problems with dropped frames when shooting to computer in the field

Ike615

Ike615

Well-known member
I was filming a show last night , with my usual setup of having a firewire cord running from my camera to my powerbook G4 and recording in FCP (that has worked flawlessly for everyone of my shoots), and to my horror when I looked down at my computer screen right before the end of the first act it said that it had dropped a frame and as a result had deleted all the previous footage I recorded. So I'm pretty sure it has to do with the firewire connection but I'm also pretty sure it was connected tightly the whole show so I'm wondering if it's just a faulty firewire cord.

I'm filming it again tonight and unless I can be 100% sure it's not going to give me a drop frame again I'll have to shoot in SD, which I'm not too happy about. I'm going to do some tests today with other firewire cords and see if I can get better results.

Does anyone know why FCP completely deletes all the footage you've been capturing when you get a dropped frame? And is there a way around this so that it will keep all the footage up until the dropped frame?

Thanks!

- Isaac
 
How long is your Firewire cable? Longer than spec (4.5 meters) cables may work for DV or HDV, but they are not guarranteed to work with high-bandwidth devices like hard drives or DVCProHD cameras.
 
The PowerBook has one firewire bus.

You shouldn't try to capture to the internal drive in that it probably isn't fast enough. You need at least a 7200 rpm external hard drive connected to the internal FW bus of the cam, and a FW PC card to create a second FW bus and connect that to the cam.

That should clear up the DF issue.
 
Thanks for your replies.

I probably should give more details of my shoot. I was using a 6 foot Firewire cable hooked up to a Powerbook G4. Then I was using a 500GB Lacie external HD. I connected that to my computer using a FW800 cable so the HD shouldn't be the problem.

David, I could get a FW PC card but I don't think the problem is with the FW bus because like I said before I've shot for many hours on end to my Powerbook with both FW cords connected to the same bus without any problems.

I'm just going to shoot in SD tonight and then in the near future go out and purchase another FW cord (preferably a right angle one) and see if it's the cord that's causing the problem.

I'm doing a three cam setup with the other two cameras DVX100s. Now that I'm shooting SD I almost wish I had third DVX100 instead of the HVX for tonight because the HVX needs more light and doesn't look as good in 480i 60i. Oh well. It will still look great.
 
You're not going to get FW800 speeds to the hard drive when the bus is shared with a FW400 device like the camera -- the bus auto-negotiates the speed and will be constrained by the slowest device on the bus.
 
THoff said:
You're not going to get FW800 speeds to the hard drive when the bus is shared with a FW400 device like the camera -- the bus auto-negotiates the speed and will be constrained by the slowest device on the bus.
Click to expand...

Ditto.

And that's essentially what Adam Wilt indicates.

Spring for a $50.00 PC Cardbus FW card, and it will spare you some headaches.

Again, your set up works until it doesn't, and it is not the optimal or foolproof way to capture directly into FCP with a one FW bus Mac.
 
You're probably both right. And $50 isn't very much so I'll definitely invest in a PC Cardbus FW card before my next shoot. Thanks for the help.

I shot the show tonight in SD and it went very well. So even though I wasn't able to shoot in HD I was very happy with how it turned out.
 
For what it's worth, I've shot tons of HD with both devices on the Powerbook's firewire bus without as problem... with the caveat that I use Glyph drives for capture, and they seem to avoid problems other FW drives cause.

Once, when using a cheapo USB (!) drive to capture to, I had some problems with drop frames and timecode breaks... but a restart solved them. Not what you want to deal with during a shoot - get a Glyph!

As for FCP settings, yes, in the preferences, uncheck all the "abort capture on..." settings. Also, if you're paranoid, limit the maximum capture file size to some small number (2 GB?) so that FCP writes a bunch of small files rather than one big one - which also limits the amount of material you'll lose if there's a problem.
 
ullanta said:
I use Glyph drives for capture, and they seem to avoid problems other FW drives cause..
Click to expand...

Ullanta,

What Glyph drive are you using, the PortaGig or one of the desktop models? I have been looking into the 7200rpm PortaGig bus-powered drive for DDR in the field, and wonder whether they are adequate for that purpose.

Thanks,
Kevin
 
I've been using GT-050 FW400 drives... but I'd trust the PortaGig. I've had luck with the OWC Mercury On-The-Go 7200 RPM firewire bus-powered drives as well - no major problems, but not as solid as a Glyph. That is, the OWCs have never hiccupped during recording, but, e.g., they won't mount on when connected to one of the ports on my G5, yet work fine on the others and on my powerbooks. I've had the same problem with G-Drives. Not a terrible problem, but definitely the kind of things that doesn't seem to ever come up with Glyphs...
 
Michael_Richard said:
what about unchecking abort capture on dropped frames in preferences
Click to expand...
I was about to say that. But also the problem could be that your harddrive is too fragmented. I had the same problem recently capturing some SD footage (on a diff camera) and did some research. I found out that a fragmented harddrive will drop frames. The harddrive I capture to, I know is framented, i'm constantly putting big files, and then deleting and trashing them. I plan on getting an external 500gb MYbook to back up and so I can wipe the capture drive clean. Try that.
 
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