Ok, in Vegas 4, you have your video scopes. I was using the waveform monitor to look at something, and saw, to my dismay, that my blacks were near 0, and not 7.5. There was no "7.5" mark currently displayed, so I'd have had to guess where that was on the scope. Then I thought to check the settings on the scope, and noticed an unchecked box with "7.5 IRE setup" written next to it. I checked it, thinking it would simply add a dotted line at the 7.5 mark to the scope, and instead, all the information displayed on the monitor, the values of my video levels, jumped up, making the lowest value on there near 7.5. What did I just do? Why did the IRE values change? How do I know if this stuff is NTSC broadcast acceptable? I thought the IRE values were absolute, that is, a certain level of black registers as "x number" on the IRE scale, and now it seems it ain't so.

Checking the 7.5 ire setup box merely adds 7.5 to all the input values. I don't really know why SoFo wrote it this way, but, the only usefulness of that checkbox is when the "Broadcast Colors" plugin with 7.5 IRE setup is being applied to a track. The intent is to match(calibrate) the vectorscope to a 7.5 IRE input.

So. . .I should uncheck it if I want to see the "true" values? I don't use the broadcast colors plugin, at this time. Is there a better, cheap (or even better, free) software waveform monitor I could acquire, that would work with Vegas 4?

Sadly, waveform monitors/vectorscopes are quite expensive, even on Ebay. The situation is that any analog US-NTSC device with an analog output(VCR, DVD set-top player,etc.) will automatically add a 7.5 IRE bias to source material. Digital devices(DV players, cameras) working thru firewire, output 0 IRE, as that's the DV standard. If you want to output a digital signal to an analog NTSC monitor, you need to add the 7.5IRE bias. The best way to add the bias is with a proc amp(process amplifier), available for moderate cost. I am using a DVP-4, available from www.elitevideo.com. Alternatively, you can add the 7.5 IRE "correction" with the Broadcast Color filter. If you show your video on an NTSC analog monitor, you must add this bias or your blacks will be clipped, and that's not pretty. If you will only display on a computer monitor(digital), don't worry about setting the 7.5 IRE bias on your editted streams.

Well, I'm using a Sony NTSC 14m2u monitor to. . .uh. . .monitor my work. I guess that's analogue? So I should just apply the broadcast color filter?

Josh...

It really depends on your final product and how you've calibrated your NTSC monitor.


How are you distributing your output, DV tape or VHS? If you ditribute with DV tape, be sure to note to your customer whether or not you've applied the setup level to the video, and generally, you can go either way. If you distribute via VHS, definitely use the Broadcast Color filter.


Also, be sure to set up your monitor brightness in the right way. You do this by viewing an NTSC colorbar chart and setting the brightness so the center and left pluge bar just blend into each other while you are feeding it a colorbar chart at the right 7.5 IRE bias.

Distribution is a toughie. . .I was hoping to have one all around one. . .the only reason I'd put it on VHS, for sure, at least right now, is for screeners for film festivals (I think screeners is the right word--the one you send them to consider you for submission, NOT the one they actually show if you're accepted). Does the XL1s' bars have the 7.5 bias? or Vegas' ?


Ok sorry. . .I just did a test in Vegas by applying the Broadcast colors filter to a clip, and rendered one out without the 7.5 IRE setup added, and one with it, and I can't tell them apart. Am I not supposed to be able to?

DV never has 7.5 IRE bias!!!....not a DV cam, not Vegas(unless you use the Broadcast colors filter). DV, by definition, is 0 IRE setup. The 7.5 IRE is needed only when final display is on an NTSC analog display, like a TV monitor. If you capture in DV, process in DV, display in DV, you never need to do anything to the setup level.

If you want to show DV on analog display, like a TV screen, you need to add the 7.5 IRE black setup via a proc amp. If you add the 7.5 IRE black setup, you need to add the Broadcast Colors filter to your NLE to prevent black clipping.

Getting more confused? Don't feel bad..it's a hard thing to grasp.

Ummm..your test clip...

it will be hard to see a difference because all the filter does is remap the blacks. the overall result is a slight redux in signal bandwidth, hopefully unnoticeable. You'd need to run both clips thru your monitor, with 7.5 setup added, to see the difference in the blacks. Clipped blacks usually have a muddy appearance rather than pure black. The inverse, that is no setup added on display but the broadcast color filter set to 7.5 IRE, will reduce the bandwidth, as I said, but, will probably go unnoticed.

Let me try to explain it another way...

Here in the good ole US of A, TV analog broadcast devices, which includes a TV set, a VCR, and US market DVD players, they all clip the input video signal below IRE7.5 and above IRE95. So, if you have a video source with RGB colors mapped anywhere below RGB16 and above RGB235, your signal will be arbitrarily clipped. The result of clipping is muddy blacks and blown out hi-lites. The audio analogy is like trying to feed a hot signal to an audio amplifier and clipping the peaks of the signal. In order to avoid clipping, the Broadcast Color filter remaps any colors below IRE 7.5(RGB16) to RGB 16 or above and above IRE95 to RGB235 or below. The remapping is done in a rather smooth curve so no banding occurs.

So, if you're viewing your editting on an analog monitor(AKA TV monitor) you've gotta ask yourself what that monitor is setup for, NTSC standards or not. If it's set for NTSC standard (7.5 IRE setup) then any signal you feed it below 7.5 IRE wil get clipped.

Does this help any?

Yes. . .uh. . .sort of. Basically, the idea is, depending on final output, I may or may not want to use the added setup. If I somehow get something shown on VH1, for instance, I would have to reformat it with the added setup so that when it airs, it doesn't look like ass. . .correct? And that goes for anytime it'll be played through an NTSC device like a VCR, or DVD player, at a a film festival, also right? If not, though, don't worry about it?

And you need the proc amp in conjunction with the broadcast colors filter, correct?

yeah, I think you're getting it.
If you want to monitor your video image on your TV monitor, or play it to your TV monitor with your computer as the source signal(VEGAS4, or whatever), and see it with the same setup level that you'd see it in broadcast, then you need to put a proc amp at the TV monitor input to properly clip the signal coming from your digital source....does that make sense?

Does anyone know whether the S-video or composite video output of a standard video card, like a Matrox Parhelia or a Radeon 9800, output with the 7.5 setup level already added? If these cards already add the 7.5 setup level, you don't need the proc amp. I don't know the answer to this question.

I can tell you I have a pretty old video card, an NVidia Diamond Viper 770D, and that my firewire card is a $75 Pyro 1394 (or whatever that number) basic card.


Guess what I found? While searching through my monitor's various menus, there's a setting that allows you select either 7.5 or 0 IRE as the setup. When I moved it to 7.5, BAMMO! Everything got darker. . . When I went into the NLE, and using the software video scope for reference (with 7.5 setup turned off), and started raising the brightness level till the darkest darks were around 10 IRE, it started to look okay.

ta-daaa!

So, I guess if intend my distribution medium to be film fests, maybe TV shows, whatever, I should shoot as well as edit with the 7.5 bias? And I'm guess this is one of the reasons people's stuff looks so dark on the web?

1-yes
2-I dunno

And one more thing, when calibrating the monitor on the shoot, I should add the in-monitor 7.5 IRE bias before setting it up according to the bars (from the XL1s, SEMPTE bars with no bias, as you said), or after?

And if you don't know about the web question, is the setup confusion issue a reason it might look dark on another TV, or projection screen?

1-before
2-setup level problems don't manifest themselves as pictures that are too dark. The only symptoms I'm familiar with are 1-the blacks being too light or washed out, muddy or 2-excessive color banding in the image.

hey Josh...

check this out....

http://pro.jvc.com/pro/attributes/prodv/clips/blacksetup/JVC_DEMO.swf


it makes it a lot clearer to understand.

Holy crap dude. . .now I'm so confused I think I'm gonna cry. I will never shoot anything again.

Here's another NLE question:

The video scope, in addition to its "add 7.5 IRE setup option", also has a choice to select "Studio RGB 16-235". Now, do I want that checked if I'm not using a proc amp or anything? The tutorial mentioned black was ALWAYS recorded at 16 from DV cameras, but I'm still confused.

I can add setup in camera, to a certain degree. On the tutorial, the guy said that when changing setup levels, if you can see the level change on a monitor as you adjust it, that means that you have a camera that changes both the analog and the digital setup levels, instead of just the analog, right? Well I do, apparently. And tutorial guy also says if this is the case, then you have to add the 7.5 when lighting, but take it away to shoot, and add it again every time you relight?

first...ignore the part about changing when lighting...that was an example that confused me, too. he was talking about what was wrong to do, anyway.

The confusing thing for you, I suppose, may be that IRE and RGB are two different ways of measuring the color mapping. All DV cams map to RGB which is 0-255, BUT, to give DV some headroom, colors are mapped to 16-235 instead of the full range. SOooo, 16 corresponds to pure black and 235 corresponds to pure white. Now, if I speak of this in IRE terms, then I say 100 IRE is pure white, or 235 in RGB. Now the black or setup level is a little more complicated, yes? In IRE, black is 0 or 7.5 depending on the whether it's digital or analog. Both are RGB 16 if the setup level is set right. If it isn't set right, it can be higher or lower, depending on where the setup was fubared.

Confused yet?

Yes. . .so, in my NLE, do I want to assume that everything was correctly setup and leave that box I mentioned above checked? Also, I'm thinking, if I use that switch in my NTSC monitor, the one that lets you add 7.5 IRE setup, and light and shoot to that, that shoot make me safe for NTSC broadcast sources, no? In other words, if I light referring to that, and I don't have any areas in my picture that are totally lost and black, then I should be okay for analogue sources, right?

And what if I just pump up all the blacks/dark areas in post (using color curves or somesuch), till the darkest dark reads 7.5 or above, according to the NLE software waveform monitor WITHOUT the "7.5 IRE setup" box checked. . .is that the same difference?

I just don't wanna be like the guy on the tutorial whose puppy pictures either looked too washed out or too dark, and I'm still not sure how to get there.

Ok, I'm going to try and get things clarified myself as this still confuses me to a bit.

This is what I understand.

1) You can forget about setup until you are going to, or coming from an analog source. For this situation Josh is only talking about output anyway.

2) Josh needs to find out if his camera adds setup when it does the D->A conversion for output to his monitor. If it does, then he can set his monitor to 0 IRE. If it doesn't then he'll need to set it to 7.5 to add the setup itself. That way he can see what it would look like in broadcast.

3) When he output's his final project, depending on how it's done he *may* need to add setup. If he's outputting from comp->camera->VHS then he needs to know if his camera adds setup (as above) and if it does, he's ok, if not he needs to do the broadcast colours thing - right? If he's saying writing a DVD then he has no choice but to do Broadcast colours to make sure it's NTSC happy.

Is this right?

I'm in PAL land so I'm happy but I'd like to understand all this guff anyway.

Aaron

Yes, I second what Aaron said, even though I hadn't thought about half that stuff. . .at least not in those terms. All I want is for my stuff not to look like crap, whether it be airing on a real TV station, or a digital projector.

The only REAL test, short of using a waveform monitor, is to create a test clip, maybe using a black and white 10 step ramp, then play it on a different system. Unfortunatley, testing it on your own system won't work because the error is self compensating within a single system.

Good luck. Oh, and you're right Aaron, you don't want to add setup twice...like once on the video card output and once in the monitor. Most monitors don't have that 7.5 setup switch. I 've read that if your video card or output signal isn't specified as one or the other, it's likely to be 0 IRE.

Okay, were I using an external waveform monitor, during production, would I want to be safe and keep all video levels above 7.5 IRE? Or let the camcorder (or me) do what it (or I) want (s)? Add setup if necessary? This is keeping in mind that I don't have definite plans for final output, except that it'd mostly likely be NTSC.

Yes, by all means, keep it above 7.5 IRE. Many production studios will not accept an NTSC tape that exceeds legal standards. One note in Vegas4, there is a slider called "smoothness". Use this slider to blend the remapped blacks in a gradient rather than a step to avoid banding. I don't know how other pieces of equipment do the remapping.

Sorry, confused again: if I do this during production, that is, while shooting--raising black levels and lighting so as to be above 7.5 IRE, I still need to remap in post with the broadcast colors filter?

Sorry to have confused you....I misunderstood your last question. No, if you raise the levels during production, obviously, there's no need to raise them in post. I would advise you not to raise the levels in production, however. Doing this in production means you're throwing away image information. From that point forward, you're constrained by that choice. If you capture the full range that the camera is able to capture, you always have the original tape to use, your options remain better.

Okay. . .so you recommend what, then? Should I set my monitor only to the 7.5 IRE? So that I have to light. . .uh. . .brighter to get the same result as I would with 0 IRE? Or should I leave everything (monitor, camera) at 0 (though I've recently discovered I like the look of the pedestal lowered two notches from the default setting on the XL1s) and do all the screwing around in post?

Keep in mind that DVD players should auto conform the signal.
So you can burn a DVD with a 0 IRE floor and just leave it at
that (some testing might be in order to confirm this).

If you want multiple output options then I would shoot at 0 IRE.
If output is always NTSC broadcast or you know that for a
particular shoot set the camera up to start at 7.5 IRE and lower
the zebra stripes to something like 90% as well.

Last time I did a 7.5 IRE floor change in Vegas I could definitely
see the changes in the picture. It was almost like a shine through
curtain was put up. Contrast was dropping like a brick.

Yes, I use the following workflow...I do all my work with 0 IRE setup. In POST, when you are ready for the final render and PTT do the setup based on the final distribution, analog or digital. This means your monitor should be set to whatever your final output will be in order to get the right color balance hi-lite and shadow. After applying the Broadcast color filter, since it remaps the blacks, you may also need to apply a color correction filter to fix the contrast and brightness issues Rob mentioned. Be sure to play with the smoothness sliders to minimize these contrast and brightness effects.

A note on the XL1s black level(pedestal) setting. I've been playing with the black level and seem to notice that changing the knob has an affect on the blacks in the viewfinder. I question whether it also affects the black level on the DV tape. I don't think it should have any effect on what gets layed down to tape. As we discussed yesterday, DV pedestal is 0 IRE by definition. You should not be able to reset that during capture. I beleive the black level setting on the camera affects the analog output, but, NOT the DV output. If, in fact, the DV black level is changing, Canon made a BIG mistake.

Well, that's a long story Bill. Canon didn't make a mistake at all
and yes, the level is changed digital on tape as well. You are
correct in the matter that DV by definition is 0 IRE. That's only
true since it allows the pixels to start at 0. But why couldn't
a camera manufacturer only use the 16 - 235 range of that if
they wanted to?

That's what the setup level of the XL1S. It simply moves the
line up. So depending on where the slider is set it will not encode
completely black as 0,0,0 (if it was RGB) but as 15,15,15 for
example.

Why would this be a big mistake? You are asking the camera to
change the setup level, that's what it does.

Rob...

yes, I see. It was confusing me that I was seeing a change in DV black level, but now I understand what you're saying. In tests I've done, it seems that a black level slider setting of -2 sets 7.5IRE. So, you're saying that a slider setting of -4(minimum, whatever that is) is 0 IRE? That would make sense.

That seems to be the case. I've got mine all the way to the left
and I'm getting nice deep blacks (I'm in PAL land).

to add some confusion ..

just where are these 0 blacks ?
and 0 what ? 0 rgb ? 0 ire ?
on scale 16-235 then 16 rgb is 0 ire so is that the 0 black ?
16rgb is the middle pluge which is black level at 7.5 ...
0-255 so is 0 the 0 black ?

i use GL 1 and elura .. i see no 0 blacks .. the only way i see a zero black is with Vegas waveform scale set to 16-235. but 16 is not 0 rgb it is 16rgb which in analog is set up 7.5 ... change the vegas scale to 0-255 and my 0 black moves to 7 ...

HOWEVER !! if i switch Vegas to use the microsoft Dv codec ..
now on a 0-255 scale my blacks are 0 ire ...add set up and the blacks are now 7 ire ... move the scale to 16-235 and the black is now -7 ire add set up and blacks are now back at 0 ire ...

it appears that Vegas codec supports NTSC 601 mapping .. the microsoft dv codec does not ...

my question is what is meant by 0 black .. is that 0 rgb ? or is it 16 rgb ?

In DV speak, 0 black is 0 IRE. In RGB speak, 0 IRE is 16 RGB in a correctly calibrated NTSC system. If your system is erroneously calibrated, 0 IRE could be 32 RGB or 0 RGB.

In analog speak, 0 black is 7.5 IRE. Yes, I think you're right. Vegas4 is referenced to NTSC601.

Are you sure 0 IRE is 16 RGB? I always thought 0 IRE was 0 RGB
and 7.5 IRE was 15-15-15 RGB (basically). Now I'm not from an
NTSC country, so I haven't weaved through all the techincal stuff
on this. But 15 for 0 IRE seems a bit high to me. I could be very
wrong on this ofcourse. You can CALL 7.5 ire 0 black, but I'd
rather not since it is actually grey. So shall we call it 0 grey? <g>

How confusing! I am glad we don't have that in PAL land. Pfff.

The DV "standard" defines the RGB level to extend from RGB16 to RGB 235. While RGB 0 may be possible with some cameras, it's officially an unofficial (re: non-standard) capability. The whole secret to NTSC 601 standard pedestal of 7.5 IRE correction in Vegas4 , is that it remaps the DV luma signal so that 7.5 IRE or lower is 16 RGB. Therefore, in the remapping process, all DV signal levels between 0 IRE and 7.5 IRE are moved to 16 RGB. So, if you have a monitor setup at 7.5 IRE, you still get blacks. If you've left the setup at 0 IRE, all the values between 7.5 and 0 get clipped off, resulting in muddy blacks.

Yeah, it IS confusing. Probably better discussed over a cold beer.

Think this way:
DV signal is 0 IRE to 100 IRE
DV color space is 16 RGB to 235 RGB.

Analog signal is 7.5 IRE to 100 IRE
Analog colorspace is 0 RGB to 255 RGB (that's why you'll see 110 IRE on a waveform scope.

I'm assuming that it isn't doing this for a PAL project since I've
got below 16 values and they are pitch black.

Beer. . .but I'm a nerd. . .I don't even drink. . .


When you "NTSC system," in reference to black being something other than 16 if not properly set up, what do you refer to? The camera? The NLE? I thought the NLE just took in whatever the camera gave it? There's no way to set up anything during capture, like there is with AVID (or at least the Avid I used--you could pump up brightness, audio, whatever before you captured). I don't have a DV deck or anything.

Josh...

just what you've been thru. if you do everything right, for example, but feed a 0 IRE pedestal to your NTSC monitor(which is expecting a 7.5 IRE pedestal), you won't see the right color blacks. There's a zillion ways to mess this pedestal thing up, just in POST, alone.

here's a little lab exercise that demonstrates a LOT about your NLE and display monitor.

Download a black step wedge off the internet, use the step wedge provided as "generated media" in Vegas 4, or better yet, make your own black step wedge in Photoshop. Be sure to start at RGB 0,0,0 and makes wedges all the way up to RGB 255,255,255. Be sure to include a wedge at 16 and a wedge at 235.

Now, import this step wedge into vegas 4, turn on the waveform monitor, insert a Broadcast Color filter on the clip and play with the settings. Be sure to always have the checkboxes set in the waveform monitor match the settings in the Broadcast filter, otherwise the waveform you're looking at means nothing. Also, compare the white and black wedges to what you see on the monitor to what you see on a CRT screen. You'll learn a lot.

Just had an exhaustive talk with a friend of mine who owns a rental house and functions as a video engineer on the sets of some its clients.

He told me basically that 1) once the product leaves my hands, there's a million ways it can go wrong until it's broadcast

and 2), the change between 0 and 7.5 when going from digital to analog is AUTOMATIC, that is, black levels are automatically raised up to 7.5 from 0, or an additional 7.5 units (?) from whereever they are. Messing with them in post, then, is a bad idea because it'll result in an additional 7.5 bump from whereever I've raised them to. Basically then, if shoot at 0, edit at 0, and output the same way, keeping my deepest blacks above 0, then I'll be okay, provided there are color bars from which to set up. Since the NLE I have generates them, should be no problem.

wrong...sometimes right...but, mostly wrong. If you follow this policy, all I can say is BE SURE to label your final tape as to what the setup level is.

But wait. . .if I've been setting my black pedestal on the camera recently to -2, then I AM using a 7.5 pedestal, no? All the way to the left would be 0, right? So then I should set the monitor to 7.5 too?

and 2), the change between 0 and 7.5 when going from digital to analog is AUTOMATIC, that is, black levels are automatically raised up to 7.5 from 0, or an additional 7.5 units (?) from whereever they are. Messing with them in post, then, is a bad idea because it'll result in an additional 7.5 bump from whereever I've raised them to. Basically then, if shoot at 0, edit at 0, and output the same way, keeping my deepest blacks above 0, then I'll be okay, provided there are color bars from which to set up. Since the NLE I have generates them, should be no problem.
Consumer equipment doesn't do that when converting from DV --> analog. It's supposed to. You can compensate, but then you'll make out of spec DV that would be too bright with equipment that does things right.

i have made a few TEST making a VCD.
which may or may not explain if you need to set DVD player to set up or to 0 blacks?

using vegas codec to create the mpeg 1 VCD . the black level is correct with DVD player to add black set up..

using the microsoft DV codec to create the mpeg 1 VCD. the black levek looks correct with DVD black level at it's default ( no set up).

the DV codec's are only used to decompress the avi files then the mpeg1 codec compresses them to mpeg 1 BUT it appears that just the uncompressing sets up the black levels ??

dropping both clips into Vegas TL the mpeg created using msDV codec has the blacker black .. using the waveform 0-255 scale the msdv mpeg has a 0ire black .. the vegas mpeg has 6 ire black .. changing scale to 16-235 the msDv mpeg has a -7 ire black .. the vegas mpeg -1 black.

my guess is that the same might be true when creating a mpeg2 for DVD ... which might result in a mpeg 2 using Vegas codec to decompress might set the black level so you need set up on the DVD palyer ? .. using the msDV codec in Vegas might set the black levels that the DVD player needs to be set to 0 black level .

Went to the Adam Wilt article dealing with this, and read:

Some DV and DVCAM camcorders like the AG-DVX100, DSR-PD150, DSR-250 can record a video signal with "7.5% setup." Is that OK?
The AG-DVX100, PD150 and DSR-250 have a "7.5% setup" setting in the menu. Don't use it! It does not add setup to the analog outputs; it modifies the digital data coming from the camera head by boosting the black level, resulting in washed-out blacks, reduced precision, and nonstandard tapes as described above. As a result the analog video played back from the camcorder or viewed live has its blacks at 7.5 IRE, so the signal looks like it has setup, but what it really has is a too-high black level!

He didn't mention the XL1s, but as it has an adjustable pedestal, that's essentially the same thing, no?

Am I to understand that unless the setup slider is ALL the way left, I'm shooting weird non-standard video, and also cheating myself out of an additional range of constrast?

I think that's completely true Josh.

You also need to remember that some codecs behave differently from others. Some assume that 7.5 has been added and will actually expand the color range for display. Others just leave everything alone. You will definitely get different result is you use the MSDV codec as compared to the Sony codec.

There's been a HUGE discussion here:

http://mediasoftware.sonypictures.com/forums/ShowMessage.asp?MessageID=247747&Replies=101

Josh...

If I understand what Rob Lohman said earlier in this thread, the XL1s pedestal setting doesn't really affect the DV spec requirement of 0 IRE, all blacks will always be written to tape as 0 IRE. What the on cam pedestal slider does is affect the way the RGB color space is mapped to IRE signal. If the slider is all the way to the left, you will map pure black to 0 RGB. As you move the slider to the right, you will map pure black to higher RGB values. The DV spec is for pure black to be at 16 RGB. The slider allows you to set pure black at 0 RGB. This produces blacker blacks, but, it's also a non-standard setup for Lab color. I'm not sure of the implication of this, but,if you set the 16-235 Lab Color checkbox in Vegas 4, it will remap balcks to 16 RGB anyway.