Chroma Keyer makes movie sluggish?

lou4uandme wrote on 4/3/2001, 8:20 AM

Hi everyone,

I just started using Vegas 3 days ago, so forgive me if
this question has been addressed.

I created a "moving sphere" in 3D studio max and saved it
as an AVI. I then took a movie scene and used "Chroma
Keyer" to extract the blue screen. It worked fine except
that the movie is "sluggish" or lost a few frames/sec.

Is this normal?

My system is..
P4 1.4 Gig
128 ram
directx 8
hard drive maxtor 7200 RPMs "new & defragged"

Thanks,
Lou

Comments

SonyEPM wrote on 4/3/2001, 9:10 AM

Rendering an uncompressed .avi in Max, with an alpha
channel, would be a much cleaner solution- no chromakeying
needed.

lou4uandme wrote on 4/3/2001, 10:00 PM

Hi again,

Ok, that sounds like a great Idea.
Does anyone know why using chroma keyer would cause the
movie to become sluggish? I'm worried that I will have it
happen again when I use 2 videos instead of 3D Studio max.

Thanks,
Lou

jrsunshine wrote on 4/4/2001, 8:08 AM

Are you saying a Non-Sonic Foundry solution is the better
solution for Chroma-keying? Is this true for all types of
keying (ie: Blue/Green screen)?

Roy Hinkle

SonyEPM wrote on 4/4/2001, 8:55 AM

Chromakeying is very processor intensive, so it may well
slow down your PREVIEW frame rate. Once you render all will
be well.

Also, Chromakeying (anybody's, including ours) has quite a
few controls that allow you to tweak the key. This is good
for bluescreen keys(weatherman), but leaves room for
operator error. If you have an alpha channel embedded in an
uncompressed avi, there's less room for user error, and
you'll probably get a cleaner key.

FadeToBlack wrote on 4/4/2001, 5:07 PM

SonyEPM wrote on 4/4/2001, 5:09 PM

You can't save alpha w/ avi in all apps. Chromakey is an
option in that case.

FadeToBlack wrote on 4/4/2001, 11:41 PM

SonyEPM wrote on 4/5/2001, 9:17 AM

How it gets embedded in an avi in the first place varies
with every program. Check the docs.

Once you bring that file into Vegas, you can turn on the
alpha in media properties.

FadeToBlack wrote on 4/5/2001, 4:23 PM

SonyEPM wrote on 4/5/2001, 5:25 PM

3D Studio Max, Adobe AfterFX & Photoshop, and Vegas Video
all allow you to save an alpha channel with an uncompressed
avi.

SonyEPM wrote on 4/5/2001, 5:32 PM

Also, from Cool3D you can save as a tga sequence w/alpha,
and open that in Vegas.

1)Set default still length to 1 frame
2)Set tga alpha interpretation to premultiplied in media
properties (and save profile)
3)sort tga sequence by date (earliest first)
4)select all, drag to the Vegas timeline.

This will work-

SonyEPM wrote on 4/5/2001, 5:46 PM

slight correction: Photoshop lets you save stills with
alpha.

Cool3D will let you save a tga sequence with alpha channel-
you could bring those stills into Vegas as a sequence. Not
a perfect solution, but you could get it to work.