external hard-drives and dropped frames
 

I have recently read that using external hard-drives for storing video while doing NLE usually has a problem of dropped frames because the external drive is seldom fast enough to keep up with the demands of video. Can anyone say how prevelant this problem really is? Does this mean you need to get the best external drive you can afford? or would that even matter?

I use 4 external USB2 hard drives for editing and have no problems with them. They are simply internal Western Digital 250 GB drives that I have put in enclosures and hook up to a USB hub. I am able to read, write, edit, and burn DVDs from them with no problem at all.

I've used Western Digital 7200 rpm external drives in plumax enclosures with no incident. I've used them daisy chained via firewire as well as in USB 2 on an HP ZD7000 Laptop. Funny thing is, my externals are faster than my 80GB internal (5400 rpm) and I have no dropped frames whatsoever on either.

I purchased my drives from www.pcmicrostore.com. They're great.

I find that the problem with externals is that over time, the controler cards in the boxes tend to go---I can't tell you how many enclosures I have had this problem with.

Thanks guys. I guess the speed of the external drive is what is important here. I'm really looking forward to getting started with NLE and I want to have plenty of hardrive space as to not have anything lacking as far as hardware. I just want to be able to play around and experiment with no snags.

For the fewest problems on PC, you could:

Have firewire devices on their own firewire card/bus. Don't mix FW100 devices (i.e. DV camcorders; they transfer data at 100mbps) and FW400 devices (FW400 hard drives).

For the hard drives, use a reliable chipset. Oxford chipsets are generally considered good and prolific USB2/firewire combo chipsets have problems (may be fixed with firmware flash).

Use decent quality firewire cable. (You shouldn't pay too much for cable though, because there are insane markups on them sometimes.)

With some devices, hotplugging will fry equipment.


I don't think the actual top speed of an external drive is that important as it far exceeds the DV data rate. The main issue is the actual transfer rate in real world conditions, where you may have devices sharing a firewire bus.

Thanks Glenn,
Could you tell me what exactly is a chip set. I was under the impression that the only thing involved with a external harddrive is the drive itself and then plug it in. (I've never used one before)
Is a Chip Set sort of like a driver for the device. Also, what is hot plugging. Thankyou.

In this case, the chipset is the chip which translates the signals from the hard drive interface (typically IDE/PATA, although it could be SATA) to the firewire/IEEE1394 or USB(2) interface and vice versa.

Hot plugging = taking the firewire connector in or out with the drive and computer are powered on.

I do much of my editing on external hard drives now, and although performance is lower than internal drives it's still fine if you buy reliable equipment. Note that a single layer of DV video only requires 3.5 MB/sec of throughput, which is trivial for any external drive provided the interface isn't subject to temporary glitches. Some people have reported problems using USB2 drives and consider firewire drives more reliable, but I've had pretty good luck with the former. So use firewire if you can, but USB2 will probably work most of the time.

If anyone is getting dropped frames on an external drive, they have serious problems. I assume you're talking about DV and that's about 3.5MB/s. A firewire drive (7200 RPM or something) will deliver, depending on chipset and all that guff, 20-30MB/s linear write.

You might have problems compositing multiple DV streams from the same drive, but as you said, you're concerned about capturing not playback

Just don't go rendering to that drive, while capturing, and editing multiple composited video tracks and you'll be OK.

Aaron

Hey Glenn, thanks again for the help. Let me ask you, If you had a choice between a laptop with a pentium 4 processor @ 3.2GHz,
or a pentium(centrino mobile tech.)M processor 740 @ 1.73GHz,
which is the better to have on the laptop for NLE (and lets forget about the battery life). Which is the better processor to have if you are always on A/C power plugged into the wall. Thanks in advance Glenn. Thanks also to Kevin and Aaron.

The 3.2ghz processor should be faster so I would go with that. The Pentium 740 @ 1.73ghz should be roughly equivalent to 2.6ghz (add 50%, which is a guestimate).

1. make sure if the drive is USB that it is USB2 and your computer has USB2 as well

2. if you connect it over firewire, dropped frames (or other problems) can occur if you daisy chain your firewire camera of the harddisk (as most people do with firewire)

Thanks very much. I am learning so much on this site.