Comments

Nick Hope wrote on 10/8/2017, 11:58 PM
When you ask for the waveform or histogram of the still image, do you mean with your color correction applied, or do you mean just normal without any fx?

I meant after you'd applied your FX.

I'll try and simplify it... This is generally what I aim for in clips that contain a range of brightness (highlights and shadows in the same scene, rather than some flat subject). If I render this to H.264 then finally on YouTube (in most scenarios), 16 will end up at 0 (black) and 235 will end up at 255 (white). Note that I have the Studio RGB box checked.

If your addition of brightness lifted the blacks above 16 on the histogram, then it will be above 0 on YouTube and could be responsible for the "missing contrast" you referred to earlier. Ignore the sloping part to the left of 16. That's just noise. It's the "shoulder" that you want to put at 16.

To monitor as it should look on YouTube (in most scenarios), I look at my secondary monitor with the "Adjust levels from studio RGB to computer RGB" box checked:

Or you can install SeMW Extensions and set your preview window to "PC":

Experiment a bit with a few seconds of generated media gray color gradient and upload to YouTube as a private video. Sample the colors with Just Color Picker that I linked to in my last comment. You'll learn a lot quickly.

There's more info in this post, but I approached the subject from the angle of someone discovering that their video has more contrast than expected when it's on YouTube.

MikeLV wrote on 10/9/2017, 11:44 AM

Hi Nick, I downloaded the frame from my original post (as I don't know where exactly it was from in the video), dropped it onto the timeline, set the preview levels to PC on that plugin, checked the studio RGB on the vectorscopes window setting, and applied your color curve only. The first screenshot is with only your color curve applied:

The second screenshot below, is with your color curve, and the brightness and contrast that I applied that appears in the youtube video:

The part that I don't understand is what settings should be checked or unchecked. I think I understand what you're saying about the black and white levels. Assuming all the settings in the software are correct, then you're saying that before encoding to any final format, when looking at the vectorscopes, my blacks should not be at 0, they should be at 16, and whites should be at 235 - is that right?

Nick Hope wrote on 10/10/2017, 12:55 AM

...before encoding to any final format, when looking at the vectorscopes, my blacks should not be at 0, they should be at 16, and whites should be at 235 - is that right?

In general yes, if you don't want to lose details in the shadows and highlights due to clipping. Note that this also makes levels "broadcast safe" and works for DVD/Blu-ray too. So if you get it right for the web, you wouldn't have to do a different adjustment for TV distribution.

The second screenshot below, is with your color curve, and the brightness and contrast that I applied that appears in the youtube video:

By applying extra brightness and contrast in the way that you have, you have pushed the whites up to 255, and anything over 235 is going to get clipped (in most playback scenarios). So on YouTube you've lost some detail in the windows and their reflections in that room at the back. That might not necessarily be a bad thing, as we're looking at the guitarist, not those windows.

Also, in theory, if you put that rendered file out to some TV stations or other producers they might whinge about "illegal" white levels, although these days they'll be used to receiving any old levels and will just deal with it.

If you want to increase the brightness without pushing the white point up, you can do it by lengthening this tangent. Don't take it above the horizontal:

Then you might want to compensate by lengthening the tangent at the bottom left, or pulling it down a little, to increase contrast by darkening the shadows.

This is the advantage of curves; much more control, but at the expense of being fiddly.

This is actually a difficult clip to practice this stuff on, because of the huge jump in luminance between those windows and the rest of the image, and the necessity for that extra anchor which I would never normally use.

Here is a VP13 project. It contains a linear white to black color gradient. On it are 3 disabled Color Curves FX which you can use on general footage. Save them as presets named something like:

  • Map 0-255 to 16-235
  • Map 0-255 to 16-235 increase contrast
  • Clip 16-235


Open your video scopes to see what they do when you enable them one at a time. On footage that has a full 0-255 range of luminance values (like yours), the first one will just map the blacks from 0 to 16 and the whites from 255 to 235 linearly. The second will do that and add contrast.

The third curve just clips off anything below 16 or above 235. I've supplied that one because it makes a great starting point for creating further color curve shapes for footage that doesn't contain a full 0-255 range of luminance. In such a case you would want to adjust black and white points by moving the "inner" anchor points left or right before using the tangents to tweak the shape of the main slope to suit.

I could create more presets for other cameras, since they don't all shoot 0-255, but I've kept it simple for now.

The point with all of these curves is that the end anchors are never moved away from 16 and 235, and you so you won't get values outside that until you render, which will introduce noise outside the 16-235 range, but you can ignore that as it's just noise.

Note that every press of an up or down arrow key moves a point 1 value out of 255, so you could get a point to 16 by moving it to the bottom then pressing the up arrow 16 times. Or you could get a point to 235 by moving it to the top then pressing the down arrow 20 times.

The video scopes are crucial to monitoring this stuff so you can make the right decisions. Once you get used to them, you'll find them indispensable.

One final point. You don't of course have to get your blacks exactly to 0 and your whites exactly to 255 in the finally-delivered video. If you look at Philip Bloom's latest video, his blacks are way up on many clips; about 28 on the shot at 0:28 (actually too high for my personal taste, but it is just a matter of taste):

Nick Hope wrote on 10/10/2017, 1:06 AM

Another thing. In your YouTube video the reds and skin tones have lost a bit of warmth compared to my preview here in Vegas. What format did you render for upload?

Musicvid wrote on 10/10/2017, 4:53 AM

You don't of course have to get your blacks exactly to 0 and your whites exactly to 255 in the finally-delivered video.

High key and Low key scenes always get squished towards one end of the luminance spectrum and lifted off the pegs at the other end. Think of the classic "white cat in a snowstorm" and "black cat in a coal mine" examples given to beginning photography students and it becomes apparent that FILLING the available spectrum is not a requirement or even a goal for creative work.

MikeLV wrote on 10/10/2017, 5:17 PM

Before even diving into your color curves, I think the more appropriate question for me to ask is if there's any instructions or tutorial on using the color curve tool in Vegas because I'm clueless as to how it works. I rendered from Vegas to Handbrake (frameserving script), to H.264 MP4 using the settings in Musicvid's tutorial from several years back.

Nick Hope wrote on 10/10/2017, 9:17 PM

Before even diving into your color curves, I think the more appropriate question for me to ask is if there's any instructions or tutorial on using the color curve tool in Vegas...

I just searched then watched/read a few efforts. I couldn't really find any worthwhile ones. Not a scope in sight on any of them apart from this one from @Dr Zen, but he barely touches on Color Curves; just a bit at the end. There might be something else if you hunt through the tutorials post.

karma17 wrote on 10/10/2017, 10:45 PM

I was reading the Malowz thread and was curious where he says:

"Color Corrector filter is very good for general WB fixes. but i prefer the "invert/correct/invert" trick, as vegas lacks a proper exposure and logarithmic color-corrector filter."

Is this still true of Vegas now?

Is he saying that Vegas is not capable of doing log control corrections like you can in Resolve?

How does the Invert filter change things or make it more precise?

Just curious.

Thanks.


 

Nick Hope wrote on 10/10/2017, 11:56 PM

The explanation was in this comment.

To illustrate, put a generated media "linear white to black" color gradient on the timeline. Apply a Levels FX to it and increase the gamma with the slider. Open the Waveform scope and see what happens. The waveform is "bulgy at the bottom" (technical term 😁); the shadows are getting brightened more than the highlights.

Now put an Invert FX before and after the Levels FX, both enabled, then reduce gamma with the slider. The waveform is now "bulgy at the top"; the highlights are getting brightened more than the shadows.

(I think) @malowz is saying that this is more like how camera exposure behaves, and so is often a superior way to adjust gamma (please correct me if I'm wrong).

Note that this on it's own does not "fix" black and white points.

"Color Corrector filter is very good for general WB fixes. but i prefer the "invert/correct/invert" trick, as vegas lacks a proper exposure and logarithmic color-corrector filter."

Is this still true of Vegas now?

Nothing has changed since he wrote that, at least in terms of the native Vegas effects. The gamma control in the Levels, Color Corrector and Color Corrector (secondary) FX all behave the same. Color correction in Vegas needs some love soon and this would be a good addition.

karma17 wrote on 10/11/2017, 3:56 AM

Very interesting. The only thing I can compare it to is Da Vinci Resolve. When you use the Primary Wheels in Resolve, that is, when you individually adjust the lift, gamma, or gain, you end up affecting, that is, stretching or compressing, the others. However, when you use the Log wheel, which is the logarithmic filter, when you adjust lift or shadows, you only affect the shadows and not mids or highs, so I see there, that log control is much more precise. Perhaps not all that different from what you are doing with the curves by trying to affect one area of the tonal curve without affecting the others. So I guess with the Malowz method, the Invert Filter is letting you affect the highlights more than the shadows with a simple slider control.

I would love to see Vegas 16 or 17 really step up their color correction game too. I almost always just use the Color Curve and it seems to give a reasonable amount of control. But if I really wanted precision, I would probably resort to masking.

As always, thanks for your thoughtful response. Really appreciate it.

MikeLV wrote on 10/20/2017, 11:04 AM

I have to disagree with setting the computer to studio RGB levels prior to rendering. I did that, and uploaded a video to Vimeo, and it was noticeably less contrast-y than it should have been. Unless I'm doing something wrong, (and I probably am), the video looked much better when blacks and whites are at 0 and 255 on the scopes before encoding to MP4.

Musicvid wrote on 10/20/2017, 11:25 AM

Mike, that can be due a graphics, screen, or player with a so-called "Dynamic Contrast" control inadvertently left On. Those controls should never have to be used with correctly streamed video levels. Maybe Vimeo is doing something different these days?

The times one might be tempted to use the switch are with native cell phone and portable footage, which often fills the RGB spectrum.

Here's a much lighter-hesrted look at the whole snafu:

https://www.vegascreativesoftware.info/us/forum/pc-to-tv-levels-a-comedy-of-errors--107325/

 

 

MikeLV wrote on 10/20/2017, 12:07 PM

Thanks, I'll give that one a read. As to the items that you mentioned it can be due to, are there particular settings in Windows, or on my graphics card I should be looking for to turn on/off ?

MikeLV wrote on 10/20/2017, 1:16 PM

So you're telling me this is the correct way to upload to vimeo, youtube, etc? I applied levels and selected Computer RGB to Studio RGB.

malowz wrote on 10/20/2017, 2:11 PM

I was reading the Malowz thread and was curious where he says:

"Color Corrector filter is very good for general WB fixes. but i prefer the "invert/correct/invert" trick, as vegas lacks a proper exposure and logarithmic color-corrector filter."

Is this still true of Vegas now?

Is he saying that Vegas is not capable of doing log control corrections like you can in Resolve?

How does the Invert filter change things or make it more precise?

The invert filter make the logarithmic adjustment to "the other side", a "inverted log".

Trying to adjust brightness in images, i used a camera filming a "gray scale bar chart", i could see easily that the adjustment was not linear, and so "all" the filters to adjust brightness do not worked like a camera does.

Then i tried to find proper ones, and i didn't find a single one. And thankfully i had the "epiphany" of the invert filter to make native Vegas filters a usable way to adjust brightness.

The thing is, even Photoshop didn't do a "proper" brightness adjustment. Then finally the last versions added it. (you can see a "legacy" button in the brightness/contrast adjustment window that button make it works linearly, and contrast too). Now contrast apply a S curve to increase contrast (it's also a logarithmic adjustment).

The fact that now Photoshop do a logarithmic adjustment, makes me think it's the correct way.

It's sad Vegas does not have a proper filter? yes. but as i automated with scripts, it works just fine with no hassle.

80% of my videos i add some brightness adjustments, from tiny to major.

Musicvid wrote on 10/20/2017, 3:17 PM

are there particular settings. . . on my graphics card I should be looking for to turn on/off ?

Yes, make sure "dynamic contrast" or something sounding equally tempting is turned off.

Musicvid wrote on 10/20/2017, 3:50 PM

Ah, I see now, and it appears to be an error on the side of caution.

First, your source is very conservative. You could probably add a little zebra and still be ok.

Second, and I promise you that Nick, I, and others here have done the same, is to include all recorded values in the 16-235 range. I would set the red lines to about those numbers and see how it looks on Vimeo.

So basically no, you do not need to flatten the image with a Studio RGB levels filter prior to rendering. The shooter already did that for you (nice work)! 😅

Musicvid wrote on 10/20/2017, 3:52 PM

And your graphics settings are probably fine.

MikeLV wrote on 10/20/2017, 3:52 PM

nvidia control panel the right place to be looking? Here's some color settings, dont' see anything out of the ordinary here?

Musicvid wrote on 10/20/2017, 3:53 PM

heh beat you by a matter of seconds...

MikeLV wrote on 10/20/2017, 3:56 PM

Musicvid, now I'm really getting confused. The screen capture I posted is WITH the studio levels applied. Without them applied, black is 0 and white is 255 on the scopes. Here is the same screenshot, without any effects at all applied:

Musicvid wrote on 10/20/2017, 3:56 PM

btw, i don't know how a levels filter would work with the inverse gamma trick above.

Musicvid wrote on 10/20/2017, 4:15 PM

Edit: Got the grab. These are from the Vegas preview and not a player, correct?

I predict we will see the knee and shoulder of the curve somewhere near 16, 235 respectively. The rest can be used sparingly as a visual cushion using the sliders.

If everyone shot like you do, this forum would be a happier place.

 

MikeLV wrote on 10/20/2017, 4:24 PM

Both screen grabs are from the Vegas timeline, saved as PNG best quality. The first one had the studio levels applied. The second one I just posted does not have the studio fx applied. So my question remains - should I apply the studio FX or not before frame serving to HB and encoding the video to upload to Vimeo, YT, et al.? RE Shooting, that was just luck that it came out good, not skill, thanks for the compliment! I'm actually not pleased because I could not use the hair light as it caused hum noise with the guitar :-(