PAL DV/HDV legal levels: definitive answer please

TLF wrote on 4/5/2009, 2:38 AM
Can someone please give me a definitive answer? I'm Working with Vegas 8.0c, using a mix of PAL DV (from a Canon MVX40) and HDV (from Canon HV20 and Sony FX1E). All I need to know is: to ensure I stick with within the legal limits for PAL, should I apply the Computer RGB to Studio RGB filter?

Looking at the waveform scope set to display Studio RGB with no 7.5 IRE, the luminance peaks at 110%. Applying the Computer RGB to Studio RGB filter reduces the peaks at 100%, but the the colour on the preview becomes insipid (I guess it will display correctly on a television).

I have searched for answers, but they become complicated by posters wishing to squeeze every last detail out of the (HDV) signal.

Your answers may lead me to ask other questions...

TLF

Comments

LarsHD wrote on 4/5/2009, 3:08 AM
Many of the major european broadcasters have PDF documents describing their requirements for what they see as acceptable standards of productions. Like the BBC, The Swedish Broadcasting Corporation etc. have very detailed documentation available on the web. Maybe this could be someting?

Lars
farss wrote on 4/5/2009, 3:21 AM
Both DV and HDV cameras record video that's StudioRGB.
Both are quite likely to have some to a lot of overshoot.
Do not use a StudioRGB to ComputerRGB transform, you will fry get your blacks way too grey.

It's really up to you to decide what you do with those 'overshoots'.
You can use the Broadcast Colors FX to simply clip them, you can adjust that FX to not clip them so hard or you can use a Color Curve to roll them off or even remap the whole curve into the legal range. Glenn has a sample project somewhere that I cannot find the link to that provides presets for doing all this with the Color Curves.

PS, it's very unlikely that you should ever tick the 7.5 Setup box in the scopes. There used to be some A/D converters that did not do the Setup thing but I think they're long gone.

Bob.

EDIT: Look in the article here around half way down the page for the like to the sample project under "The Curves Method of Colour Correction"
GlennChan wrote on 4/5/2009, 11:30 AM
Simple answer:
- stay in a 8-bit project
- follow the instructions mentioned in the tutorial bob linked to.
- If it is going to a broadcaster, apply the Broadcast Colors filter. De-select the 7.5 setup box since your country's standard is likely analog blacks at 0 IRE (there are exceptions for certain PAL countries). Check the studio RGB box.

Long answer:
http://www.glennchan.info/articles/vegas/v8color/v8color.htm

Both DV and HDV cameras record video that's StudioRGB.
But they... don't. They record Y'CbCr values. Whether the Y'CbCr values get converted into studio RGB or computer RGB depends on the codec (and whether the Vegas project is 8 or 32 bit).
farss wrote on 4/5/2009, 2:06 PM
"Both DV and HDV cameras record video that's StudioRGB.

You know that, I know that.
I chose not to say that because in the context of the question TLF asked he does not NEED to know that. Worse, it only serves to confuse people.

There's an old saying "Those who can, do. Those who can't teach"
I've always taken that to mean "Those who can shouldn't teach."
There's some exceptions obviously, I've had the privilege of listening to a few of them but they are rare.


De-select the 7.5 setup box since your country's standard is likely analog blacks at 0 IRE (there are exceptions for certain PAL countries). "

Again confusing to anyone who doesn't understand the context. We're talking about DIGITAL video. What the broadcasters kit decodes to on the analogue side (if they still have one which is very unlikely) is irrelevant.


Bob.
GlennChan wrote on 4/5/2009, 4:59 PM
re: DV / HDV / Y'CbCr / studioRGB
Where I'm coming from: saying that DV decodes to studio RGB is confusing because it is not always true. e.g. if you use a 3rd party DV codec, or if you are in a 32-bit project.

Anyways, I suppose the distinction is clear now.

Again confusing to anyone who doesn't understand the context. We're talking about DIGITAL video. What the broadcasters kit decodes to on the analogue side (if they still have one which is very unlikely) is irrelevant.
It's unclear what type of delivery the original poster is targeting.

But for broadcast, if you are sending a digital master, you often do need to make sure that the analog levels (once it gets converted from digital->analog) can be broadcasted over the air. And even with digital transmission, a lot of times the signal will get converted to analog / composite NTSC or PAL... so it needs to be broadcast safe anyways.

Anyways, that's why there is the qualification, if it is going to a broadcaster.

Cheers.
TLF wrote on 4/6/2009, 12:40 AM
Thanks Bob and Glen.

I appreciate that it's difficult to answer when the questioner doesn't know how to phrase the question in order to elicit the correct response.

And sometimes a straight answer is impossible without being misleading.

My question was based on the assumption that I would be using Vegas with no 3rd party codecs. Vegas would decode and encode the footage (DV + HDV --> DVD MPEG).

However, I do plan to meddle with frameserving to 3rd party codecs, so your links to Glen's articles have saved me having to embarrass myself further with additional questions.

Thanks again,

TLF