How to adjust levels in a portion of a clip?

Gene Aum wrote on 11/3/2012, 12:18 AM

What's the best method to lighten the speaker portion of a clip in a 'lecture-with-projection' event video? I've tried masking but was unsuccessful - or perhaps wasn't doing it correctly. (VP 11)

I record events in different conference rooms around campus in which I have limited control over house lighting which provides sub-optimal presenter lighting in most situations. The speaker is usually quite dark due to the camera reacting to the projected video screen's brightness.

I can't use the slides overlays as the speakers frequently move in front of the projected video in order to refer to content on the slides.

Is masking the correct tool to use, or some other?

Thanks, Steve


set wrote on 11/3/2012, 12:22 AM
How about using 'Fill Light' filter? or curve but brightening the dark areas only?
Serena wrote on 11/3/2012, 3:49 AM
Masking will give you most control. How did you go about that?
Grazie wrote on 11/3/2012, 4:52 AM
I've used the Bump Map. Just use the Spotlight>Directional itself, none of the other controls. I've gotten a nice "natural" feel to the video. I've even used this to great effect on natural external shoots. Used sparingly it can act as a well placed reflector!


Tim20 wrote on 11/3/2012, 6:53 AM
Mask them out duplicate to new track and brighten there composting the two back together and feather as required to get a smooth blend.

Note: one mask will be an add the other with be a subtract.

Just realized I may be using After Effects terms for mask. Positive and negative in Vegas.
farss wrote on 11/3/2012, 7:33 AM
I've tried all these techniques over the years and none of them yield good results and as the speaker movse around involve a lot of manual keyframing.

Mostly today I wouldn't worry about it, does the viewer / client care would be my first thing to consider. If they really do, if they want it to all look professional then step one is professional staging of the event and a setup that requires the presenter to walk in front of a projection screen to point out something isn't professional. Things just go downhill from there, it's in the same league as letting the presenter walk in front of the speakers to deafen the audience with feedback.

I used to give presntations / training in a room with a projector and put my hand in my pocket and for under $50 bought a wirelss "mouse" gadget that let me control the PPT presentation from anywhere in the room. Same gizmo included a laser pointer. For much less there's those telescoping fit in your pocket, same size as a pen, foldup physical pointers.

Tim20 wrote on 11/3/2012, 8:08 AM
Well I would do something like that in AE, make a mask vignette around the speaker motion track and be done with it.
rs170a wrote on 11/3/2012, 8:14 AM
I agree with Bob. I've shot a number of these lately and expose for the presenter.
I get a copy of the presentation and drop the slides in at the appropriate times in post.
No one has ever complained.

fldave wrote on 11/3/2012, 8:41 AM
Maybe a luminance mask that isolates the dark parts, then use levels to lighten those areas?
Grazie wrote on 11/3/2012, 8:46 AM
I've had front of house re-relocate the podium/stage because the lights which were promised to be illuminating the Speaker weren't, and the lighting jib was 28' above the audience. But nobody had asked for the Tower to be left.

Better to get these things done before. But, once in this position, do something else. Bob, Mike 20-20 is great. Can you tell me where I can get a To-Go Pack of this stuff?

For me, I was asked back to conclude the next Seminars, asked what in future the approach should be and advise on their approach and produce a Promo for the organisation.

My approach? Always turn a lemon into lemonade.

Tim L wrote on 11/3/2012, 9:17 AM
I'm an amateur and have no experience with this, but is the camera locked down? If so, the screen would be fixed in the shot and it would be easier to mask the screen.

A simplistic approach which might involve very little extra effort in post would be:
- start with duplicate tracks
- on the top track, mask and keep the screen, use color curves to adjust exposure
- on the bottom track, use color curves to adjust exposure of the rest of the room

I am convinced that this would not produce as good of a result as the other suggestions, especially suggestions to use a (keyframed) mask around the speaker to mimic a spotlight. It all depends on how much time you have to spend on the project, and how professional the results need to be. It might be worth a quick try.
farss wrote on 11/3/2012, 9:39 AM
"Bob, Mike 20-20 is great"

Sure, of course.
Reading the OPs post though this very much seems a regular job:

"I record events in different conference rooms around campus in which I have limited control over house lighting which provides sub-optimal presenter lighting in most situations."

The capital costs of fixing the problem at the source will:

a) be recovered in the money spent fixing it in post very quickly
b) provide a better outcome than can be achieved fixing it in post.
c) time is of the essence for a lot of these things. Futzing around in post takes time as well as money.

I appreciate as well as anyone this isn't easy but unless we make our voices heard we'll be forever spending hours needlessly and most probably not even paid for "fixing it in post". I'll say again, there will be times when it just happens and that is acceptable, it should not be happening as the normal course of production in a regular job in the same venues.

Grazie wrote on 11/3/2012, 10:24 AM
I also read it and it was this: "in which I have limited control over house lighting which provides sub-optimal presenter lighting in most situations."

Well then, Bob, what you might suggest is that he gets some control! That's it, get control. And, if he can't, what can he do? Hm?


rs170a wrote on 11/3/2012, 11:29 AM
Most of the PowerPoint presentations I record are with teachers (rank amateurs at it) at the college I work for and are often in classrooms with very little control over anything :(
That's why I do what I do which is expose for the presenter and drop the images in afterward.
It may not be good TV but it works for me and they understand why I have to do what I do.

JackW wrote on 11/3/2012, 2:10 PM
I often shoot in hospitals, where the presenter is a doctor or nursing supervisor and the on-screen material is complex medical imagery. The presenters use laser or light pointers, which rules out dropping in PowerPoint material at a later date. My solution is to use two cameras, one locked down on the screen, the other on the speaker. Cutting from one to the other in post is quick and easy, and enables viewers to see precisely what's being pointed to on screen. It also allows for putting the presenter on-screen with the slide in a picture in picture window when desirable.

farss wrote on 11/3/2012, 4:57 PM
"That's it, get control."

That would be good but unlikley to happen because I'd imagine that's another departments problem. So he has to escalate or shift the problem to the facilities or building services or whatever it's called, department.

" And, if he can't, what can he do?"

Not much but having made the case for whatever needs to be done to whoever has control over the source of the problem he has "plausible deniability".

In the end it's about managing the clients / boss's expectations.
Once we start fixing things, oftenly for free, there's a considerable risk attached. The job is delayed, and then there's the expectation that we'll keep doing it. Been there, done that. We may well be fixing things no one cares about. You think you're being generous and a good person and then you loose the client to someone who delivers it next day, looking like s-h-i-t-e because all the client really wanted was something done quick, dirty and cheap.

Gene Aum wrote on 11/3/2012, 5:22 PM
Thanks to all for your input and suggestions - some of which may work, and some perhaps not. Definitely will retry the masking options some of you suggested.

The overlays for my videos would be too distracting as the presenters constantly move to and from the podium into the projected video. I'd have to keep cutting between the real video and the slides.

I was reading last night re the color temperatures of projection video and artificial lighting. Projectors are purportedly natural-light 5600k, and stage lighting is ~~ 3200k. No wonder the cameras are not handling it well (and adjustments of WB, gain, etc. barely make a diff).

Of three cameras I used on a job yesterday (two prosumer, and my old Sony FX1), the old Sony looked the worse.

To farss: well no, I've never had a user complain about the presenter being barely visible, but, I'm not happy with these results. AND, the campus TV station (which is over-the-air, and cable) want my videos for their programming, yikes!

I just had an idea of where to add additional lighting: under a 'ridge' on top of the podium. They would 'up-illuminate' the presenter, but the cameras would not see the light source. The lights would have to be soft-ish and not distracting to the presenter, yet provide 5600k light so as to match the projected video.

If anyone knows of product, or has tried this technique, please let us know.

Thanks for all the amazing replies!

PS: I'm surprised no one commented about the recent Vegas webinar where Gary R. was asked to demo the 'improved' VP12 color matching. It appeared to me that the feature was about the same as VP11.
Stringer wrote on 11/3/2012, 7:09 PM

This Sony Webinar covers one way to do what you are asking about..

Relevant info starts about 16 minutes in ..

farss wrote on 11/3/2012, 8:36 PM
"I was reading last night re the color temperatures of projection video and artificial lighting. Projectors are purportedly natural-light 5600k, and stage lighting is ~~ 3200k. No wonder the cameras are not handling it well (and adjustments of WB, gain, etc. barely make a diff)."

Most projectors use HID lamps, they can run to more like 7,000K but 5,600K is close enough. Tungsten stage lighting is 3,200K or the modern stuff (LED, HMI etc) is mostly more or less 5,600K. Your camera will work better with 5,600K lighting.

The problem with putting more light on the presenter in front of the screen is not getting any of that light on the screen itself. Take a look at how TED has things setup, think about the budgets they have. They've been here in Sydney and there was a considerable crew with a couple of trucks involved.

You can put light just in front of the screen, it can be done but it's probably going to make the people look pretty bad with very deep shadows unless you have very powerful projectors which are expensive to buy and expensive to run in lamp costs which woud let you get away with some spill from softer lighting. Really way better to explore ways to avoid having the presenters walk in front of the screen. I used to do a gig once a year where we had the screen in the middle with stingers (drapes) to stop any spill from my lights which were also balanced to 5,600K. The lecturn and table for group discussions were well off to the sides of the stage area. All worked pretty well.

That gig was about 8 hours of video for the day, trust me no way I was going to futz around fixing things in post.

Gene Aum wrote on 11/3/2012, 9:54 PM
Stringer: Thanks, using the bezier will be a great workaround until I can get the lighting solved.

Bob (farss), I'm sure there are number of issues you raised that are plaguing my shooting environments. I had cranked up the overhead stage lights to lighten the speaker, but as you said that also splashed a greater amount of 3200k onto the screen (and into the cameras).

As an author in a book on lighting pointed out: Conference rooms are build by architects, which don't have any understanding of lighting for video.

I have an external LED light (meant for shoe-mount) that would get more 5600k into the light-mix, but it may be too harsh for the presenter.

Yes, post-fixing is taking too much time. Need to resolve in pre.

Hmmm, will have to look for 5600k overhead stage lights, at least for my conf. rooms. I'm SOL wrt the other facilities on campus.
set wrote on 11/3/2012, 10:26 PM
"If it can be done during shooting..., better fix it during shooting..."

--- Sometimes it is easy to say 'it can be done during post', yet also frustrating during post.

But, I once got into situation of cannot control the lighting and require to fix them during post... DeNoising due to gain-noise/high-iso.., color balancing - due to extreme blue ligthing - bad lighting position but not-permitted to add additional lighting, Stabilizing footages..., CRAZY... 8 clients - 8 months in total to finish them all.... What an extreme-hot Post Production H*** !
ah--thank goodness now I have made it through them all successfully...
nedski wrote on 11/4/2012, 1:21 AM
@ Gene Aum

For about three years I recorded lectures at a local observatory. I tried masking the presenter and playing with the levels in Vegas. The noise in the masked portion never looked good.

The solution that worked the best for me was to use two 3W LED spotlight bulbs with square, homemade snoots made from black foam core. The total cost was under twenty dollars each. I hung the lights from the eight foot high drop ceiling. One light was pointed at the lecturer straight on, the other was on the right side, at maybe a 45 degree angle. The light at 45 degrees was to illuminate the lecturers face when they turned towards the screen. The snoots would limit the light spill on the screen. The lights were about eight to ten feet from the presenter. The room was dark except for the light from the screen and recessed red lights in the ceiling.

The lecturers were literally right next to the screen and most of them would, as you've mentioned with your presenters, physically interact with the screen by touching the screen with their hands or using laser pointers.

Since you move around to different rooms, I'd suggest that you mount the lights on inexpensive, black colored, light stands and put them between the presenter and the first row on the audience.

Here is an example of one of the lectures. I also used two cameras in the example.

I did use the method of adding their PowerPoint presentation once in a while. It was extremely tedious to time their slide changes. Check out this lecture. I didn't use the LED lights for this one since it was in a large auditorium and I had a very cooperative lighting person!

I also would use a wireless lavalier mic.

Good Luck!