Question on Chroma Key for multiple shades

TravisJ

Member Joined: Apr 12, 2019 21:02 Messages: 57 Offline

Solved by

Oct 29, 2021 19:57

Hi,

I'm definitely not an expert, but need help with Chroma Key, in getting rid of a purple background for a video I am trying to finish right now. Please view this image so you can see what I'm talking about:

https://www.ktravisj.com/bg.jpg

Recently, on another project, I've done a great video where I was in front of a green screen. I did the Chroma Key, and it found all the green, and got rid of it, and published that video and it was awesome.

However, for this video I am trying to finish now, look at that image to which I linked above. Notice how that purple sheet I used as a background has multiple "shades" of purple, I guess you could say..? Anyway, I'm trying to apply a Chroma Key such that it will COMPLETELY get rid of the Purple (in all shades), such that another .JPG room background can shine through as my background.

But it seems like whether

1) I put ONE Chroma Key and set it to the purple and try the two "Color Range" and "Denoise" sliders, or

2) if I try setting multiple Chroma Keys, whereby I try different "shades" of the purple, and then also try the two "Color Range" and "Denoise" sliders,

it doesn't really come out right because the final video sort of starts making the colors within my eyeballs weird, sometimes it may find some of my skin and put a "Hole", etc. etc. It's just not 100% right, and I'm guessing you probably know what I mean. I need

1) all purple gone,
2) all of my skin/shirt/ and my head all intact 100%,
3) and my new .JPG room background shining through as my background.

I'm aware I'm just a beginner at Chroma Key and stuff, but I wanted to ask about any strategies I can use to completely get rid of this purple, and end up getting all of the purple sheet completely gone, such that my other .JPG file that I have set on Track 1 can come throughand be my new permanent background in my final video.

optodata

Senior Contributor Location: California, USA Joined: Sep 16, 2011 16:04 Messages: 8630 Offline

Oct 29, 2021 20:32

Thanks very much for the screenshot and the detailed description.

Short answer, there's no way to get rid of that background by chroma keying. It has way too many color gradients, shadows and wrinkles. For next time, spend the money and get a proper green screen that is a single sheet of perfectly smooth, solid color. Make sure you light it correctly to avoid all shadows as well. The more time and effort you put into prepping you shot, the easier your editing in post is going to be.

Since you've got the work with the existing situation, your best bet is to use a custom mask around the person's head.

You may want to use a brush mask and set the feathering to make the best transition from the clear parts to masked-off area. You'll also need 1 or 2 chroma keys to remove as much of the remaining background as possible near the person's head.

This will be pretty straightforward if the person doesn't make a lot of movement, otherwise you'll need to use keyframing to try and tweak the mask postion (and maybe even shape) in the right place as the clip progresses.

There are many tutorial videos on YouTube, here on the forum and in the Cyberlink Learning Center that will help you learn to use masks and keyframes effectively. You can also click on the Watch Tutorial pop-up when you open the Mask Designer or click on the "?" near the top right of PD's main window and search the online help page for more info.

This message was edited 1 time. Last update was at Oct 29. 2021 20:34

TravisJ

Member Joined: Apr 12, 2019 21:02 Messages: 57 Offline

Oct 29, 2021 20:36

Quote Thanks very much for the screenshot and the detailed description.

Short answer, there's no way to get rid of that background by chroma keying. It has way too many color gradients, shadows and wrinkles. For next time, spend the money and get a proper green screen that is a single sheet of perfectly smooth, solid color. Make sure you light it correctly to avoid all shadows as well. The more time and effort you put into prepping you shot, the easier your editing in post is going to be.

Since you've got the work with the existing situation, your best bet is to use a custom mask around the person's head.

You may want to use a brush mask and set the feathering to make the best transition from the clear parts to masked-off area. You'll also need 1 or 2 chroma keys to remove as much of the remaining background as possible near the person's head.

This will be pretty straightforward if the person doesn't make a lot of movement, otherwise you'll need to use keyframing to try and tweak the mask postion (and maybe even shape) in the right place as the clip progresses.

There are many tutorial videos on YouTube, here on the forum and in the Cyberlink Learning Center that will help you learn to use masks and keyframes effectively. You can also click on the Watch Tutorial pop-up when you open the Mask Designer or click on the "?" near the top right of PD's main window and search the online help page for more info.

Optodata - thanks for the suggestions, I'll give those a whirl. Let me ask--I know this following question is definitely apples-and-oranges because I'm comparing with still-images in photoshop; but is there anyway to, like, do some sort of a "Selection", whereby I can select the person in the video, then sort of use a "Select Inverse", and then that way, the Chroma Key applies to only stuff in the selection (leaving the person in the video untouched by Chroma key) ?

This message was edited 1 time. Last update was at Oct 29. 2021 20:37

TravisJ

Member Joined: Apr 12, 2019 21:02 Messages: 57 Offline

Oct 29, 2021 20:40

Quote

Optodata - thanks for the suggestions, I'll give those a whirl. Let me ask--I know this following question is definitely apples-and-oranges because I'm comparing with still-images in photoshop; but is there anyway to, like, do some sort of a "Selection", whereby I can select the person in the video, then sort of use a "Select Inverse", and then that way, the Chroma Key applies to only stuff in the selection (leaving the person in the video untouched by Chroma key) ?

And I *will* say, the person does not have a ton of movement, throughout this 3-ish/4-ish minute video.

optodata

Senior Contributor Location: California, USA Joined: Sep 16, 2011 16:04 Messages: 8630 Offline

Oct 29, 2021 20:55

Quote ...but is there anyway to, like, do some sort of a "Selection", whereby I can select the person in the video, then sort of use a "Select Inverse", and then that way, the Chroma Key applies to only stuff in the selection (leaving the person in the video untouched by Chroma key) ?

That's basically what masking does. It completely removes everything outside the masked area and you can replace that with whatever your intended background will be.

Chroma keying the small remaining area near the person's head will let you blend in the new background all the way up to their hair, and that's where the keyframing of the mask comes into play as you'll probably need to tweak its poistion, the feathering and maybe its shape to keep things looking smooth.

TravisJ

Member Joined: Apr 12, 2019 21:02 Messages: 57 Offline

Oct 29, 2021 21:07

Quote

That's basically what masking does. It completely removes everything outside the masked area and you can replace that with whatever your intended background will be.

Chroma keying the small remaining area near the person's head will let you blend in the new background all the way up to their hair, and that's where the keyframing of the mask comes into play as you'll probably need to tweak its poistion, the feathering and maybe its shape to keep things looking smooth.

Ok. Totally point-taken, in that I'll buy a better bg next time/or come up with a better one. Cool. Totally right, understood.

As far as this time: I am finding that this "Triangle" mask eats up a BIG chunk of nearly *ALL* the purple. So right now, I'm trying to find a certain combination of three Chroma Key shades of purple, in this video, that will not mess up this subject's skin/teeth/eyeballs, as I go through--*AFTER* taking out this big bite as Step 1 with the Triangle Mask. I feel like I'm like 90% "there" with this approach *this time*, if that makes sense..? So let me ask this:

So do you recommend that with these three "bites" I'm trying to take with 3 Chroma keys (I'm using PowerDirector 17 64-Bit), should I pick those shades closest to the head of the person, in taking these last three "Bites", with these 3 Chroma Keys? Would that be the best? Again--I realize the "best" thing is the better bg, but I am committed on this one, honestly, I'm not going to re-shoot this. And I can actually live with a little purple as a bg coming through, honestly--I don't mind if it has a home-brewn twist/feel at least a little bit. That's acceptable, for this particular video. What I DON'T want is too many stupid-flashing 4x4s or 16x16s (as I intend to produce this 4k) .

This message was edited 5 times. Last update was at Oct 29. 2021 23:13

optodata

Senior Contributor Location: California, USA Joined: Sep 16, 2011 16:04 Messages: 8630 Offline

Oct 29, 2021 21:30

It sounds like you're doing all the right things. I can't give you exact steps but by experimenting and trying out the tools you're building valuable experience and knowledge.

There's always a trade-off between how you want the finished video to look versus the amount of (additional) editing needed to wring out those last nagging details, and by playing with the triangle masks and 3 chroma keys I think you'll end up with something usable without a ton of editing.

TravisJ

Member Joined: Apr 12, 2019 21:02 Messages: 57 Offline

Oct 29, 2021 21:45

Quote It sounds like you're doing all the right things. I can't give you exact steps but by experimenting and trying out the tools you're building valuable experience and knowledge.

There's always a trade-off between how you want the finished video to look versus the amount of (additional) editing needed to wring out those last nagging details, and by playing with the triangle masks and 3 chroma keys I think you'll end up with something usable without a ton of editing.

Word up―you rock, @optodata, and I am grateful for the insights. I'll keep plugging away..

TravisJ

Member Joined: Apr 12, 2019 21:02 Messages: 57 Offline

Oct 29, 2021 23:07

Quote

Word up―you rock, @optodata, and I am grateful for the insights. I'll keep plugging away..

@optodate - this guy on this thread:

https://forum.cyberlink.com/forum/posts/list/0/86063.page#356277

Says I should try "Color Director". But, like what I said in this thread, apparently I'm having trouble even launching this thing. Here's what's happening:

I downloaded it onto my computer, installed it onto my computer. Now, when I run the program, I get a dialogue box that's asking

"Sign in to continue"

And two fields, for

E-Mail
Password

And well, I am TRYING this same e-mail address and password with which I use to log into these forums, which is the same e-mail address and password I used to originally purchase my CyberLink Power Director 17 64-Bit, and, like I say, what I use to log into these forums; but this black dialog box doesn't move. It just sits there and puts a little red-border around the "Email" field, (where it wants me to input my e-mail address) , and doesn't give any indication of moving forward..? What's the deal..? I have no idea how to launch this program obviously. What's the problem? Do you need a screenshot?

Any ideas..?

This message was edited 1 time. Last update was at Oct 29. 2021 23:12

TravisJ

Member Joined: Apr 12, 2019 21:02 Messages: 57 Offline

Oct 29, 2021 23:14

Quote

@optodate - this guy on this thread:

https://forum.cyberlink.com/forum/posts/list/0/86063.page#356277

Says I should try "Color Director". But, like what I said in this thread, apparently I'm having trouble even launching this thing. Here's what's happening:

I downloaded it onto my computer, installed it onto my computer. Now, when I run the program, I get a dialogue box that's asking

"Sign in to continue"

And two fields, for

E-Mail
Password

And well, I am TRYING this same e-mail address and password with which I use to log into these forums, which is the same e-mail address and password I used to originally purchase my CyberLink Power Director 17 64-Bit, and, like I say, what I use to log into these forums; but this black dialog box doesn't move. It just sits there and puts a little red-border around the "Email" field, (where it wants me to input my e-mail address) , and doesn't give any indication of moving forward..? What's the deal..? I have no idea how to launch this program obviously. What's the problem? Do you need a screenshot?

Any ideas..?

Sorry for previous confusion - I am using Power Director 17 64-Bit.