Capture problem using external FW800 drive

I could use some help with video capture on my 1.5 gh, 17" PowerBook ...

Using FC Express or iMovie, I have a problem capturing video from a Canon ZR70M DV camera connected to the FW400 port with an external drive connected via FW800. The external scratch drive is a 300 GB, Maxtor, 7200 RPM 16 MB cache inside of an IOGear enclosure that supports FW800 and USB 2.0. Using either app there are so many dropped frames that it is essentially un-usable. However, if I connect the drive to the PowerBook using USB 2.0, capture works fine. I have seen posts that clearly suggest that the PowerBook firewire ports should be able to negotiate the data traffic with capture coming in on the FW400 and passing the data to the scratch drive using FW800. I have done simple data moves from the PowerBook drive to the external drive using the FW800 connection and it seems to work just fine. I did a simple file movement benchmark compare between the FW800 connection and the USB 2.0 connection and the FW800 is roughly twice as fast (as you would expect).

Suggestions on where to look? The fact that the same behavior occurs in FC Express and iMovie suggests it is not an App setting or disfunction.

Timeing a transfer with a watch isn't directly comparable with video capture. Video doesn't stop. If the drive has to stop for a split second to take a breath, there goes one frame.

For laptop machines, it's recommended to get a FireWire PC Card and put one of the FireWire devices on that and leave the other directly on the machine. Even with FW400 and FW800 on the machine, both are still being managed by the same chipset and it can get overloaded.

Does it start working if you disconnect the FireWire drive and capture a brief segment to an internal drive?

Are any of your drives getting close to filling up? No drive on a video machne should be over 90% full including the System Drive. External FireWire drives get crazy and sloppy when they start filling up.

Koz

Understood and agreed regarding your first comment.

I think your second comment may be valid (I have received this feedback from a co-worker) but I was hoping that Apple would have anticipated this setup (DV camera connect on the FW400 and scratch disc on the FW800) and made sure that the design would allow for it.

To your third point, there is no issue with capturing to the internal drive. Works fine, it's just that the drive is not large enough for big projects (hence the 300 GB scratch drive).

To your final question ... the PowerBook drive is 80GB. There is 26 GB of free space (~ 68% consumed). The scratch drive is brand new and is almost completely available. Fresh format using HFS+ so there should be no issues there.

So I am baffled unless your "FW chipset overload" theory is the source of the problem. Thanks for the reply. If you have any other ideas, please advise.

Joe,

You can kinda get around the limitations Koz describes by capturing to your internal drive in short segments - not to fill up the drive past 90%, then moving those files to your scratch drive, deleting them from the internal, reconnecting them when FCP realizes they're gone from the original location; then capturing some more, etc. Then you're pretty OK to edit the show with everything on the external scratch drive after that. The problem is that capturing is a big load on a busy bus and doing it this way lightens the load. Yes, it's a tedious process but portends greater success.

I do what you're trying to do with a 15" PB 800 MHz 1 GB, with no capture issues, but I knock heavily on wood when I do. Canon cameras are famous for having FW issues, and other drivers are available for them just because of that. Maybe someone can expand on that with more authority than I can.

scott

<<< I was hoping that Apple would have anticipated this setup>>>

Well, they did. Apple had very specific instructions against using two FireWire 400s in the same machine. You would think you could get away with one 400 and one 800, but I guess you're the poster child for no.

I can't prove this on our machines because we don't have configurations like that, but somebody posted that a 800 drive runs at 400 when both connections are used.

I can believe that.

A classic problem is using the front and back connections on a G5 at the same time. Nope. Sorry. You can't do that, either.

Koz

Koz is dead on. However the very newest machines I have heard have separate FW400 and FW800 buses. Don't know if this is true though, just heresay.

So yes, you must get a PCMCIA card with FireWire 800 ports to pull this off without too many problems.

Recall that Apple has never supported the use of FireWire drives of any kind, so as with any unsupported hardware scenario, YMMV.

Kevin Monahan
Author-Motion Graphics and Effects in FCP
Take My Master's Seminar in LA!

I am able to capture using a 1g Alum 15" PB, fw in, USB out to a hard drive.