Need a clever solution to this problem

Posted by Dan Brockett 
Need a clever solution to this problem
March 07, 2009 07:15PM

I am editing a show, shot on the DVX100A. Footage is mostly interview footage. Shot was lit correctly, exposure is good, all is well. The talent was shot against a black BG and is wearing a black jacket. The DP lit it well, there is a rim/hairlight so talent and shoulders stand out against BG pretty well but it is still a black jacket.

The only problem is that this footage will be projected on a crappy low end projector in a not too dark room. While the shot looks fine on my BVM edit bay monitor, client is worried that once the sequence is projected on this lousy projector, much of the time in rooms that have too much ambient light for proper projection, that this person will have the floating head effect, where you will see the person's face and shirt fine, but where the black jacket is will basically just be seen as pure black on black with no separation. I can see their point, if I squint and look at the monitor with a lot of ambient light on it, it could appear to be a flaoting talking head.

Of course when I just up the levels and gamma, it begins to blow out the face to raise the jacket levels up so that the jacket appears to be dark gray rather than black. We are now trying the keyer and are able to pull a luma key on the jacket and then composite the key back in with the regular shot using an "add" composite. All is well and it looks good when parked on a still frame. Problem is, when you run the video then, this has composite has increased the noise level on the jacket to a pretty high level. of course, this is Mini DV on a DV timeline and is only 4:1:1 so I understand why we are getting so much noise.

1. My main question is, will transcoding this and trying to do it in Pro Res give us significantly less noise? I can't figure out if the excess noise comes from the acquisition format, DV, or because the working space is also DV?

2. Even though we are mainly keying on luminance, will the chroma smoothing filter help?

3. Have any other clever tricks that will make the black jacket more visible under bad projection with too much ambient light without affecting the look of the talent's face and shirt and tie, just the black jacket, that will not cause more noise and dancing grain in the jacket?

I am not experienced at compositing and I tried most of the different composite modes and "add" seemed to do the best job as far as making the jacket more visible. If I could just get rid of the noise. This person, of course, appears on camera for the entire video other than b-roll so it all needs to have the jacket raised, it's about a four minute piece.


Re: Need a clever solution to this problem
March 07, 2009 07:24PM
I think you're trying to be too clever by half. If the client is concerned about the black levels, just bring them up overall. You'll lose some of the natural contrast in the shot, since you're reducing the dynamic range, but if what the client wants is a picture where "black" is really a medium-dark gray, that'll do it.

Of course, this will look like ass on your client monitor. But it's supposed to. The only way to really see what you'll get in that room under those lighting conditions is to do a test, and if you don't have that option, you're just gonna have to wing it and hope for the best.

Trying to bring up the black level selectively like you described will, indeed, reveal the buttload of grain that's hiding down in the shadows of your DV footage, because you'll be increasing the contrast in the low end of the luminance curve.

Re: Need a clever solution to this problem
March 07, 2009 08:08PM
Yeah and besides if it's a crappy low end project people won't be expecting THX-quality imagery either. smiling smiley


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Re: Need a clever solution to this problem
March 07, 2009 10:02PM
Also, would getting a better quality projector be in the budget? It just seems that you're going to put a lot of time and effort in making the video's black look "crappy" just to overcome the bad projector.....just thinking out loud.
Re: Need a clever solution to this problem
March 08, 2009 10:34AM
You could bring it to Color, add a vignette on the jacket to lighten up the subject's clothes, play around with the lower regions of the gamma curve to increase the separation of the subject from the black background.

Keying will mess things up, IMHO, as you need a unique color to pull it off, and black on a luma keyer is one of the last things you want to touch.

>Of course when I just up the levels and gamma

You can also use the 3 way CC, as you have more controls over the lower regions than the gamma/levels will allow.
Re: Need a clever solution to this problem
March 08, 2009 03:07PM
Hi all:

Thanks for the words of wisdom. A few more factors...

1. Did some more tests, tried moving the clips to a 10 bit uncompressed timeline (this client is on an old G5 and 5.1.4 so no Pro Res). It did make the clips look slightly less noisy and grainy and overall, it looked better. Of course, coming off of a FW800 drive, I can't play this timeline but since this is for web and DVD, I just export an H/274 QT to check it.

2. Overall quality was still unacceptable for client. I tried applying the Color Smoothing 4:1:1 filter, and once again, it helped a tiny bit but overall, not much.

3. The project itself is not really a crappy low end project, but the way that they will show it will be. Changing out the projectors is not an option since this is for a company that has these projectors in all of their offices where this will be seen all over the world. It's not going to just be shown on a single projector in a single location, each location all around the world has this same crappy projector and the rooms that they show them in are rarely dark, they are sort of darkish but since people have to play with their Blackberries, iPhones and computers, they won't make the room truly dark as they should. Many of the rooms have windows with no blinds or a lot of ambient light.

4. Since this project lives on a slow G5, using Color isn't going to happen.

I think I will just take Jeff's suggestion and try to raise the overall black/gamma levels and leave it at that. Problem is, we don't have one of these crappy projectors here to try this out on so I think I will just bring the client several variations and will see what looks/works best.

Thanks for the advice,

Re: Need a clever solution to this problem
March 08, 2009 03:36PM
Just for the record, I was not suggesting that you change the gamma at all. Gamma, in color-grading jargon, refers to the midtones of the shot. I was suggesting that you make a lift adjustment instead.

But in retrospect, that might not actually be what you need at all. A lift adjustment does just what it sounds like: it raises the entire luminance curve straight up. This has the effect of increasing the luminance values of any of the black parts of the shot up toward gray, but it will also clip badly if you have any highlights in the shot.

I think what you probably want to do is to combine a lift adjustment with a gain adjustment. The gain adjustment changes the slope of the luminance curve while leaving the black point fixed. So you could lift up, then gain down to bring the highlights back to where they were originally.

I wouldn't change the gamma at all, though. If you change the gamma, you're changing the shape of the luminance curve, and that will inevitably make parts of your shot more contrasty while flattening other parts. I don't think that's what you want to do here.

Now, if I remember correctly, the DVX is one of those cameras that records superwhite and superblack, luminance values that are both above and below the normal range for video. So if you do a combined lift-gain adjustment, you might actually have the side-effect of bringing back some detail that was lost in the shadows by black-point clipping, helping make the darker parts of your shot more distinct in the setting where it's going to be screened.

Unfortunately, I don't know how to translate any of that into Final-Cut-color-corrector-filter terminology. One of the common complaints about the three-way CC in Final Cut is that it doesn't use the lift-gain-gamma model used in most color correctors. That's why Color exists, as well as third-party tools like Colorista.

Colorista, incidentally, is wicked cheap, at $200 per seat. I've never actually used it myself, but I'm about to. Trying it out is coincidentally on my to-do list for this week. It's not a real-time tool, but quality real-time HD color correctors are pretty rare, unless you're in the Resolve-Lustre range.

Re: Need a clever solution to this problem
March 08, 2009 03:38PM
> I just export an H/274 QT to check it.

Wow, new hot codec from Apple! tongue sticking out smiley
Uncompressed 10-bit SD is supposed to be able to play off FireWire 800, though...two streams, if I remember right.

I wonder why your clients shot DV if they were so concerned about quality? Or made the guy wear black on black? I had a red suit with a pattern on a red-brick fireplace one time as well. Pretty much the ballgame.
Re: Need a clever solution to this problem
March 08, 2009 06:15PM
If the noise originates from the post-production process then you have a good chance to get rid of the noise with my NoiseReduction plugin (Repair-collection plugins).

If the noise problem comes from the low-end projector, then of course my post-production/pre-projection NoiseReduction plugin can't help.

Re: Need a clever solution to this problem
March 08, 2009 06:58PM
Without looking at the footage, you could take a look at Facelight, which you can get off here.

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