Capturing to computer?

M

MachinePhilby

Member
Hi people,

I'm interested to know about using a composite feed to the computer to capture the images. I want to know if there is any benefit in capturing this way to a better codec such as DVCPRO - or something better than DV.

For instance, would I get a better result with greenscreening if I can capture a not-so-compressed image?

Cheers, Phil
 
The DVX has composite, s-video and firewire for output. Your captured video from the DVX is in the DV format. Outputting to composite or s-video has lower resolution than DV plus your converting, which introduces losses. Therefore, firewire has zero loss from your DV source.

To get better than DV output the DVX needs to first capture better than DV25, which is not possible.

...Angelo
 
Neither the composite nor S-Video (Y-C) outputs are progressive as these interfaces do not support progressive. Even if the camera offered a color difference output (component or Y-Pb-Pr) analog output, it would still be inferior as capturing form any analog source would insert two additional mode conversions in the signal path (camera's digital format to an analog output to an analog capture card to a digital storage device).
 
What about if it's coming from a better camera than your average DV cam?

We have an odd setup... I have access to a studio quality cam but everything is recorded onto DV tape. If that cam outputs a better image would that be worth the hassle?

It's some Sony studio cam that you can change the backing. As far as I'm aware we only have a VTR backing for it which outputs a signal to a deck. It has a 2/3" chip... Would this make any difference?
 
...also, the decks can run firewire to comp...

Or doesn't it matter how good the cam is... if your still going through analog feeds then your image wouldn't be as good as DV?

I'm probably trying to fool myself into something that isn't possible :)

I'm a student and just keen to learn and get the best out of what's available to me. This is probably chickenfeed talk for most people here!! I feel kind of stupid!!!

But yeah... basically it's coming out of a cam with VTR backing that feeds into a deck that can run through firewire to comp... still won't be as good?
 
MachinePhilby said:
Or doesn't it matter how good the cam is... if your still going through analog feeds then your image wouldn't be as good as DV?
Click to expand...

It matters in that the quality of the camera's optics and CCDs as well as the digital to analog conversion would effect the quality, but no matter how good it is, this configuration still is inferior. Going the DV to DV route avoids two different set of conversions and will give you the best results. Since this is an option based upon what you have stated, then I would strongly recommend that you go this route.

Specifically, what were you hoping to accomplish by using an analog interface?
 
The analog setup is just how the cam has to operate. I wonder if I am better off using a VX2000 instead of the studio cam!!!???

We don't have a choice but to run the studio cam through this analog way. Our big cam has a VTR backing only, which runs to it's power supply that has BNC cabling out only!

I'm beginning to think I'm better off not using that cam even though the bluescreening is the only reason we have it setup!!! Perhaps I'm more likely to get a better key using the VX2000!!!???
 
Just so we are clear about the setup:
(the cam is one of those Sony ones where you can change the backing on them. We ONLY have a VTR backing)

Cam that has a VTR backing with feed to power supply unit.
Power supply unit has only BNC connection that runs out to deck.
Obvisouly we can capture at the deck, but we can also run through firewire feed to comp.

My query was would I get a better image by captruing through firewire to comp in a less compressed image (like DVCPro50 or somehting along those lines) using the firewire feed... It's been made clear to me that since this setup uses an analog signal at some stage (from the power supply unit to the deck) it won't make any difference since the image is being 'ruined' by the analog line :)

So now I guess my question would be should I use another camera altogether that doesn't use an analog feed? I mean capture straight to DV tape itself on a VX2000 (or whatever is available at the time) Even though the bigger camera has far better image capture (onto the ccd's) because that is run through the analog line then my great image becomes extremely compressed... would I be better off capturing to another camera altogether that doesn't use this analog feed?

Would I actually be getting a better image for bluescreening purposes using a camera that simply captures to DV tape without any inbetween-compressed lines etc.?
 
What moddle camera and back are you using?
What format is the 'deck' output on the camera/what format outputs are on the camera?

For chroma-key work, you'd actually be best to avoid DV compression, and full use the analog feed raw into your copmuter, using a dedicated analog capture card. Preferably if you have Component outputs on the camera.

Best of course would be if you could get SDI out of the camera and go into an SDI capture card.

- Mikko
 
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