changing the black default background in Vega

farss wrote on 7/4/2006, 7:41 AM

Sorry that's it.

I'd normally set it to black at 16,16,16 though, just so fades to black don't go below legal if that worries you.

Bob.

Bansaw wrote on 7/4/2006, 8:06 AM

Thanks,,,, what do you mean by "legal" ?

Chienworks wrote on 7/4/2006, 8:09 AM

Digital video uses RGB values from 0 for black to 255 for white. Broadcast TV only accepts 16 as the darkest value and 239 as the brightest. Anything ouside this range can cause reception problems on TVs. Broadcast legal is 16,16,16 through 239,239,239. Anything outside this range is "illegal" for broadcast.

If you're just making stuff for yourself then 0 to 255 is probably fine. Most DVD players and relatively modern TV sets won't care at all. The picture may look a bit more contrasty than your audience is used to though.

TheHappyFriar wrote on 7/4/2006, 8:14 AM

does it even matter if anything is "legal" anymore? All broadcasts are digital (or will be), people are buying more digital TV's that accept the whole range. DVD players auto-convert I belive (maybe?).

just wondering. I understand that someone with a 1970/80/90's TV will go all wacky with bright whites but is that even the case anymore? I know my Monitor I used for a TV doesn't care, so I'm always cautious, but I've never had any buzzing when I've tested my DVD's on TV's bought within the past several years.

Bansaw wrote on 7/4/2006, 8:22 AM

Thanks, however, I am still wondering how to change it from black to white...
There must be a setting somewhere but I can't find it.

Any ideas?

fwtep wrote on 7/4/2006, 9:01 AM

For personal use it doesn't really matter if the levels aren't legal, but --in the U.S. anyway-- distributors (broadcast, home video , etc.) still require it.

I'm sure it'll change eventually and black will be the new black. :-)

Chienworks wrote on 7/4/2006, 9:28 AM

Dunno about you, but almost everyone i know is still watching analog broadcasts on analog sets, including yours truly. Come to think of it, i can't recall the last time i went into someone's home and saw digital TV equipment.

Some of the locally-bred late-night commercials are obviously going outside the legal range and my screen just goes crazy. Titles especially are a problem because, even if the original video isn't altered, lots of these home-brew producers use 255 white for the title. In many cases it's bad enough to cause the picture to unsync and for the audio to distort. In some cases it even knocks my cable modem offline!

Jay-Hancock wrote on 7/4/2006, 10:14 AM

Bansaw - as Farss said, there is no way to set a property or toggle a setting and make Vegas change the background to white. Best way I know of to achieve this is to add a bottom (video) track to your project. On this track, drop in a Generated media with solid color as white. Your white should be RGB 235,235,235. Unless it would only be viewed on a PC, then white would be RGB 255,255,255.

The Digital 601 spec says luminance of white is Y=235, not 239. (technical discussion). Probably most TV's wouldn't care about this minor distinction (235 vs. 239), though. But you should avoid 255 if your target is not for a PC (only).

I have a Mitsubishi high-def RPTV that I purchased in 2000 and it goes crazy if it gets illegal blacks. Loses sync, causing the picture to tear and roll. Lots of people with Mitsubishi high-def RPTVs have the same problem (as noted on IO Data's forum for their high-def LinkPlayer 2). Probably a few other TV brands have this problem, and lots or most don't care.

The topic of using broadcast colors is pretty current on this forum. Here are some other posts about it:

Broadcast colors: is it always necessary?
Accuracy of Bars for HD alignment

GlennChan wrote on 7/4/2006, 1:22 PM

Legal colors could mean one or two things:
A- Making sure your colors aren't getting clipped. By extension, you'd also care about the opposite/sister problem (levels being converted incorrectly).
B- Broadcast legal... transmission imposes additional limitations on what signals can be broadcasted. These signals will usually be clipped before transmission.

If you're not doing work for broadcast, then B shouldn't matter. However, A does matter. With Vegas, there are some situations where your levels will get converted incorrectly. In the following discussion, legal will just be in the context of A.

Some background:
There are three general color spaces that apply to Vegas:
1- Y'CbCr color space.
This is the form DVD and DV video are stored in. The legal range for Y' are 16-235, with the other values being used for over/undershoot of the signal.
By legal range, I mean that the blackest black is at 16 and the whitest white is at 235.

Vegas, like most computer applications, (incorrectly) label this as YUV.

2- Computer RGB
RGB color, where the legal range is from 0-255.

3- Studio RGB
Also RGB color, where the legal range is from 16-235.

Vegas processes everything in RGB, so Y'CbCr video has to be converted to RGB for processing. The default Sony Vegas DV codec (Vegas 5+) converts Y'CbCr video to studio RGB form. Most other DV codecs convert to computer RGB instead.

The MPEG2 encoder that comes with Vegas+DVD expects studio RGB, NOT computer RGB. So you can get wrong colors this way.

There are some other combinations where you can get incorrect levels... because the encoders and decoders can't tell if the RGB video is studio RGB or computer RGB (and will accept either).

Vegas is a little silly in that most filters + generators assume computer RGB color, even though its default DV and MPEG2 codecs assume studio RGB color. i.e. if you want to make a DVD with legal levels, the fades to black (*by default*) will fade to 0 0 0 RGB instead of 16 16 16 RGB.
The remedy to this is to add a solid color media generator of the color 16 16 16 RGB.

In other cases, you should manually 'wrangle' all your images such that they all get into one color space (i.e. studio RGB), and convert to the other color space if necessary.

farss wrote on 7/4/2006, 2:05 PM

Possibly really silly question here but why do you want the background white?
I only ask because that does seem an odd thing to need and most of the other replies might be addressing a similar but different issue.
In the end you can use generated media to make the background any color you want (all fades go to red, anyone?).

You see all video tracks in Vegas are composited, 1 track with nothing under it is being composited to nothing (absolute black).

Bob.

Bansaw wrote on 7/5/2006, 3:19 AM

I have a logo on a white background I am spinning in at the start.
It doesn't look right on a black background. I have found a way of inserting another video track and just having that white.
So, I have a white background finally.

rs170a wrote on 7/5/2006, 3:40 AM

I have found a way of inserting another video track...

Insert - Video Track (or CTRL+Shift+Q or right-click in the existing video track header and select Insert Video Track) usually works for me.

However, there's no need to insert a separate white video track.
#1. Drag your logo on to the timeline. Drag to desired length.
#2. Media Generators tab - Solid Color - White. Drag this to the track B>below your logo. Make sure to set the white levels to 235-235-235. Set length to match logo timing.
Spin away :-)

Mike

DrLumen wrote on 7/5/2006, 5:44 PM

Wouldn't fade to color be the same thing as setting a background color (track envelope> fade to color)?

DrLumen wrote on 7/5/2006, 6:01 PM

Nevermind. I just saw what effect that had.