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Is a capture and playback device a passthrough or a pitstop?

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Frank Black
Is a capture and playback device a passthrough or a pitstop?
on Dec 23, 2011 at 4:13:32 am

Hi guys,

Some of you already know that I'm researching the depths of what a capture and playback device does WHAT but that I'm looking for "precise" answers in a language a 2nd grader -- me! -- would understand.

Anyway -- I've been going in circles for 2 and half weeks -- no lie. I have so much in notes -- in word, in notepad, on paper, in emails, IN MY HEAD -- that I need to be UNCOMPRESSED!

I feel like all the answers are in my notes (so many notes). But the dots aren't connecting, and part of the reason is that I'm getting opinions that seem to contradicting but in all probability are most like just not "sensitive" enough. The other part of the reason is that I'm a second grader!

The dots aren't connecting because there actually are "holes" in the lines at the beginning and end the dots are. These holes are cause by the two "parts" mentioned above. I'm stuck MAINLY on one thing! And I need an a "sensitive" answer!! -- not an industry answer! I need (and I say need respectfully) an answer sensitive the level of my mind's current capacity not to shut off the moment an unfamiliar term injects it with fear and doubt.

So here's where I'm stuck (and there's gotta be a simple way to FULLY explain this):

1. why do we say that a cap and play device transfers uncompressed when a camera compresses the data when recording it, and since the camera's decompression doesn't fully restore. a full answer if possible. i will remember your name forever. full meaning something like this (though this probably wrong): well, a camera compresses it, then a cap and play connects to it via sdi, a button is pressed and a camera begins playback, and another button is pressed, and the cap and play sucks the wind out of the sdi and the sdi vacuums the footage out of the camera's playback (yep, takes it right off the LCD), and then it takes the data, encodes it, and shoots it thru a thunderbolt pipe into a mac. oh ye and by the way -- the playback was uncompressed. we call it uncompressed because the playback just orders the lost data to come out where it has fled to and get back in line to form a full original file in all its megabytes, and the guys that aren't coming back -- well we won't even notice they're gone. and so and so. (sorry for getting carried away. thanks if you're still with me. help!)

2. when does the camera decompress -- in playback or when you press the magic "decompress" button.

3. how do aja Io, BM UltraStudio 3d, and MXO2 transfer? does it serve as a passthrough or a pitstop? does it say: hang on data! cant go to the mac yet! we must do something to you first. we must: encode? decode? x? y? z?...

4. do all of the three machines mentioned above capture from playback only?


thanks. i'm in debt to you already if you've read this far.


val


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Andy Mees
Re: Is a capture and playback device a passthrough or a pitstop?
on Dec 23, 2011 at 9:01:17 am

I had a stab at your question here Val
http://forums.creativecow.net/readpost/132/861154


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Michael Slowe
Re: Is a capture and playback device a passthrough or a pitstop?
on Dec 24, 2011 at 6:35:55 pm

Frank, I'm not even a 2nd grader so I understand your confusion. I find it's always best to find one real pro who knows what he's talking about and stop there - don't seek further and further advice and don't get compressed!

Actually I think that once the camera has done its compression no further treatment will restore the lost quality. Most cameras compress on acquisition but with the EX cameras you can take the signal (uncompressed) straight out via the SDI output. So although all the other devices you refer to are treating the signal as uncompressed and are passing it straight through, the original camera compression is retained. I think that's right anyway!

Michael Slowe


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Frank Black
Re: Is a capture and playback device a passthrough or a pitstop?
on Dec 28, 2011 at 1:44:06 am

Andy, thanks again. And Michael, thanks for your effort. Sorry guys both for the delayed response. It's just how things turned out. And Michael, I know what you mean by finding one pro -- but I was confused even by the pros. But I'm good now. A lot of folks pitched in here on the cow and I now, very fortunately, have a very clear picture.


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