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shooting straight to hard drive with ag-dvx100


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#1 Andy O'Neil

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Posted 20 July 2004 - 07:06 AM

?November? (2004) was directed by Greg Harrison. The DP was Nancy Schreiber, A.S.C., and the production company was IFC Productions. The film was shot on two AG-DVX100 cameras and a third camera for pick-up shots. Greg Harrison referred to ?November? as ?entirely a digital desktop movie.? He added that, ?Picture and sound never hit tape, staying on a hard drive until [their] final output to HD,? http://www.panasonic.../news04_010.asp.

A Panasonic representative confirmed that both the AG-DVX100 and the advanced AG-DVX100A are capable of shooting directly to a hard drive.

To achieve this, Panasonic says, the camera needs to be connected via FireWire to a computer, a computer that has editing software capable of sorting out the digital footage. Unfortunately, carrying around a portable, external Lacie hard drive during our shoots simply wouldn?t cut it.

According to Panasonic, an external hard drive itself cannot sort out the digital footage. Software (like Final Cut Pro) is needed to effectively compile and sort the ?1s? and ?0s? or bits and bytes of the digital footage. Otherwise, various unnamed problems can occur. A hard drive itself probably wouldn?t work at all, but Panasonic has not actually tested this process.

So, we would need (1) a camera, (2) a laptop or desktop computer with sufficient storage capacity that we would be willing to tote around on shoots, (3) non-linear editing software, and (4) a means of connecting the camera to the computer, i.e. a FireWire cable.

Panasonic also confirmed that bypassing tape altogether by shooting straight to a hard drive would circumvent compression and salvage image quality, however, tape could be used simultaneously for back-up purposes.

I cannot believe that Greg Harrison and his crew carried around a computer for hand-held shots. It doesn't make sense.

Does anyone know more about this or who I could contact to learn more?

Thank you for taking the time,

andy
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#2 Phil Rhodes

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Posted 20 July 2004 - 09:52 AM

Hi,

> A Panasonic representative confirmed that both the AG-DVX100 and the
> advanced AG-DVX100A are capable of shooting directly to a hard drive.

Well duh. Any camera with a firewire output, from the PD-150 to the DSR-570, is capable of doing this. I regularly do it with my portable edit equipment and Panasonic AG-DVC200 camera.

> According to Panasonic, an external hard drive itself cannot sort out the digital
> footage. Software (like Final Cut Pro) is needed to effectively compile and sort
> the ?1s? and ?0s? or bits and bytes of the digital footage. Otherwise, various
> unnamed problems can occur.

Well that's a bunch of half-true, confusing non-information. The word "compile" is particularly misleading. It's true that you can't generally use a standard firewire hard disk drive to record firewire video; the nearest analogy I can think of is that it'd be like two people conversing in the same language on two completely different subjects, resulting in a conversation that made no sense at all. However this is a hard-disk control and interfacing issue, nothing to do with application software like Final Cut. There are no "various...problems," it just won't work.

To be more technically specific, the output of a DV camera is best described as a contextless stream, just one frame after another for as long as the connection is there. A hard disk drive expects "chunks" of data every so often, together with data which is nonsensical to a video camera such as filesystem information, (Mac? Windows? Linux?) which file the data is part of, how much more the drive should expect, etc, etc. They might both be firewire interfaces (and actually they're usually normal ATA hard drives with 1394 convertors on them) but it's a completely different type of data. This is, by the way, intentionally in fairly generic language, I don't want to have to write a four-page essay on filesystem considerations for network attached storage.

In essence, the camera has to care far less about the context of the data it's sending.

> I cannot believe that Greg Harrison and his crew carried around a computer for
> hand-held shots. It doesn't make sense.

No, it doesn't make any sense at all for a dramatic production. If you're in a news situation or some other circumstance where you want to start cutting as soon as possible then it can be useful.

Phil
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#3 Mitch Gross

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Posted 20 July 2004 - 09:54 AM

Don't know what November did, but there are a number of portable hard disk recorders such as the Firestore. It is important to note that they all record the signal via Firewire, and they all record the exact same DV25 compression as would go to tape. There is no improvement in signal quality by not using tape.
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#4 Andy O'Neil

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Posted 20 July 2004 - 11:15 AM

Thank you, Phil and Mitch,

Forgive me if my questions are repititious, the last thing i want to be is a wet blanket, but here is my question in condensed form:

Is there a way to shoot straight from a camera to a hard-drive (without a computer) and improve signal quality by not using tape?

And if so, what exactly do I need to achieve this? I have a Panasonic DVX100A and i have terabytes of storage. What else do i really need?

thanks,

andy
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#5 David Mullen ASC

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Posted 20 July 2004 - 12:43 PM

The camera only sends out a DV25 4:1:1 signal so you aren't gaining anything by going to tape versus hard drive.
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#6 Andy O'Neil

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Posted 20 July 2004 - 02:20 PM

Thanks, David

I guess Nancy Schreiber ASC had alternative reasons for shooting an "entirely digital desktop movie," http://www.panasonic.../news04_010.asp.

Do you know how I might contact her or find her contact info? Or maybe even the post-production supervisor?

Thanks,

andy
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#7 Andy O'Neil

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Posted 20 July 2004 - 02:32 PM

Just realized I've been posting a faulty web link. Here is a functional one (I hope):

http://www.panasonic.../news04_010.asp

David, to add to what you said...

You said that the color sampling ratio is constant no matter what, however, are there no other image quality factors that could be altered by circumventing tape? i.e. compression?
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#8 Phil Rhodes

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Posted 20 July 2004 - 03:17 PM

Hi,

The compression is done in the camera at a point upstream of both the 1394 output and the tape deck. With the camera in its default state, there is no way to avoid it.

Theoretically you could try and get at the data before it was compressed; this has actually been done to a DVX-100 as a laboratory experiment, and the pictures are fantastically better than those off tape. However, this is a major hardware modification, and you'd need to be a skilled electronics engineer with access to a lot of expensive test equipment to do it.

Phil
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#9 tek

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Posted 17 August 2004 - 09:39 AM

Andy, have you seen this?

http://www.dvxuser.c...eamDV/index.htm
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#10 tek

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Posted 17 August 2004 - 10:12 AM

I am also looking at these:

http://www.focusinfo...store/fs-3.html
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#11 Andy O'Neil

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Posted 17 August 2004 - 12:32 PM

Thanks Tek,

No, I hadn't run across those products yet. It's definitely worth a closer look.
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#12 Carlos M. Icaza

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Posted 17 August 2004 - 01:09 PM

I have been on shoots where the data was recorded to the firestore FS-1. At the same time, it can record to tape as well. I have to say, that it is really a good item to have, only because you don't have to capture the tapes to hd, just keep the tapes as backup. The only problem is that you are going to be tethered to yet another device(or two including the hard drive, at least with the fs-1).


C.-
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#13 tek

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Posted 17 August 2004 - 01:43 PM

I have been on shoots where the data was recorded to the firestore FS-1. At the same time, it can record to tape as well. I have to say, that it is really a good item to have, only because you don't have to capture the tapes to hd, just keep the tapes as backup. The only problem is that you are going to be tethered to yet another device(or two including the hard drive, at least with the fs-1).


C.-

you're welcome andy, who wants to waste an hour or more per tape converting?

hey C, that's why I'm leaning towards the quickstream, it's very compact and has a nice mount...
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#14 Carlos M. Icaza

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Posted 17 August 2004 - 04:00 PM

Tek,

WOW !

That is neat. First time I learn about quikstream. Interesting. Using firewire bus for the power. 90 minutes without charge.

Interesting.... thanks for the tip....

C.-

official link

http://www.mcetech.c...ckstreamdv.html
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