device (i.e. the Canopus box) can perform the proper conversion, then you don't need those workarounds.

2- The scopes in Vegas: If you set them up incorrectly, they are wrong. This can be very confusing and problematic!!

To keep things simple, you can just use them to monitor digital levels.

A- Make sure you are using the default Vegas DV codec. Other codecs can throw off your results.
B- In the scopes settings, make sure the studio RGB setting is checked.
C- Ignore the waveform monitor.
D- Look at the histogram. "16" (histogram units) corresponds to 16 (Y'), or proper digital black level. 235 (histogram) corresponds to proper digital white level, which is 235 (Y').

2b- Vegas' WFM were sort of designed to mimic an analog hardware waveform monitor. In my opinion, this is very bad design. For starters, it's confusing to everyone trying to figure out the 7.5 IRE setup issue. Secondly, Vegas' WFM doesn't measure analog video levels, so it can't accurately represent them. And lastly, there is no 7.5 marking (which all analog WFMs have).

The practical thing to do is to ignore the manual. Setup Vegas' WFM as if it were a digital waveform monitor (and it really is more of a digital waveform monitor than an analog one).

Follow steps A to D above.
In the scopes setting, uncheck the 7.5 setting. With the 7.5 setting unchecked, digital black level will correspond to 0 on the scope and digital white level will correspond to 100 on the scope. **The scopes will not show what your analog levels are like.** This is ok. With the scopes setup in this fashion, you can see how your digital values lie.

3- In my opinion, it's confusing to think of everything as "adding", "removal", or having no setup. It's less confusing to think of everything in terms of levels conversions.

Your equipment does one of the following:

#1 - (digital) 16 (Y') <--> 7.5 IRE (analog) *This is the standard for North America.
#2 - (digital) 16 (Y') <--> 0 IRE (analog) *This is not the standard, but a lot of North American DV equipment does this!!

All digital devices want to see digital black level at 16 (Y').
Most North American analog devices want to see black level at 7.5 IRE. If you calibrate an analog monitor, you change what black level it looks for.

In most situations, #2 is happening so you have to figure out some sort of workaround/solution. Had the manufacturers done things correctly in the first place, no workaround would be necessary. For most people, the solution is:
A- Be aware that you shouldn't make important analog dubs or masters. They will have incorrect levels. When you are making digital masters (i.e. DV, DVD, etc.) you don't need to worry about the 7.5 IRE setup issue/problem much.
B- Calibrate your monitor.
C- Be aware that if you have both a DVD player and a DV device hooked up to the monitor, you can only calibrate the monitor to one correctly. So don't freak out if your DVD looks off.
D- Make sure your DVD is getting proper digital levels.

Thanks to all for more good information; the preceding posts collectively answered another question I was grappling with - when to check or uncheck the 7.5IRE and Studio RGB boxes in the Vegas scopes.

I stumbled across this problem inadvertently - I had DV footage that looked OK raw; ran it through some simple cuts and fades edit and in the final output the blacks were crushed, especially on one person's face.

Glen,

"A- Make sure you are using the default Vegas DV codec. Other codecs can throw off your results."

Question--
So are my scopes not good working with HDV m2t or Cineform codecs? That is an important statement about the Vegas DV codec.