Waveform captures! Explain to me...

petelms

petelms

Well-known member
Hi!

Please, could someone explain to me briefly about these waveform captures...? I´m using PAL.

1.) If I have understood it right, the green color is telling me the brightness of the image, right? And the blue color is telling something about the colors?

2.) So, the this image is too bright right? Should the green color be under 1.0 always in PAL? How about the blue "chroma" color? What are the limits for that? What are the low limits? What is too low?

3.) Does the green and blue lines on the right tell me the actual limits?

4.) Anything else important that I should know about these?

Thank you and here are the captures: :dankk2:

2vsrw95.jpg


2ivxs75.jpg
 
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Pete, can you throw up a stillframe of the actual video for this moment too?
Belive it or not, but scopes are best read with the context of the actual image alongside.

- Mikko
 
from my understanding of it, it appears there are certain areas in that frame that are over 100 IRE NTSC safe is 100 and below. this means that there could be potential problems when viewing this frame on regular NTSC televisions. not sure how PAL works in this case however
 
Sure here are the frame caps from the all three cameras...what should be done to these (this is a wanna-be football studio)?
 
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These waveform grabs above are form the wide-camera, right? You can see on the scopes where the people's faces and the ball blow out and hit the white clipping level at 1.0V

You need to drop the intensitiy of you key and back lights (fill is fine) a little bit so that the highlights come below about 0.9V Then it wil look much better.

- Mikko
 
Yes, the waveform caps were from wide cam. Yes, it should have been done right when shooting but now it's too late, hehe.
 
Unfortunatly once the picture is clipped (be it over or under exposed), there is very little that can be done in post. You can use the "Proc amp" settings in Premiere to fix up your basic levels a little, and then use the other color correction tools, like "Curves" to see what you can do to the image. You need to drop down those highlights a little.

Sorry to use you as an example, but (unfortunatly) here's a classic example of how it is going to be very difficult to "Fix it in post" 2 extra min on set can save hours in post.

- Mikko
 
If only I would have knows about those waveform-monitors then, heh, and understood about them something. :beer: Next time I know, this was a good lesson to learn. :beer:
 
The frame grabs don't look bad at all. The hihglights that are blown out are not in any area that is important. Yo can lower your hihglights in post a little if you want but I think it only neccesary to clip you highlights so that nothin unexpected happens when played back on a non professional CRT. just becasue it is over 1 doesn't mean the detail is lost. most of the deatil is stored in the hihglights in fact.
 
The two shot (wide) appears to be exposed differently than the singles, the key looks to be almost a full stop over, so I would just use the two shot as sparingly as possible in the cut.
 
Thanks, guys. No, the background was not meant to be keyed out...heh, it surely looks like it because it is some kind of a green screen actually...but that was the only background we had in that place, so we had to use it. :beer: I should have put some more light also to the background...
 
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petelms said:
2.) How about the blue "chroma" color? What are the limits for that? What are the low limits? What is too low?

3.) Does the green and blue lines on the right tell me the actual limits?

2vsrw95.jpg
Click to expand...

Nobody replies to this issue :(

I've been wondering about this too, if you lower the chroma with saturation, the effect is too heavy, if you're supposed to get the chroma signal between 0,3 and 1.0. Theres no way of controlling chroma while shooting (without a waveform) is there, or seeing how high its going. I'm also wondering why chroma is going below 0,3 (black)...

I believe the lines on the right tell you where the signal is going. I always use intensity 100. Any problems with that?
 
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