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Just to understand the easiest way how to compose a footage with black bacground with an other background

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Richard Heinrich
Just to understand the easiest way how to compose a footage with black bacground with an other background
on Feb 1, 2016 at 11:54:26 am

Hi guys,

great to be here. I'm just asking for sake of understanding. I have a very tedious project and I using Sony Vegas PRO 12, where I first had to prepare the green box files to work with, which really was a "pain in the ass".

The green screen shots were very uneven, lots of shadow, wrinkles, different shades of green. Total shots with other elements in it. So I had to mask it and keyframed it as well. I really got it with different tools from BCC to Sony's own plugins and one footage I had to even cut out in After Effects.

BUT just to understand.

When I have my footage A with already a black or white background and I use any of the composite modes from add, multiply to whatever to put my footage in front of an other footage B, so I will not get a result as I would, when using a green background (solid green media) for the first footage A and then using the chroma key. Is this correct ?


Sorry, it may be a bit confusing and also my English it may be a bit sluggish (German ;-).


I try to say it differently.

1. When preparing my footage the client sent to me, I used for some just a mix of differnt plugins to get rid of the green background. The result was a footage with only the actor and the background in black (I tried to put a white background underneath) . In this case the "black" was transparent. So I could use it directly with another background footage.

2. BUT, when I would render the footage with the black/white background and insert it in a new project and try to put an other background underneath of the first footage, I will not get the same results, cause the "black" will not act as it would be "transparent".
And no composite modes will work to geht the same results like in the 1. example.

Is that correct ? Or I'm missing something ?

Or is there a way that I have not discover yet ?

Thank you very much and have a nice day.

Greetings from Germany

Richard


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Richard Heinrich
Re: Just to understand the easiest way how to compose a footage with black bacground with an other background
on Feb 1, 2016 at 12:29:53 pm

alright,

there is a way I figured out that the "black" will rest transparent. It's only if I save my footage as a project and insert it as Vegas project file into my main editing project. The black will act transparent.

Unfortunately you can't just simply replace a media file with a project file. That would make it just a lot easier, because I have my MAIN PROJECT already edited and need now only to replace the files with the green screen with the new footage.

So the only way is to re-edit it. But I know what I will do to improve my workflow. I will place a bounce of my previous master file so I have a reference where to cut. Actually even better. I will already trim my files in the single projects. Wow what a pain, but also a lot of learning. ;-).


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John Rofrano
Re: Just to understand the easiest way how to compose a footage with black bacground with an other background
on Feb 1, 2016 at 2:13:20 pm

As you have seen, Black is not Transparent. That's because there are 4 channels. RGBA (Red, Green, Blue, Alpha). The RGB values give you the color (in your case Black) but only the Alpha channel will provide transparency.

To solve your problem, you need to render with a codec that supports an Alpha channel! Rendering uncompressed with preserve the Alpha channel but the files are extremely large. QuickTime PNG preserves the Alpha channel as does the QuickTime Animation codec. You will need to create a custom template for this which should look something like this:



It's really important that the Compressed Depth be set to 32 bpp color. That's what preserves the alpha channel.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Richard Heinrich
Re: Just to understand the easiest way how to compose a footage with black bacground with an other background
on Feb 1, 2016 at 7:46:05 pm

Thank you for your reply, John.
Your explanation taught me an important technical aspect about the color space in film I do understand now.

I will try out the template you showed me.

Best Richard


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John Rofrano
Re: Just to understand the easiest way how to compose a footage with black bacground with an other background
on Feb 2, 2016 at 2:47:25 pm

Glad that was helpful. Let us know how you make out.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Richard Heinrich
Re: Just to understand the easiest way how to compose a footage with black bacground with an other background
on Feb 4, 2016 at 1:53:44 pm

Hi John, hi community,

unfortunately the template above didn't work for me. I followed exactly your instructions, John, but the Alpha Channel was not preserved. so I sticked to my first approach to work with several single projects importing into the Main Project.

Keep it short. After having Vegas crashed many times, and after having done some post corrections I finally got the final bounce. But first I had to figure out why Vegas won't render my mp4 file. Like after 67% of rendering it would stop.

So I tweaked the settings. And the only thing which worked and seemed to be relevant to not stop the rendering was: setting the "CUDA" on, what the hell that means ;-).


But hey, where are the days of DV ? It was so simple and pleasant to work and edit.

Is it only me or is editing in HD even if using the PRO Res422 codec to work with a really CPU consuming matter ? I had always to generate a "dynamic RAM preview" to see if an effect is working or not.

But maybe it was also because I worked wit lots of single projects so which may slowed down Sony Vegas.


And I may not have that "supermachine" as a computer it may be outdated today. But it's a

icore7 with 16GB RAM with a RADEON HD6550.

I have also to say, that I'm mainly doing audio productions. So I was not used to edit videos anymore.

Anyway thank you, john. I saw also some of your tutorials on youtube, which helped me on my way to get the final result.


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John Rofrano
Re: Just to understand the easiest way how to compose a footage with black bacground with an other background
on Feb 4, 2016 at 3:40:24 pm

[Richard Heinrich] "unfortunately the template above didn't work for me. I followed exactly your instructions, John, but the Alpha Channel was not preserved. so I sticked to my first approach to work with several single projects importing into the Main Project."
That should have worked so if you want to detail the steps you are using in your workflow, maybe I can see where the alpha channel is being lost.
[Richard Heinrich] "Is it only me or is editing in HD even if using the PRO Res422 codec to work with a really CPU consuming matter ? I had always to generate a "dynamic RAM preview" to see if an effect is working or not. "
It really depends on what HD codec you are using. There are many of them (not like DV) so if you are using HDV or AVCHD you should have a smooth editing experience. Having the right GPU also helps a lot (which you seem to have).
[Richard Heinrich] "But maybe it was also because I worked wit lots of single projects so which may slowed down Sony Vegas."
Lots of nested projects will definitely slow things down depending on what is inside those projects. Rendering them out will definitely help performance.

~jr

http://www.johnrofrano.com
http://www.vasstsoftware.com



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Richard Heinrich
Re: Just to understand the easiest way how to compose a footage with black bacground with an other background
on Feb 4, 2016 at 4:33:05 pm

[John Rofrano] "It really depends on what HD codec you are using. There are many of them (not like DV) so if you are using HDV or AVCHD you should have a smooth editing experience. Having the right GPU also helps a lot (which you seem to have)."

I think you recommended once here in the Forum

the Sony MXF HD 422 1920x1080 at 50Mbit/s is that correct ?

So I used it. Or is there a better codec to work with ?

[John Rofrano] That should have worked so if you want to detail the steps you are using in your workflow, maybe I can see where the alpha channel is being lost.

Gotcha ;-)

after rendering
I have to right click on the clip on the timeline and adjust the properties of the clip to make black disappeara and get my alpha channel.
That was, what I was missing.

YES IT WORKS.

Thank you


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John Rofrano
Re: Just to understand the easiest way how to compose a footage with black bacground with an other background
on Feb 4, 2016 at 4:53:49 pm

[Richard Heinrich] "the Sony MXF HD 422 1920x1080 at 50Mbit/s is that correct ?"
Yea, that should edit quite smoothly on a modern computer with a good GPU. It could be just the nested projects slowing things down.
[Richard Heinrich] "I have to right click on the clip on the timeline and adjust the properties of the clip to make black disappeara and get my alpha channel. That was, what I was missing."
Oh yea, I forgot that Vegas Pro doesn't always see the alpha channel unless you tell it it's there. Glad you found that.

~jr

http://www.johnrofrano.com
http://www.vasstsoftware.com



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Richard Heinrich
Re: Just to understand the easiest way how to compose a footage with black bacground with an other background
on Feb 4, 2016 at 5:10:52 pm

I've just realized just by playing around with the original clips with the green screen already converted in my working codec, I will get better results, when I first do all my changing to the actors skin like colors, contrasts. Then render it out and afterwards to get rid of the green by multiple keyframing. It preserves a better quality of skin and contrast colour.

I did it the other way when starting and I finished by messing up all my skin colours where it was more difficult to get them back at "normal" level without increasing the "green" background.

Wow. It was a great lesson. I really thought, that the green screen clips will be easy to handle.
Next time I will shortly check it, if it's easy or will be time consuming before accepting the job.

Anyway the quality of the shots and the clips provided by the client and made by a so called movie company were very crappy. I did the best I could out from it.

Thanks for your help, John.


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