chroma key export

[Rafael Amador]

[Eric Grush] ” My problem is that whenever I render I get a black background”
[Eric Grush] “When I use a temp background it comps great. Without a background I get fuzzy edges and some bleed”

So what are you getting, a black background? Or a bad transparency?
If you are getting a black-solid background, you maybe exporting without Alpha channel.
Which codec are you using? Animation Millions+?
You say you “Without a background I get fuzzy edges and some bleed”. When, before exporting? Or when you reimport the clip?

Mac OX 10.5.2-FC 6.02-QT 7.4.1
G5 2x2Gh 4GbRAM-BlackMagic Extreme
PMBP 17″Core2Duo 4GbRAM-AJA ioHD
JVC DTV-17″
SONY EX-1 . SONY PD170
..and always a big mess on top of the table.

[Eric Grush]

Ah…the fuzzy edges are before export, without a background. When I try with a background the composite looks clean. As for export, the client wants a full size (1920×1080) H.264 so they can use it in various backgrounds in flash. Somehow my alpha settings aren’t translating when I export this way. Is is best to use straight, black, white? Suggestions.

Thanks

ERic GRush

[Tom Matthies]

I’m not sure if H-264 supports an alpha channel. At any rate, export your clips WITHOUT rendering them to preserve the alpha channel. Try Animation at millions+ just for an experiment and see how that works.
Tom

[Zak Mussig]

The trick to exporting from FCP with alpha is to keep your keyed footage on track 2 or above and don’t render before exporting. Rendering makes the background black pixels as opposed to transparent pixels displayed as black. Also, export using the QuickTime conversion option as Animation w/ millions of colors+.

This works well for me since my good keyer is an FCP plugin, but I usually composite in Motion. I don’t have AE [:( ] or I would probably use that.

Hope that helps,
Zak

[David Bogie]

Your client is a clueless doof. H.264 does NOT support alpha. They cannot edit H.264 anyway, it’s a delivery format.

You will provide them with .mov using the Animation codec at sequence settings.

bogiesan

This is my standard sigfile so do not take it personally: “For crying out loud, read the freakin’ manual.”

[Eric Grush]

Thank you all very much. I will explain the delivery issue to the client and export unrendered .mov files with the animation codec using millions of colors to preserve my alpha. I really appreciate all the help.

One more question.

What is the best alpha setting for chroma keyed material? Straight, so that it does not interfere with any black or white material in the image?

Thanks again,

Eric GRush

[Michael Gossen]

Where are you seeing it just has black in the background? If you open a QT with an Alpha in QT Player, you will see a black background. You need to re-import and overlay it on something to see the transparency. And the Animation codec is correct to deliver quicktimes with transparencies.

Michael Gossen
Helium Digital Media

[Rafael Amador]

Erich,
In FC you have NO OPTIONS of exporting different kind of A-channel like in AE or Combustion.
In FC is even Easier. You only needs to export with a codec that support A-channel.
– Make your composition. With a background to see that the A-channel works.
– When you are happy, delete the background.
– Open the Sequence Setting.
– Quick Times Video Setting> Compressor> Choose ANIMATION
– Click the ADVANCED window.
– Instead of Millions, choose MILLIONS +.
– Export.
You will get an Animation movie with an Alpha channel that you can send to your customer to compose with any background.
As David Bogie says you an not export as H264. That codec do not have A-Channel.

Mac OX 10.5.2-FC 6.02-QT 7.4.1
G5 2x2Gh 4GbRAM-BlackMagic Extreme
PMBP 17″Core2Duo 4GbRAM-AJA ioHD
JVC DTV-17″
SONY EX-1 . SONY PD170
..and always a big mess on top of the table.

[Rafael Amador]

[Eric Grush] “What is the best alpha setting for chroma keyed material?”
Eric,
As I wrote before in FC you have not choice. Always export “Strait”.
In AE, SHAKE or COMBUSTION, you can choose which kind of Alpha channel to export with.
You need to choose depending of what you go to do with the keyed footage and which application you use to do the composition.
If you only will compose, pre-multiplied is OK. Is ready to compose.
But If you intend to apply an effect, for example Color Correction, in some applications (AE, SHAKE..) you need to de-multiply before to do so. Otherwise your effect would affect to the Alpha channel too.
More important than the kind you choose is that the applications (FC, AE,.) recoignize the proper kind of Alpha.

Mac OX 10.5.2-FC 6.02-QT 7.4.1
G5 2x2Gh 4GbRAM-BlackMagic Extreme
PMBP 17″Core2Duo 4GbRAM-AJA ioHD
JVC DTV-17″
SONY EX-1 . SONY PD170
..and always a big mess on top of the table.

[Eric Grush]

Thanks everyone for the great information. The tup on the Chroma Smoothing filter really helped as well. I will explain the to client all of the reasons why they were mistaken in their requirements and send them the Animation files as you have all explained.

Your insights have again been hugely helpful and are much appreciated as I learn more every time I read and use the Cow forums.

Thanks again for keeping this community thriving and supportive.

Eric Grush