Chromakeying with Firewire

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DorisEdwards

New member
Hello,
We are doing a lot of chromakeying in post production, using a lightring and chromatte. But we are not yet quite happy with the chromakeying results.

The manufacturer of the chromatte/lightring strongly recommends to capture footage not with Firewire (Firewire compresses video and, therefore, important colour data is lost. For example, video is sampled at 4:2:0 in PAL)

So, they recommend as BEST output as Component/SDI, and second best via Y/C (s-video)

We are using a DVX100BE, Final Cut Pro Studio (latest version) and a MacPro, top of the line. The DVX100BE does not have SDI output but it does have an s-video output.

Here are my questions (and confusion)
1) Is there an alternative to capturing via Firewire into Final Cut Pro, circumventing the compression issues caused by Firewire?

2) The footage is already compressed when recorded to the camera's mini tape. So, how can I capture the "purest", i.e. the most uncompressed footage for editing in FCP? I guess this means "exporting" from the camera directly into FCP via some hardware? (and not using the tape?)

3) I have read many threads about firewire issues in this forum and retained a recommended link by Barry Green: http://www.grassvalley.com/

But I am a bit lost about understanding the whole workflow.
Thanks for helping me. Kind regards, Doris
 
yes, you got it. Basically the concept is to use the camera head to get the signal and record another way. Some people use PCs , since it is the cheapest way , but others use expensive recorders mainly for portability.
If you run green screen, chances are you can easily get a pc installed somewhere to capture directly from the camera.
A good card (cheap) is the blackmagic intensity (pro or not) because it can record HDMI and Components, as well as Composite and Y/C , but if you can, components is definitely the way to go.
unfortunately your camera has only YC has best choice.

You can also find display adapters with YC/composite input.
Some others USB devices exists but they are usually on the cheap side of technology, so no great result to expect.
Another way is to shoot HDV or XDCAM-EX since the extra resolution given allows to get closer from what an SD 4:2:2 would be.
 
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Chromakeying with Firewire (Continued)

Chromakeying with Firewire (Continued)

Thanks very much for your answer.

I might well purchase the Blackmagic Intensity card, even if I only get YC and not Component.

I am not ready to replace the DVX100B just as yet. But I do have one worry:

We are filming in squeeze mode 16:9 which transfers well into FCP via tape. I wonder whether this squeeze mode is retained when transferring directly via YC?

What do you think? Kind regards, Doris
 
FCP is pretty versatile. I don't imagine you would have much trouble with squeeze mode however you're transferring it.
 
If you are shooting green screen stuff, does the content allow you to shoot full 4x3 to get the DVX's maximum resolution (and best bet for pulling a good key) and composite that into a wide screen time line?

I would think this would allow for the highest quality source material.
 
Ya squeeze takes out 25% resolution, so there may be fringing around part of the subject. I would recommend shooting 4:3 and then cropping after you key.
 
the SDI would be an uncompressed (either 4:2:2 or 4:4:4) output. The DVX doesn't have that option. Anyway you get the footage: tape, firewire, composite, whatever, is going to be after DV compression, unless of course, you have the andromeda mod.

Light properly, and look into Red Giant Software's Key Corrector to make it look a little better.
 
for the squeezed mode, you have to check.
most cameras allows both modes, usually selected in a menu as "TV type".
if you select 4:3, then signal comes with black bars (letterboxed) and if you select "wide or 16:9" it comes squeezed (and unsqueezed by the TV set).
so select the mode that output a squeezed picture to get full resolution.
 
nosys70 said:
for the squeezed mode, you have to check.
most cameras allows both modes, usually selected in a menu as "TV type".
if you select 4:3, then signal comes with black bars (letterboxed) and if you select "wide or 16:9" it comes squeezed (and unsqueezed by the TV set).
so select the mode that output a squeezed picture to get full resolution.
Click to expand...

Those are not the menu options for the DVX, though. For the DVX, it's under Aspect Ratio and it's called Squeeze.
 
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