thanks bob, knew i could depend on you - but i posted here in case anybody else has the same question / thought....

that said, i'm never going to have control over lcd's outside of my living room (well, maybe a couple of friends ;-)), and added to that, i have no idea if people getting a dvd with (a clearly labelled) hd file on it are going to watch the dvd on their pc or tv.

this sorta rules out having two versions, ie, sudio dvd, pc rgb.

i'm tempted to do the whole edit as normal (studio), then check finished in both studio then computer on all available pc, lcd, crt screens... then release the dvd version in whatever looks best... that said though, i have a feeling it's going to be seen on lcd's more than anything.

finally, for projection, i presume i should go with computer rgb?

thanks again,

leslie

yes. in fact, I think the studio setting is only really useful for CRT's. I've never had any issues using computer RPG video on LCD's (TV or monitor), projectors, and my CRT tv/monitor.

a badly adjusted anything will always yield bad results. IE if the preset on a projector is set for "presentation" then a video will look pretty yuk.

i agree hf, never had any problem playing RPG on lcd's ;-)

so, in your experience, you burn dvd's that are computer rgb'd rather than studio?

thanks

leslie

i don't normally convert to studio at all. I let things alone. I do CGI (from games, 3d, 2d) on to DVD & DV/HDV. Always looks good. When everyone I knew had CRT TV's (I have an old NEC monitor next to me that I preview on, must not care about using computer RGB as there's no issues) I would put things legal, but everyone I know has LCD TV's or projectors so i stopped worrying.

I don't think there's a dvd player on the planet that will output an out-of-bounds signal to a tv or monitor, regardless of the levels in the file. Doing so would place a huge risk on player manufacturers, even though the sets have AGC to handle overloads.

That being said, if you don't want your video highlights bumping up against the player's limiting circuitry, it's probably a good idea to keep it close to "legal." I doubt computer rgb would create much of a practical problem.

"yes. in fact, I think the studio setting is only really useful for CRT's."

My impression has been that it's mainly for analog broadcasts (and they are almost gone). Unconstrained highlights would exceed the RF bandwidth, blowing out the whites on the screen, and splattering all over the audio carrier frequency, causing the most obnoxious buzzing sound. Like with some older Nintendo toys that used those really crappy RF modulators.

My impression has been that it's mainly for analog broadcasts (and they are almost gone). Unconstrained highlights would exceed the RF bandwidth, blowing out the whites on the screen, and splattering all over the audio carrier frequency, causing the most obnoxious buzzing sound. Like with some older Nintendo toys that used those really crappy RF modulators.

Very true, but this is only a part of the potential problems - the other being lost detail in the clipped super-whites or -blacks.

That said, I never really saw a DVD/BD player / (HD)TV combination that would do it to my DVD/BD's even if I didn't care to apply the "broadcast safe" FX (or adjust levels manually). However, in commercial DVD's I'll always do it...

Me thinks we need to be a little careful with our use of the terms Computer and Studio RGB here.

Depending on how you use some of the HDV / XDCAM cameras the Y' values go from 16 to 255. That's neither computer or studio RGB.

If you encode that directly to mpeg-2 and make a DVD it'll probably be OK on both a CRT and a PC's LCD as the worst that can happen is the player clamps the whites to 235. i.e. you loose a bit of detail in the highlights.

If you use an FX to do a Studio to Computer conversion the blacks will be correct for computerRGB but the highlights will be toasted a bit more than you might like. That's why I watch the scopes and get things lined up to a standard and then convert from that.

Bob.

Thanks for confirming some of my impressions.

Out of curiousity, I just checked almost 5 hours of source footage from two (XLH-1) cameras, and our paid shooter had kept everything easily within 16-235 save for a few specular jewelry reflections. Kind of nice when you don't have to worry about it from the get-go.

As an experiment, I applied Studio->Computer RGB to a well-lit scene from the same shoot, made a dvd, and it plays just fine on anything I throw it at. If there is any additional highlight compression taking place, I am at a loss to detect it.

If you encode that directly to mpeg-2 and make a DVD it'll probably be OK on both a CRT and a PC's LCD as the worst that can happen is the player clamps the whites to 235. i.e. you loose a bit of detail in the highlights.

wondering out loud.... do DVD players auto-fix to studio RGB like they auto-take care of interlacing progressive footage for interlaced tv's & auto-convert 24fps to 30fps for NTSC tv's?

You either convert or do nothing depending on what the encoding codec expects. It's as simple as that as far as the levels conversions go.
http://www.glennchan.info/articles/vegas/colorspaces/colorspaces.html

2- Yes, cameras will record illegal values. The right thing to do is to clip them off. This way your material will look consistent from TV to TV (e.g. because CRTs are capable of showing these illegal values, while I don't think LCD TVs will do it). In signal processing down the chain, these illegal values may or may not be clipped (either can happen). If you don't have these illegal values in the first place then you wouldn't need to worry about this.

If you want to recover additional highlight detail then you can map those values into the legal range.
See the first link and/or this article:
http://www.glennchan.info/articles/vegas/color-correction/tutorial.htm

Those are some great info pages and tutorials, Glenn, thanks! :)

One question though, for making Blu-ray discs, those would also use Studio RGB, correct?

Thanks.

now glenn, if i'd been a good boy and read your pages BEFORE posting, this thread would have never come into existence!!!

thanks for a clear, concise and easily understood explanation.....

leslie

So bluray would be mpeg2 or mpeg4... can't remember. But in Vegas, the default mpeg2 and mpeg4 codecs, from what I remember, behave the same.
In 8-bit, they expect studio RGB levels.
In 32-bit projects, they expect computer RGB levels.



Heh...