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Old January 23rd, 2011, 06:13 PM   #1
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? about Vegas and green screen

Sometimes when I shoot green screen the client uses the footage for thier website. I'm talking about he type of video where when you go to the site and a person walks on screen and gives a message. Typically I just turn over the tape and the web guys do the rest. Now the time has come where a client has asked that I edit the footage with the alpha channel either turned on or off so the footage can be placed directly on the site. Is this somehting that Vegas can do? If so, how should the video be exported? I was going to purchase Vegas but I need to make sure that this can be done. Also, whats Vegas capeabilities when it comes to making adjustments that help pull clean keys?
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Old January 23rd, 2011, 07:02 PM   #2
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no problem - other than deciding which codec to use - you need one that has alpha channel. eg. uncompressed avi. qt....
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Old January 23rd, 2011, 09:19 PM   #3
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So is there a feature or box that needs to be checked in order to export with the alpha channel? Its more to it than simply keying out the green and exporting as an uncompressed avi correct?
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Old January 24th, 2011, 08:50 AM   #4
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Kevin, on the uncompressed AVI renderer custom screen, there *IS* a checkbox that must be checked to include the alpha channel.
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Old January 24th, 2011, 09:52 AM   #5
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What Edward describes is the typical render out of Vegas for this kind of work. But that's just a step along the way.

To my knowledge, there is only one distribution codec in use for this work, and that's VP6 in a Flash/flv container. Vegas doesn't have access to this, you'd need to take your uncompressed AVI with transparency out to another encoder. The encoders that support VP6 with transparency cost money. There is a Wildform encoder with VP6 that's not too spendy, but I'm not sure if it supports transparency.

The typical method is to use Adobe's Flash application, which includes Adobe Media Encoder. After creating an flv/VP6 file, it's on to Flash to create a transparent player without controls, with the flv embedded in a swf.

This is the only method I'm aware of - it's an advanced project and is quite complicated. Maybe there's an easier way out there, but Flash is the king of layering and transparency on the web, and this is the way to get there.

OTOH, if your client will accept an uncompressed AVI with transparency, Vegas can do that!
30 years of pro media production. Vegas user since 1.0. Webcaster since 1997. Freelancer since 2000. College instructor since 2001.
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Old January 24th, 2011, 11:20 AM   #6
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So it sounds like Vegas can do its part, but after that its up to whoever does the programing for the website to do the rest. Does this sound right?
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Old January 24th, 2011, 03:06 PM   #7
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I shoot a lot of greenscreen, and here's what I (and others on other forums) have concluded:

1. You can render out as a .PNG series with alpha. Or, you can render to .MOV and choose the animation option (I don't use this, so can't give details). Either one will give a transparent alpha, and either one should be compatible with MACs or Linux boxes (both of which are much more popular in the Hollywood area among the pros, where my daughter works in a post-production house as a producer).

2. However: You CAN NOT render out a clean alpha from Vegas. The problem is that it always will have a dark halo around the image. The halo is not so great that you may not be able to live with it, especially if you are shooting HD and then you or someone wants to downrez to SD.

Experiment and see for your self on a very short loop area on your TL, then put the resulting .PNG series back onto the TL. First, create the greenscreen chromakey preferrable with NewBlue Essentials II, or an even better keyer. If done with care from a file created with a properly lit greenscreen, you will not see a dark halo to any significant degree in the Preview window before you render. Then put the .PNG series on a new track that is on top of all the others.

You'll need to go to Properties>media and click the appropriate alpha box in order to see the alpha as transparent. And, in order to see the halo, you'll need to put a light-colored generated media track under the other tracks on the TL. Be sure to mute the original track(s) so that only the new rendered image sequence and the generated media track are visible in the preview window. Then inspect it and see if it looks OK - by your standards. If so, render to SD - if that is your final destination - and look again. If it doesn't look good on your TL, it's not going to look good on theirs either.

I do render out clean alpha channels from Particle Illusion and other software using Logarith (usually), but I never try to create alphas in Vegas - only complete composites with chromakey as needed over the final intended clips or stills.

I'm not sure this problem is limited to Vegas. I've also had similar problems with CineGobs. But you might try it to see if you get better results. Render out a good intermediate, such as Cineform, import into CineGobs, create a render with alpha - probably with Logarith - then bring it back into Vegas and make a judgement. CineGobs is not that bad - for free software.

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